Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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U.S. Environmental Protection Agency

Cement Sector 

Trends in Beneficial Use of Alternative 

Fuels and Raw Materials

Revised 

Draft

October

2008

Prepared for:

U.S. Environmental Protection Agency

Office of Policy, Economics, and Innovation

Sector Strategies Division

Prepared by:

ICF International

1725 I Street, Suite 1000

Washington, DC 20006

(202) 862-1100
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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Contents

Executive Summary .......................................................................................................... 6

Objective ......................................................................................................................... 6

Approach......................................................................................................................... 6

On the usage of the Term “Waste” ................................................................................. 7

AFR Utilization in Cement Production........................................................................... 9

Conventional and Alternative Fuel Characteristics ...................................................... 10

Pros and Cons of Alternative Fuel and Raw Material Use in Cement Kilns................ 11

Key Findings................................................................................................................. 17

Key Opportunities and Options .................................................................................... 17

1. Introduction ............................................................................................................ 19

2. Background.............................................................................................................. 21

2.1 Study Overview............................................................................................... 21

2.2 Cement Kiln Technology ............................................................................... 22

2.2.1 Cement Production .................................................................................... 24

2.3 Alternative Fuels and Raw Materials (AFR)................................................. 24

2.4 On the usage of the Term “Waste”..................................................................... 26

3. Beneficial Use Materials Prioritization................................................................. 28

3.1 Development of Materials Prioritization List and Criteria ........................ 28

3.1.2 Study Methodology .................................................................................... 29

3.1.3 Alternative Fuels Methodology ................................................................. 31

3.1.4 Alternative Raw Materials Methodology.................................................. 31

3.2 Criteria Application and Prioritization Results........................................... 31

3.2.1 Spent Foundry Sand ................................................................................... 32

3.2.2 Steel Slag...................................................................................................... 32

3.2.3 Scrap paper/wood and C&D debris .......................................................... 33

3.2.4 Refinery spent catalyst and clarified slurry oil sediments...................... 34

3.2.5 Other Prioritization List Materials ........................................................... 35

3.3 Emerging Materials......................................................................................... 39

3.3.1 Wastewater treatment sludge (biosolids)................................................ 39

3.3.2 Plastics.......................................................................................................... 40

3.3.3 Automobile shredder residue (ASR)......................................................... 40

3.3.4 Carpet Scrap ................................................................................................ 41

3.3.5 Other Materials........................................................................................... 42

4. Case Study Summations......................................................................................... 42

4.1 Alternative Fuels ............................................................................................ 42

4.1.1 Cost Issues ................................................................................................... 42

4.1.2 Technical Issues .......................................................................................... 45

4.1.3 Regulatory Issues ........................................................................................ 47

4.1.4 Supply/Logistics Issues .............................................................................. 51

4.1.5 Trends Analysis ........................................................................................... 52

4.1.6 Emerging Materials..................................................................................... 54
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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4.2 Summary – Alternative Fuels ........................................................................ 54

4.2.1 Scrap Paper/Wood and C&D Debris ........................................................ 54

4.2.2 Refinery Spent Catalyst and Clarified Slurry Oil Sediments.............. 55

4.2.3 Scrap Tires ................................................................................................... 57

4.2.4 Wastewater Treatment Sludge (Biosolids) .......................................... 58

4.2.5 Plastics...................................................................................................... 59

4.2.6 Automobile Shredder Residue .............................................................. 60

4.2.7 Emerging Materials................................................................................. 60

4.3 Alternative Raw Materials............................................................................. 62

4.3.1 Cost Issues ................................................................................................... 62

4.3.2 Technical Issues .......................................................................................... 62

4.3.3 Regulatory Issues ........................................................................................ 63

4.3.4 Supply/Logistics Issues .......................................................................... 64

4.3.5 Trends Analysis ........................................................................................... 65

4.3.6 Other Emerging Materials ..................................................................... 65

5. Conclusions ............................................................................................................. 65

5.1 General Observations ..................................................................................... 66

6. Recommendations/Further Actions ..................................................................... 71

7. Appendix A: Case Studies ...................................................................................... 73

7.1 Beneficial Use Case Studies ........................................................................... 73

7.1.1 Spent Foundry Sand ................................................................................... 73

7.1.2 Steel Slag...................................................................................................... 76

7.1.3 Scrap Paper/Wood...................................................................................... 77

7.1.4 Refinery Spent Catalyst and CSOS............................................................ 80

7.1.5 Wastewater Treatment Sludge (biosolids) .............................................. 86

7.1.6 Plastics.......................................................................................................... 87

7.1.7 Scrap Tires ................................................................................................... 89

7.1.8 Automobile Shredder Residue .................................................................. 95

7.1.9 Miscellaneous Materials............................................................................. 96

8. Appendix B: Study Contacts ................................................................................ 104

9. Appendix C: Kiln Types........................................................................................ 106

9.1 Wet Process ............................................................................................... 106

9.2 Long Dry Process ...................................................................................... 106

9.3 Variations of the Dry Process .................................................................. 106

9.4 Dry Process with Gas-Suspension Preheaters: ...................................... 107

9.5 Precalciner Kilns ....................................................................................... 107
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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List of Tables

Table 1: Share of AFR in Total Fuel Demand in the Cement Industry of Selected Countries

Table 2: Wet and Dry Kilns in the U.S.

Table 3: U.S. Cement Clinker Production

Table 4: Energy Derived from Fuels Used in Cement Production

Table 5: Heat Value of Conventional and Alternative Fuels

Table 6: Beneficial Reuses of Foundry Sands According to American Foundry Society 

Survey 

Table 7: Annual Generation and Management Methods of K170 Hazardous Waste 

(Clarified Slurry Oil Sediments) 

Table 8: Annual Disposition of K170 Hazardous Waste (CSOS) Managed through Energy 

Recovery

Table 9: NAICS 32411 GM Forms, Management Code H050 and H061, Outlier and Mixed 

Waste Excluded 

Table 10: Scrap Tires Used as Alternative Fuels in Cement Production

Table 11: Cost of Coal in Selected States

Table 12: Landfill Tipping Fees, 2004
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

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Executive Summary 

Objective 

This report analyzes recent trends in 

beneficial use of alternative fuels and raw 

materials (AFR) in cement production. The 

overall objective of the study is to promote 

increased utilization of beneficial use 

materials in cement kilns by identifying 

trends and cost, technical, supply/logistics, 

and regulatory barriers to increased 

utilization of these materials. Alternative 

fuels considered in this study include 

petroleum refinery spent catalyst and clarified 

slurry oil sediments (CSOS), scrap 

paper/wood, construction and demolition 

(C&D) debris, scrap tires, wastewater 

treatment sludge (biosolids), plastics, and 

emerging materials including scrap carpet and automobile shredder residue (ASR). 

Alternative raw materials considered in this study include spent foundry sand and steel 

slag used as a cement kiln raw material. Slag used as a clinker additive is outside the 

scope of this report. 

Approach 

To analyze trends in beneficial use of alternative fuels and raw materials, EPA Sector 

Strategies Program (SSP) interviewed cement plant contacts, regulatory agency contacts, 

and AFR suppliers concerning use of AFR in cement kilns. Initial contacts were identified 

through discussions with the Portland Cement Association (PCA). PCA and EPA also 

coordinated a meeting with API representatives to discuss technical and regulatory issues 

related to clarified slurry oil sediments issues. State and local regulatory agency contacts 

were identified through the telephone interviews with cement plant contacts and 

petroleum refinery contacts. Cement plant contacts and regulatory agency contacts 

identified suppliers of AFR, including contacts at the cement companies’ wholly-owned 

subsidiaries and independent alternative fuel suppliers. 

SSP developed topics of discussion to address the initially prioritized beneficial use 

materials of spent foundry sand, steel slag, scrap paper/wood, C&D debris, and refinery 

spent catalyst and clarified slurry oil sediment. The interview guides aided in telephone 

interviews with cement plant, regulatory agency, and AFR supplier contacts. Specific 

areas of discussion included the types of beneficial use materials utilized by the plant, the 

sources of those materials, past and anticipated trends in the supply of materials and the 

plant’s utilization of materials, and the technical and regulatory issues associated with the 

utilization of materials. Agency contacts discussed state and local regulatory issues, 

permitting and performance testing issues, public perception issues, economic programs 

in the states, and other issues that arose during discussions. 

Alternative Fuels and Raw Materials 

Included in this Report

 Automobile shredder residue

 Plastics 

 Refinery waste/clarified slurry 

oil sediment/refinery spent 

catalyst

 Scrap carpet

 Scrap paper / wood 

 Construction/demolition debris

 Scrap tires

 Spent foundry sand

 Steel slag

 Wastewater treatment sludge
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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The topics of discussion expanded as the telephone interviews progressed. In some cases 

follow-up calls were made to specific cement plant contacts to obtain additional 

information concerning issues that arose in other interviews or to obtain additional

cement plant contacts, regulatory agency contacts, or AFR supplier contacts. These 

discussions led to the identification of “emerging issues,” concerning alternative fuels that 

are either in use or being investigated by the cement plants. For these additional 

alternative fuel materials, SSP developed material-specific analysis and “emerging issue” 

case studies based on interviews with cement plant contacts and state and local regulatory 

agency contacts. These “emerging” materials include:

• Wastewater Treatment Sludge (biosolids)

• Plastics 

• Automobile Shredder Residue (ASR)

Emerging issues concerning utilization of scrap tires in cement kilns were also identified 

by cement plant and regulatory agency contacts. Therefore, additional analysis of scrap 

tires was conducted for this report, and case studies were developed for utilization of 

scrap tires. 

SSP also conducted research into specific regulatory issues concerning alternative fuels

and conducted meetings with SSP counterparts for other Industry Sectors to obtain 

additional perspective on sector-specific issues. 

On the usage of the Term “Waste”

Beneficial use of industrial materials (referred to in the cement sector as coprocessing) 

involves transferring industrial byproducts from one industrial sector to another. Such 

transfers can reveal differences in perspectives between industry sectors concerning the 

definition of the industrial byproducts involved. Industrial byproducts have historically 

been referred to as “wastes,” even in cases where such products are recovered, rather than 

disposed of, and used as alternative fuels or alternative raw materials. “Waste oil,” which 

may be burned for energy recovery, is one example of such terminology. Both the cement 

industry and other industry sectors have adopted the terminology “alternative fuels and 

raw materials” (AFRs) to refer to industrial byproducts used as alternative fuels and as 

alternative raw materials, however these materials are still referred to as “wastes” in 

cement sector and other industry sector documents. For example, the Portland Cement 

Association (PCA) Annual Labor and Energy Report 1refers to “waste, oil,” “waste,

solvents,” and “waste, other solids” as fuel type categories, and the U.S. Geological Survey 

Minerals Yearbook for Cement refers to “liquid waste” as a fuel type category. 2 Other key 

documents that use the term “waste” in this context include EU Directive 94/67/EC, and 

the World Business Council for Sustainable Development (WBCSD) Cement Sustainability 

Initiative (CSI) “Guidelines for the Selection and Use of Fuels and Raw Materials in the 

Cement Manufacturing Process Cement Sustainability Initiative” (December 2005).3

The generators of industrial byproducts (e.g., petroleum refineries) may be more inclined 

to refer to these industrial byproducts as “raw materials,” “feedstocks,” or “products” than 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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are the users of the industrial byproducts (e.g., cement kilns). This is in part because the 

cement sector and other industry sectors have historically been paid fees to accept such 

“wastes” from generators, while the petroleum refineries and other industrial byproduct 

generators have been paid to deliver their facilities “products” to customers. More 

recently, suppliers of alternative fuel to cement kilns, including cement company whollyowned subsidiaries and private companies, have adopted terms such as “engineered fuel” 

when referring to fuels derived from many different industrial byproduct streams. The 

preparation process used to produce this fuel adjusts for the technical and administrative 

specifications of cement, and guarantees that environmental standards are met

independent of the specific industrial byproduct streams used in its production.

4

Also note that the terminology of “waste” and specific regulatory definitions of “waste” 

(e.g., “hazardous waste;” “solid waste;” “municipal solid waste”) date back several decades. 

The term “waste” has therefore come into general usage as applied to industrial 

byproducts even in cases where the material is not defined by regulation as a waste. 

EPA generally has regulated units that process materials (waste or otherwise) for energy 

recovery under the Clean Air Act (CAA) Section 112, Maximum Achievable Control 

Technology (MACT) standards, such as the Portland Cement Kiln MACT, Industrial Boiler 

MACT, and the Pulp and Paper MACT. However, the DC Circuit recently vacated and 

remanded two EPA rules promulgated under the CAA – the Commercial and Industrial 

Solid Waste Incineration (CISWI) definitions rule, issued under section 129 of the Act, and 

the Boiler MACT, issued under section 112 of the Act. The court concluded that EPA erred 

by excluding units that combust solid waste for purposes of energy recovery from the 

CISWI rule and including such units in the Boiler rule. 

In response to the court’s decision, EPA is currently examining the use of various materials 

by industries, including the cement industry, and is in the process of conducting a 

rulemaking to determine which materials are solid wastes under RCRA, subtitle D. EPA 

also is establishing new standards under both 112 and 129 for the various units subject to 

each section, as the community of units regulated under each section will change as a 

result of the ruling. A separate MACT Standard for hazardous waste combustors (HWCs) 

applies to cement kilns that burn hazardous waste. In general, cement kilns operate 

under Title V Operating Permits issued by state regulatory agencies implementing Clean 

Air Act programs.

Specific types of “waste” are defined in the Resource Conservation and Recovery Act 

(RCRA) and other statues and regulations. For example, RCRA Hazardous Waste Code 

K170 waste is defined as: Clarified Slurry Oil (CSO) storage tank sediment and/or in-line 

filter/separation solids from petroleum refining operations. 5 This material is referred to 

in this document as Clarified Slurry Oil Sediments (CSOS). This material is categorized as 

a “RCRA hazardous waste.” 

Lastly, EPA’s Office of Solid Waste and Emergency Response (OSWER) is currently 

considering organizational changes that, among other things, reflect the growing trend to 

view waste management as resource recovery and reuse opportunities, as appropriate. The

cement and other industries are finding new ways to use materials that have historically 

been discarded or treated as wastes. Industrial facilities are reusing byproducts or waste 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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materials in their own operations or sending them elsewhere for reuse as a substitute fuel 

or raw material. EPA values such beneficial reuse, and recognizes the many opportunities 

associated with converting waste products into valuable commodities.

The term “waste” in this document is not intended to connote any regulatory classification 

except when the term “waste” is used in phrases such as “RCRA hazardous waste;” “solid 

waste;” and “municipal solid waste,” which are terms defined in EPA regulations. Other 

uses of the term “waste” (e.g., “waste oil”) in this document are derived directly from the 

terminology used in the source documents (e.g., the PCA Labor and Energy Report; the 

USGS Cement Minerals Yearbook) and do not and are not intended to connote any 

regulatory classification of the material. 

AFR Utilization in Cement Production

Table ES-1 provides a summary of utilization of conventional and alternative fuels in 

cement production in the U.S. in 2006. Data are provided in mass units and energy 

(BTU) units for conventional fuels and in energy units for alternative fuels. Note that 

available data for utilization of alternative fuels in cement production do not identify the 

specific type of alternative material (e.g., biosolids, wood) but rather identifies “Waste

Oil;” Waste Solvents;” “Waste Other Solids;” and “Waste Miscellaneous” as separate 

general categories of alternative fuel materials. In general, utilization of alternative fuels 

other than solvents (including hazardous waste solvents) and scrap tires in cement kilns is 

relatively low. Alternative fuels other than scrap tires and solvents collectively 

represented approximately 2.5 percent of the total energy (BTU) input to cement kilns in 

2006; scrap tires represented approximately 3.6 percent of the total energy input to 

cement kilns in 2006. According to USGS data, approximately 400,000 metric tons of 

scrap tires were used as alternative fuel in cement production in 2005. Tire derived fuel

represents 52 percent of scrap tires generated.1 The cement sector represents 38 percent of 

the market for tire-derived fuel, according to the Rubber Manufacturers Association 

(RMA).

Table ES-1 Energy Derived from Fuels Used in Cement Production

Fuel Type Quantity Used in 

Cement Production

Btus (billions) Used in 

Cement Production

Coal 9,997,231 tons 226,539.64 64.05%

Petroleum Coke 2,560,737 tons 74,900.71 21.18%

Natural Gas 12,723 million cu. ft. 12,939.29 3.66%

Middle Distillates 20,766,405 gallons 2,875.66 0.81%

Residual Oil 3,534,995 gallons 523.99 0.15%

Gasoline 1,485,385 gallons 185.61 0.05%

LPG 950,379 gallons 81.81 0.02%

Waste Oil -- 1,008.72 0.29%

Waste Solvents -- 14,026.48 3.97%

Tire Derived Fuel -- 12,622.12 3.57%

Other Solids -- 2,686.92 0.76%

Waste - Miscellaneous 5,311.63 1.50%

 

1

For 2005, the Rubber Manufacturers Association reports that 728,000 metric tons of scrap tires were used 

as alternative fuel in cement production in 2005, representing 18% of total quantity generation, and 37% of 

total quantity used for fuel.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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Total 353,702.58 100.00%

Source: PCA, U.S. and Canadian Labor-Energy Input Survey 2006

Table ES-2 summarizes generation, and onsite and offsite management of CSOS. In 2005,

only 24 short tons of CSOS were reported to be sent to cement kilns for energy recovery, 

representing only 0.15 percent of the approximately 16,000 short tons of CSOS generated 

by petroleum refineries managed offsite. This is as compared to approximately 5,000 

short tons of CSOS sent to cement kilns for energy recovery in 2001 (16 percent of total) 

and 700 short tons (2 percent of total) in 2003. 

Table ES-2 Beneficial Use of CSOS in Cement Production

Year

CSOS sent to 

cement kilns

(Short Tons) 

Total CSOS 

Managed Offsite

(Short Tons)

Percent of 

Total

2001 4,949.60 30,909 16.01%

2003 698.10 32,408 2.15%

2005 24.31 16,376 0.15%

Source: EPA Hazardous Waste Reporting System (2006)

Utilization of alternative raw materials (i.e., spent foundry sand, steel slag) in cement 

production is also relatively low. As shown in Table ES-3, utilization of spent foundry 

sand in “other” beneficial use applications, which includes use as a raw material in cement 

production, represented only approximately 11 percent of beneficial use. Utilization of 

steel slag and other slag as raw material in cement production represented approximately

5 percent of overall sales of slag for beneficial use. 

Table ES-3 Beneficial Use of Raw Materials in Cement Production

Material Type Beneficial Use 

Metric tons (2005)

Percent of Total 

Beneficial Use

Spent Foundry Sand

Not specified/Other (including use as 

a raw material in cement production) 292,928 11.07%

Total Beneficial Use 2,645,427 100%

Steel Slag and Other Slag

Steel Slag 500,000 2.5%

Other Types of Slag 500,000 2.5%

Total Slag used as raw material in 

cement production 1,000,000 5.0%

Total Beneficial Use 20,300,000 100%

Source: American Foundry Society Bench Marking Survey (2007)

Conventional and Alternative Fuel Characteristics

Table ES-4 summarizes the energy content of conventional and alternative fuels used in 

cement production. Many alternative fuels used in cement production have lower energy 

content than coal, the primary conventional fuel used in cement production, or require 

further processing to increase the energy content to the approximate energy content of 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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coal. This means that for some types of alternative fuels, e.g., biosolids, 1.5 tons or 2 tons 

of the alternative fuel may be needed to replace one ton of coal. This is a factor in both 

the operation of the cement kiln and in the transportation cost of the alternative fuel.

Also, use of alternative fuels for energy recovery, replacing conventional fuels, reduces 

emissions of greenhouse gases (specifically carbon dioxide) from cement production, 

particularly where the alternative fuel is a “carbon neutral” material such as biosolids or 

scrap paper/wood. 

Table ES-4: Lower Heating Value (LHV) of Conventional/Alternative 

Fuels

Fuel Type Btu/Pound Notes

Coal 11,300

Petroleum Coke 14,600

Paint Residues 7,000

Plastics 18,700 Polyethylene

12,000 Mixed non-chlorinated

Refuse-derived Fuel 6,500-7,000 Post-processing

Scrap Carpet 7,300 – 12,000 Nylon; Polypropylene

12,000 – 15,000 Post-processing

Scrap Tires 14,000 Tire-derived fuel

Automobile Shredder Residue 7,000 Pre-processing

10,000 Post-processing

Clarified Slurry Oil Sediments 8,000 - 9,000 Centrifuged

Biosolids 7,000-8,000 Class A Dry

Paper/Cardboard 8,500 Dry

Sawdust 7,000 Dry

Wood 6,500 – 7,500 Dry

Engineered Fuel 10,000 [processed Wet Kiln Fuel]

6,500-8,000 [processed Dry Kiln Fuel]

Sources: Cement Industry Contacts; Murray, A.E., and Price, L., 2008.

Pros and Cons of Alternative Fuel and Raw Material Use in Cement 

Kilns

Table ES-5 summarizes the benefits, barriers, technical drawbacks, and other issues 

related to AFRs included in this report.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

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Table ES-5. Summary of Alternative Fuel and Raw Material Benefits, Barriers, Technical Drawbacks, and Other Issues

AFR Benefits Barriers Technical Drawbacks Other Issues

Automobile 

shredder residue 

(ASR)

High calorific value; after 

processing, energy content 

similar to coal.

ASR has raw material value; 

silicates, calcium, aluminum, 

and iron content would 

replace the need for mined 

material

High availability because 

almost all ASR is landfilled.

Lowers landfill demand.

TSCA regulations categorize ASR as 

a “PCB Waste.” This represents a 

regulatory barrier to use of ASR for 

energy recovery, therefore most 

ASR is landfilled.

ASR can contain mercury (within 

mercury switches), lead, and copper 

from content of scrap automobiles; 

these elements can affect cement 

kiln air emissions.

Technologies to upgrade the 

quality of ASR for suitable use 

within a cement kiln may not be 

cost effective.

Treatment technologies that 

separate ASR into higher value 

high-purity plastics may compete 

with ASR use as alternative fuel, 

depending upon waste 

management hierarchy

Modification of regulatory TSCA

waste classification applicable to 

ASR may facilitate the use of ASR as 

an alternative fuel in cement kilns. 

According to cement sector 

contacts, EPA Region VI is 

interpreting EPA regulation 

“Disposal of PCB bulk product 

waste” in a way that automobile 

shredders that generate ASR cannot 

certify compliance. 

Performance testing and air permit 

modifications generally required; 

continuous emissions monitoring 

system (CEMS) installation may 

also be required prior to initiating 

AFR use; these represent added cost

Plastics High calorific value; energy 

content similar to coal.

Recycling reduces landfill 

gas emissions.

Represents new use for 

unrecyclable plastics 

categories (b and c) that 

would otherwise go to 

landfill.

Difficult to generate consistent 

quantities of material; plastics 

waste from multiple generators may 

need to be consolidated.

Recyclable plastics are often sent to 

post-consumer plastic recyclers; 

cement plants do not want to 

compete with recyclers or conflict 

with waste management hierarchy. 

Use of chlorinated plastics can 

Difficult to manage the quality of 

the material if commingled with 

general MSW stream, other nonplastic materials, and chlorinated 

plastics. Segregation of materials 

requires additional capital and 

labor costs.

Generators (local governments) 

may need to install equipment 

and establish procedures to 

adequately segregate plastics in 

Performance testing and air permit 

modifications are generally required 

for plants to initiate AFR use; CEMS 

installation may also be required 

prior to initiating AFR use. These 

represent additional cost.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

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Table ES-5. Summary of Alternative Fuel and Raw Material Benefits, Barriers, Technical Drawbacks, and Other Issues

AFR Benefits Barriers Technical Drawbacks Other Issues

Lowers landfill demand. increase emissions of PCDD/PCDFs 

and also affect clinker quality.

the MSW and supply the plastic 

for use in cement kilns.

Refinery spent 

catalyst / clarified 

slurry oil 

sediments (CSOS)

Calorific value of CSOS; after 

processing, somewhat lower 

than coal 

CSOS has raw material value; 

CSOS alumina and silica

content would replace the 

need for mined material

Most CSOS is treated onsite 

by refineries or treated 

offsite for disposal; beneficial 

use would recover energy 

and raw material value.

Refinery spent catalyst has 

raw material value, replacing 

the need for mined material.

CSOS can only be managed by 

offsite facilities with hazardous 

waste facility permits; utilization is 

constrained by the logistics and 

geographic relationship of CSOS 

generators and RCRA permitted 

cement kilns and other facilities.

CSOS is not generated on a 

continuous basis; one refinery 

would not generate sufficient 

material to continuously supply a 

cement kiln; material from several 

refineries may need consolidation.

Refineries pursing reclassification of 

CSOS so the material would be 

regulated as a refinery product 

rather than a hazardous waste. 

The number of cement kilns 

permitted to combust hazardous 

waste has decreased nationwide 

because of public perception issues, 

EPA enforcement and regulatory 

requirements, and related costs. 

Onsite management/reuse of CSOS 

by refineries avoids regulatory 

classification as hazardous waste or 

TRI reporting as an offsite transfer, 

but use as AFR material at cement 

kilns would be a more optimal 

disposition.

Scrap carpet Calorific value; after 

processing, scrap carpet 

energy content is similar to 

that of coal.

Scrap carpet has raw 

material value; calcium 

carbonate would reduce 

demand for mined material.

High potential availability 

Difficult to generate consistent 

quantities of material; scrap carpet 

from multiple generators may need 

to be consolidated.

Centralized collection of material is 

difficult, as there are large numbers 

of small generators of scrap carpet.

Using scrap carpet as an AFR has 

the potential to affect cement kiln 

Preprocessing is needed to make 

alternative fuel from scrap 

carpet. Carpet is made to be 

highly durable, making scrap 

carpet difficult to shred.

Separating scrap carpet from 

other debris at point of 

generation involves labor costs; 

small scale carpet installers 

require training in preventing 

Permit modifications and 

performance testing are generally 

required prior to initiating AFR use; 

CEMS installation may also be 

required prior to initiating AFR use. 

These represent additional cost.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

14

Table ES-5. Summary of Alternative Fuel and Raw Material Benefits, Barriers, Technical Drawbacks, and Other Issues

AFR Benefits Barriers Technical Drawbacks Other Issues

because almost all scrap 

carpet is landfilled.

Lowers landfill demand.

NOx emissions because of nitrogen 

content of the scrap carpet.

contamination with materials 

such as scrap wood, nails.

Scrap paper / wood Calorific value, but relatively 

low as compared to coal.

Quantities are available 

because some material is 

currently landfilled.

Lowers landfill demand.

Use of “CO2 neutral” 

alternative fuels lowers 

greenhouse gas emissions 

from cement production.

Difficult to generate consistent 

quantities of materials; wood and 

scrap paper from multiple 

generators may need to be 

consolidated.

Recyclable scrap paper is often sent 

to post-consumer paper recyclers; 

cement plants do not want to 

compete with recyclers, and plants 

do not want to conflict with waste 

management hierarchy for paper.

Feasibility of processing material 

into consistent physical 

condition for conveyance into 

kiln.

Capital cost for equipment to 

prevent sawdust from becoming 

wet and prevent fugitive dust 

emissions.

Permit modifications and 

performance testing generally 

required prior to initiating AFR use; 

CEMS installation may also be 

required prior to initiating AFR use. 

These represent additional cost.

Construction and Calorific value, but relatively C&D debris is not generated on a Variable quality of the C&D Several states (including MA, NY) 

demolition debris low as compared to coal.

Lowers landfill demand 

continuous basis; difficult to ensure 

a consistent supply of C&D debris 

for use in making alternative fuel.

Logistics and transportation of C&D 

debris use are more difficult than 

relatively homogenous wood waste 

material generated by a lumber mill 

or a landscape services provider.

debris as generated requires 

segregation of material to 

produce C&D debris of 

consistent quality to make 

alternative fuel. Onsite 

segregation of C&D debris 

involves capital and labor costs. 

Feasibility of processing C&D 

debris into consistent physical 

condition for conveyance into 

kiln depends on quality of the 

material as generated.

have recently banned disposal of 

C&D debris in landfills, increasing 

the potential supply of C&D debris 

for use in making alternative fuel.

Scrap tires Calorific value of scrap tires Increasing competition for scrap Some cement kiln designs are Performance testing and air permit 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

15

Table ES-5. Summary of Alternative Fuel and Raw Material Benefits, Barriers, Technical Drawbacks, and Other Issues

AFR Benefits Barriers Technical Drawbacks Other Issues

similar to coal; scrap tires 

also have raw material (iron) 

value

Use of scrap tires can reduce 

cement kiln NOx emissions.

Iron recovered from tires 

reduces the quantity of iron 

needed from mined sources.

Use of scrap tires reduces 

landfilling, and reduces 

health and environmental 

concerns from piled scrap 

tires; this can be integral part 

of state government scrap 

tire programs. 

tires from other beneficial users.

Waste management hierarchy 

interpretation may affect the 

perception of use of scrap tires for 

energy recovery as opposed to 

recycling scrap tires into other uses.

Some state and local regulations 

allow scrap tires to be disposed in 

non-hazardous solid waste landfills; 

this affects the available supply of 

scrap tires.

Potential public perception and 

communications issues associated 

with scrap tire use in cement kilns.

not able to use whole scrap tires

and would need to use chipped 

tires; chipping tires is costly and 

is not always cost effective.

modifications are generally required 

for plants to initiate AFR use; CEMS 

installation may also be required 

prior to initiating AFR use. These 

represent additional cost.

Spent foundry sand Spent foundry sand has raw 

material value; specifically 

silica.

Silica content of spent 

foundry sand substitutes for 

mined raw material.

Lowers landfill demand

In some states this material is being 

stockpiled or landfilled; this affects 

the available supply of the material.

Cost and technical issues related to 

quality of the material as generated. 

Cement plants (or generators) must 

screen lower quality spent foundry 

sand to remove metal and other 

extraneous materials, making lower 

quality spent foundry sand not as 

desirable as mined raw material.

Spent foundry sand can be used as a 

Phenolic resin binder content of 

the spent foundry sand may not

be compatible with 

preheater/precalciner kiln design

and can affect carbon monoxide 

emissions from cement kilns.

Spent foundry sand can be more 

difficult to grind that mined 

sand; extraneous material can 

damage grinding equipment.

Some cement plants have an 

inexpensive supply of mined raw 

Some states do not have active 

regulatory management programs 

for spent foundry sand, permitting 

the material to be landfilled.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

16

Table ES-5. Summary of Alternative Fuel and Raw Material Benefits, Barriers, Technical Drawbacks, and Other Issues

AFR Benefits Barriers Technical Drawbacks Other Issues

construction material; competing 

uses for spent foundry sand, 

including construction fill, are less 

sensitive to the material’s quality.

material containing silica and 

therefore would not need to use 

spent foundry sand, even if the 

material was readily available. 

Steel slag Steel slag has raw material 

value; specifically silicates. 

Silicate content of steel slag 

would substitute for mined

material; reducing demand 

for mined material.

Competition from concrete batch 

plants using steel slag as an additive 

in cement production may affect 

the market for steel slag use as a 

cement kiln raw material.

Requires particular quality of 

slag for use in kiln.

Some cement plants have an 

inexpensive supply of mined raw 

material containing silica and 

therefore would not need to use 

steel slag, even if the material 

was readily available.

Wastewater 

treatment sludge

Calorific value, but relatively 

low as compared to coal even 

after drying the material.

Lowers landfill demand.

Material is potentially widely 

available in metropolitan 

areas; large supply and 

continuously available.

Potential public perception and 

communications issues associated 

with biosolids use in cement kilns.

Existing infrastructure for biosolids 

management is largely based on 

land application of the biosolids.

Requires drying the biosolids 

material before use in kiln.

Biosolids as generated contain 

pathogens. Classification of 

biosolids is based on pathogenic 

organisms content of material; 

some jurisdictions limit cement 

plants’ use of the material to 

Class A material that has been 

heat processed to remove 

pathogens; this can effectively 

reduce the net amount of energy 

recovered from the material.

Performance testing and air permit 

modifications are generally required 

for plants to initiate AFR use; CEMS 

installation may also be required 

prior to initiating AFR use. These 

represent additional cost.

Use of “CO2 neutral” 

alternative fuels lowers 

greenhouse gas emissions 

from cement production.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

17

Key Findings

This analysis produced the following key findings:

 Primarily driven by cost considerations, the principal focus of cement plants’

beneficial use of alternative fuels rather than on the beneficial use of alternative 

raw materials. 

 Most cement plants noted that use of alternative fuels is important to the 

continued competitiveness of their plants.

 Technical considerations regarding materials handling arose frequently during 

interviews, and affected key decisions on plants’ uses of materials. Often, for 

instance, a decision to use one alternative fuel or raw material precludes the use of 

another material because of materials handling system limitations.

 State agency contacts generally indicated that agencies are promoting beneficial 

use at a relatively low level; cement plant and state agency contacts indicated that 

the market has been more efficient than state agencies at matching alternative fuel

and raw material suppliers and users.

 There is a growing commercial market for brokers that may consolidate quantities 

of materials into larger shipments to cement plants and may process the material 

prior to shipment.

 Significant differences exist in the corporate management of beneficial use of 

materials. Some corporations set benchmarks for their cement plants and the 

plants may work on pilot projects, while other companies contain plants acting 

more autonomously. 

Key Opportunities and Options

Much of AFR being used in cement kilns provide natural synergies between the cement 

sector and other SSP sectors, including:

 Automobile Manufacturing: Automobile Shredder Residue

 Automobile Parts Manufacturing: Plastics 

 Oil and Gas: CSOS, Refinery Spent Catalyst

 Metal Casting: Spent Foundry Sand

Partnerships between the cement sector and other SSP sectors could leverage the strong 

interest expressed in interviews in collaboratively examining the issues associated with 

distribution and use of alternative fuels and raw materials. Also, partnerships between 

sectors and state agencies with active beneficial use promotion programs could promote 

establishment and expansion of such programs. Note that regional differences, as well as 

state and local regulatory frameworks, play a key role in the factors of cost, quantity, and 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

18

quality of AFR. Approaches to further actions would be most efficient when informed by 

such differences.

Recommendations for further actions are based on conclusions (observations) concerning 

beneficial use materials supply and demand and cost, technical, and regulatory issues; 

potential health effects of beneficial use of materials is outside of the scope of this report; 

however, the use of AFR at cement kilns would be subject to the full suite of safety, health, 

environmental, and transportation regulations applicable to any commercial fuels and raw 

materials used at those locations. Potential public perception and associated public 

communications issues related to beneficial use of materials are also outside of the scope 

of this report. The potential for health effects and public perception/communications will 

need to be considered in evaluating and implementing recommendations for further 

actions. 

 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

19

1. Introduction 

The overall objective of the study is to promote increased utilization of beneficial use 

materials in cement kilns. These include alternative fuels (e.g., scrap paper/wood, 

petroleum refinery spent catalyst and CSOS) and alternative raw materials (e.g., spent 

foundry sand, steel slag) used in cement clinker production. These materials are generally 

termed “alternative fuels and raw materials” (AFR).

b

 The benefits of using alternative fuels 

in the cement industry include: 

 Reduces the use of non-renewable fossil fuels such as coal as well as the 

environmental impacts associated with coal mining; 

 Contributes towards a lowering of emissions such as greenhouse gases by replacing 

the use of fossil fuels with materials that would otherwise have to be incinerated 

with corresponding emissions and final residues; 

 Maximizes the recovery of energy from the alternative fuel material. All the energy 

is used directly in the kiln for clinker production. It also maximizes the recovery of 

the non-combustible part of the alternative fuel material and eliminates the need 

for disposal of slag or ash, as the inorganic part substitutes raw material in the 

cement.6

The benefits of using alternative raw materials in the cement industry include the 

elimination of the need to dispose of the materials in landfills and avoidance of air 

emissions and other environmental impacts of production and transport of virgin (mined) 

raw materials. 

Industrialized countries have utilized AFR successfully for more than 20 years. However, 

the cement industry in the U.S. lags behind several countries in the percentage of thermal 

energy substituted by AFR, as shown in Table 1. 

Table 1: Share of AFR in Total Fuel Demand in the Cement Industry of Selected Countries

Country Percentage of thermal 

energy substituted by AFR

Year

France 32% 2003

Germany 42% 2004

Norway 45% 2003

Switzerland 47% 2002

United States 25% 2003

Source: CEMBRUREAU, SINTEF, as presented in The GTZ-Holcim Private Partnership, Guidelines 

on Co-Processing Waste Materials in Cement Production, p4, 2006.

 

b

The term “co-processing” is also use when discussing alternative fuels. Co-processing means the 

substitution of primary fuel and raw material by alternative fuels and raw materials in industrial 

processes. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

20

The study was conducted to refine our understanding of the challenges and opportunities 

for use of these materials by conducting material-specific analyses.c The study focused on 

the following:

 Technical Issues

 Cost Issues

 Regulatory Issues

 Supply/Logistics Issues

 Trends Analysis

 Emerging Issues/Materials

This report is the more detailed follow-up to the SSP report, Beneficial Reuse of Industrial 

Byproducts in the Gulf Coast Region, February 2008; see p. 15. Section 3.1 of that report 

discussed coal combustion byproducts, iron and steel manufacturing byproducts, and use 

of alternative fuels from other industries within cement production. The report noted a 10 

year trend in increased AFR use, and found that development of innovative and 

proprietary technologies “can lower barriers to beneficial reuse for technology owners, but 

may create barriers to beneficial reuse by other facilities” in the Gulf Coast Region (p. 26).

This finding is specific to the Gulf Coast Region and may be less of an issue in other 

regions of the U.S.

The scope of the study was limited because of budget constraints. Therefore a limited 

number of materials (initially four) were selected for analysis in the study and a limited 

number of contacts were made with cement plant contacts, regulatory agency contacts, 

and beneficial use material suppliers. These initial contacts identified substantive issues 

related to other materials and identified a number of emerging issues, so the scope of the 

study expanded from the initial four prioritized materials to a larger number of materials. 

An initial objective of the study was to conduct comparative cost analyses of the use of 

beneficial use materials. However, research conducted for this study did not produce 

sufficient economic data set to conduct detailed economic analysis for any of the 

materials. Cement plant contacts and beneficial use material suppliers were reluctant to 

provide detailed cost and economic data, even with assurance of Confidential Business 

Information (CBI) protection.

The case study summaries provide a general overview of the issues surrounding each 

beneficial use material without identifying specific cement plants. Appendix A contains a

more detailed discussion of the case studies.

Recommendations for further actions are based on conclusions and observations

concerning beneficial use materials supply and demand and cost, technical, and regulatory 

issues. Potential health effects of beneficial use of materials is outside of the scope of this 

report; however, the use of AFR at cement kilns would be subject to the full suite of safety, 

health, environmental, and transportation regulations applicable to any commercial fuels 

 

c

This report also serves as a continuation of the EPA, SSP report, Beneficial Reuse of Industrial 

Byproducts in the Gulf Coast Region, February 2008. Section 3.1 of that report discusses trends, 

drivers, and barriers to beneficial reuse in the Cement Manufacturing sector.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

21

and raw materials used at those locations. The potential for health effects will need to be 

considered in evaluating and implementing recommendations for further actions. 

Potential public perception and associated public communications issues related to 

beneficial use of materials are also outside of the scope of this report. 

The major sections of this report are organized as follows:

 Section 2 provides the background for the study;

 Section 3 outlines the beneficial use materials prioritization methodology, criteria, 

and results, and study methodology; 

 Section 4 provides case study summations;

 Section 5 provides conclusions;

 Section 6 provides recommendations and potentials for further actions by cement 

plants, suppliers, and federal and state regulatory agencies;

 Appendix A includes the detailed case studies for the beneficial use materials; and

 Appendix B provides information for the cement plant contacts, regulatory agency 

contacts, and other contacts for the study.

 Appendix C provides a description of cement kiln types.

2. Background

This section provides the background for the study and an overview of cement kiln 

technology and beneficial use materials. Kilns produce cement clinker, which is used to 

produce Portland cement, a binding agent that when mixed with water, sand, and gravel 

or crushed stone forms the rock-like mass known as concrete. Concrete, in turn, serves 

highway, commercial, and residential construction projects. Limestone and other 

ingredients, including material that is aluminous, ferrous, and siliceous, are placed into a 

kiln where a thermochemical process occurs to make cement clinker. The cement clinker 

is mixed with additives (e.g., gypsum) to make Portland cement. 

The U.S. Cement Manufacturing sector is concentrated among a relatively small number 

of companies; many U.S. cement plants are owned by, or are subsidiaries of, foreign 

companies. Together, 10 companies accounted for about 80 percent of total U.S. cement 

production in 2005.7 California, Texas, Pennsylvania, Florida, and Alabama are the five 

leading cement-producing states and accounted for about 48 percent of recent U.S. 

production.8 In 2007, about 91 million tons of Portland cement and about 4 million tons 

of masonry cement were produced at 113 plants in 37 States; total cement production 

capacity was about 127 million tons. Cement also was produced at two plants in Puerto 

Rico.9

2.1 Study Overview

The scope of this study is to identify potential barriers to increased use of AFR in cement 

kilns and to develop recommendations/further actions to address such barriers. Note that 

the scope of this study is limited to assessing the cost, regulatory, technical, and logistics 

and supply issues associated with use of AFR in cement kilns. 

Cement kilns use AFR to reduce operating costs and to reduce emissions of criteria air 

pollutants and greenhouse gases. The use of alternative raw materials by cement kilns 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

22

further avoids the need to mine and extract such materials and associated environmental 

and economic costs of mining and extraction. Alternative raw materials used as cement 

manufacturing ingredients (e.g., petroleum refinery spent catalyst, steel slag, spent 

foundry sand) supplies specific necessary elements (e.g., iron, silica) to the raw mix, 

replacing the need for virgin fuels or mined materials. The need for alternative raw 

materials depends upon the composition of the primary raw materials (e.g., limestone 

chemistry) available to the cement kiln. In some cases, if the readily available raw 

materials are deficient in one or more elements, an alternative raw material may be 

needed to achieve the needed composition of the cement manufacture raw ingredient 

mix. 

Landfill issues are also important with respect to beneficial use of raw materials, for 

example, spent foundry sand and steel slag, in cement kilns. These alternative materials 

are used to replace mined (virgin) materials. Disposal of alternative raw materials in 

landfills does not represent effective management of the potential raw material value of 

the materials, does not reduce the consumption of mined materials, and results in the 

unnecessary utilization of landfill capacity. 

An important component of the beneficial use of AFR as alternative fuels in cement kilns 

is the management of the energy content of the materials. Some of the materials 

addressed in this study, for example, scrap tires and biosolids, have substantial energy 

content and can be processed for energy recovery in cement kilns, but these materials can 

also be disposed of in landfills. These alternative fuels are used by cement kilns to replace 

conventional fossil fuels (e.g., coal, petroleum coke). Disposal of materials having calorific 

value in landfills does not represent effective management of the energy content of the 

materials, and reflects a lack of recognition that these materials have calorific value (BTU 

per pound). Conversely, use of alternative fuels in cement kilns avoids utilization of 

landfill capacity, and also represents effective management of the energy content of the 

materials and reduces the consumption of conventional fossil fuels. Use of alternative fuel 

materials also reduces emissions of greenhouse gases (carbon dioxide,) particularly where 

the alternative fuel material is a “carbon neutral” material such as biosolids. Also, 

utilization of alternative fuels in cement production results in the destruction of the 

materials in the manufacture of the clinker. Disposal of materials in landfills does not 

result in the destruction of the material, and therefore landfilling of materials may pose 

future liabilities that would not exist if the materials were destroyed in a cement kiln.

2.2Cement Kiln Technology

Rotary kilns are designed to produce clinker through the intense heating of raw materials, 

as described above. There are four basic types of cement kilns: (1) long wet kiln process, 

(2) long dry kiln process, (3) preheater kilns, and (4) preheater/precalciner kilns. 

The two primary kiln designs are the wet and dry processes. The number of wet process 

and dry process kilns operating in the U.S. is shown in Table 1. The primary difference 

between the various processes involves the state of the materials when entering the kiln. 

For instance, a kiln in a wet process plant must provide enough energy to evaporate the 

extra water used in the process. Additional discussion of cement kiln design and cement 

production technology is included in Appendix C.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

23

Table 2. Wet and Dry Kilns in the U.S.

Year Wet Kilns Dry Kilns Both

1998 34 74 2

1999 34 75 2

2000 32 77 2

2001 28 77 6

2002 27 80 3

2003 26 80 4

2004 24 80 5

2005 23 81 4

Note: Wet Kiln and Dry Kiln counts do not include kilns that are identified 

as “both” wet and dry in the USGS Mineral Yearbook.

Source: USGS Mineral Yearbook – Cement, 1998-2006

In long wet process kilns, raw materials are conveyed into the kiln in the form of a slurry 

with water. The water is evaporated in the kiln using heat from combustion of fuels. Heat 

to promote the chemical reaction of the raw materials to produce cement clinker is also 

provided by fuel combustion. Because evaporating the water in the raw material slurry 

requires energy, wet process kilns use more energy per ton of cement clinker produced 

than other kiln designs, and wet process kilns are typically longer than dry process kilns. 

In long dry process kilns, raw materials are introduced into the kiln with less water than 

wet kilns, but the device continues to rely upon convection heating in a horizontal 

cylinder which is less energy efficient than heating in a tower. A preheater kiln introduces 

raw materials with much less water than wet kilns and uses a vertical tower to transfer 

heat to raw materials taking advantage of heats tendency to rise to more effectively 

transfer energy. A precalciner kiln introduces raw material with much less water than wet 

kilns, uses a vertical tower to transfer heat to raw material, and uses a direct fuel to raw 

material heat transfer in the vertical tower to further improve heat transfer. 

All of these systems may use variations on the placement of burners and the recycle of 

waste heat to improve energy transfer to the raw materials. A typical 

preheater/precalciner type dry process kiln uses approximately one-third as much thermal 

energy as a typical wet process kiln (approximately 3.0 MMBTU per ton of clinker 

produced). Cement companies have been replacing their wet process kilns with dry 

process kilns. As of 2008, approximately 80 percent of all cement kilns operating in the 

U.S. were dry process kilns (of all types). 

Raw materials that are conveyed into kilns to produce clinker include: 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

24

 Clay

 Granulated (and other) blast furnace slags

 Ferrous materials

 Fly ash (and other ash)

 Lime

 Limestone

 Natural rock (and other) pozzolans

 Sand

 Sandstone

 Shale

 Steel (and other) slags

2.2.1 Cement Production 

While various processes exist, the kilns are generally horizontal, inclined rotating 

cylinders that are internally fired. The cylinder’s diameter can be up to 25 feet, is installed 

at a 3 to 4 degree angle, and rotates 1 to 3 times per minute. Rotary kilns run 24 hours a 

day, and are typically stopped only for a few weeks per year for essential maintenance. 

The raw material always enters into the upper end of the kiln, moves down the cylinder 

against a flow of hot gases and toward the lower end of the cylinder containing a flame. 

The dry, calcined material then enters a sintering zone where combustion gas reaches a 

temperature of 1800° to 1980° Celsius (C), and becomes clinker.10

A kiln serves several purposes, acting as a chamber for fuel combustion, a flue for gases, a 

conveyor for solids, a calciner (driving off carbon dioxide from the calcium carbonate), a 

mixer for the raw feed, and a host for chemically transforming feed into clinker.

Cement clinker is the primary ingredient in cement. Cement clinker production data for 

1990 through 2006 is shown in Table 2.11 As shown, U.S. cement clinker production has 

increased 37 percent from 1990 through 2006.

Table 3 U.S. Clinker Production

Year Clinker Production (1,000 

metric tons)

1990 64,355

1995 71,257

2000 79,656

2001 79,979

2002 82,959

2003 83,315

2004 88,190

2005 88,783

2006 88,453

Source: USGS Mineral Yearbook – Cement, 1992-2006

2.3Alternative Fuels and Raw Materials (AFR)

Cement manufacturers using AFR in kilns can achieve reduced energy costs and reduce 

criteria pollutant and greenhouse gas emissions. Considering the increasing cost of coal, 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

25

petroleum coke, and other conventional fuels used in cement production, there is an 

increasing incentive for cement companies to identify new sources of alternative fuels. 

Data for the utilization of conventional and alternative fuels in cement production are

shown in Table 3 in mass units and heat (BTU) units. Table 4 provides data for the 

calorific value of conventional and alternative fuels.d

There are important differences between cement manufacturing processes with respect to 

the beneficial use of AFR that are related to materials handling. For wet process kilns, and 

long dry kiln systems, for example, the primary means of introducing fuels into the 

process is directly into the front or lower end of the horizontal rotary kiln, at 

approximately the same location as the primary fuels (e.g., coal, petroleum coke). Some 

AFR may be introduced by penetrating the rotary kiln shell with introduction systems, but 

these locations can only supply a portion of the systems inputs. For example, alternative 

fuels introduced into the cement kiln at replacement rates greater than 50 percent would 

need to be conveyed into the kiln in the same general manner as the primary fuels are 

conveyed into the kiln, and would need to be in a physical form compatible with the kiln 

fuel handling system. An example of a system that penetrates the rotary kiln shell is a

scrap tire burner or solid waste container burner. Whole scrap tires or containerized or 

bundled energy bearing waste can be dropped into a horizontal rotary kiln through a 

chute and gate mechanism installed in the midpoint of the kiln (mid-kiln entry). 

 

For a preheater/precalciner-type dry process kiln, however, alternative fuel can be 

introduced either into the front end (lower end), and back end (upper feed shelve end) of 

the horizontal rotary kiln or into the systems vertical tower. This enables a broader range 

of alternative fuel characteristics to be introduced into the process. 

Care must be taken to introduce AFR at a locations in the system where complete 

combustion will occur or where appropriate chemical reactions will occur. The 

introduction location’s temperature, turbulence, oxygen, and time at conditions must be 

adequate to completely combust organic compounds, whether in the fuel, or contained in 

the raw materials (e.g., spent foundry sand). For raw materials the introduction location 

must allow adequate time for the materials chemical species to react in the manufacture 

process. For example a particular introduction point in a kiln system may allow too short 

a residence time to facilitate a fuel or raw material reaction. As such some dry kilns may 

require the use of tire chips, rather than whole tires because the chip has more surface 

area per mass and can react more quickly. 

Table 4: Energy Derived from Fuels Used in Cement Production

Fuel Type Quantity Used in 

Cement 

Production

Btus (billions) Used in Cement 

Production

Coal 9,997,231 tons 226,539.64 64.05%

Petroleum Coke 2,560,737 tons 74,900.71 21.18%

Natural Gas 12,723 million cu. ft. 12,939.29 3.66%

Middle Distillates 20,766,405 gallons 2,875.66 0.81%

Residual Oil 3,534,995 gallons 523.99 0.15%

 

d Note: The terminology used in this section and in Table 3 reflects the terminology used in the Portland 

Cement Association U.S. and Canadian Labor-Energy Input Survey (2006).
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

26

Gasoline 1,485,385 gallons 185.61 0.05%

LPG 950,379 gallons 81.81 0.02%

Waste Oil -- 1,008.72 0.29%

Waste Solvents -- 14,026.48 3.97%

Tire Derived Fuel -- 12,622.12 3.57%

Other Solids -- 2,686.92 0.76%

Waste -

Miscellaneous

5,311.63 1.50%

Source: PCA, U.S. and Canadian Labor-Energy Input Survey 2006e

Table 5: Lower Heating Value (LHV) of Conventional and Alternative 

Fuels

Fuel Type Btu per Pound Notes

Coal 11,300

Petroleum Coke 14,600

Paint Residues 7,000

Plastics 18,700 Polyethylene

12,000 Mixed non-chlorinated

Refuse-derived Fuel 6,500-7,000 Post-processing

Scrap Carpet 7,300 – 12,000 Nylon; Polypropylene

12,000 – 15,000 Post-processing

Scrap Tires 14,000 Tire-derived fuel

Automobile Shredder Residue 7,000 Pre-processing

10,000 Post-processing

CSOS 8,000 - 9,000 Centrifuged

Biosolids 7,000-8,000 Class A Dry

Paper/Cardboard 8,500 Dry

Sawdust 7,000 Dry

Wood 6,500 – 7,500 Dry

Engineered Fuel 10,000 [Wet Kiln Fuel]

6,500-8,000 [Dry Kiln Fuel]

Sources: Cement Industry Contacts; Murray, A.E., and Price, L., 2008.12

2.4 On the usage of the Term “Waste”

Beneficial use of industrial materials (referred to in the cement sector as coprocessing) 

involves transferring industrial byproducts from one industrial sector to another. Such 

transfers can reveal differences in perspectives between industry sectors concerning the 

definition of the industrial byproducts involved. Industrial byproducts have historically 

been referred to as “wastes,” even in cases where such products are recovered, rather than 

disposed of, and used as alternative fuels or alternative raw materials. “Waste oil,” which 

may be burned for energy recovery, is one example of such terminology. Both the cement 

industry and other industry sectors have adopted the terminology “alternative fuels and 

raw materials” (AFRs) to refer to industrial byproducts used as alternative fuels and as 

 

e

 This table contains the terminology of fuels used in the PCA U.S. and Canadian Labor-Energy Input 

Survey, 2006. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

27

alternative raw materials, however these materials are still referred to as “wastes” in 

cement sector and other industry sector documents. For example, the Portland Cement 

Association (PCA) Annual Labor and Energy Report 13 refers to “waste, oil,” “waste,

solvents,” and “waste, other solids” as fuel type categories, and the U.S. Geological Survey 

Minerals Yearbook for Cement refers to “liquid waste” as a fuel type category. 14 Other key 

documents that use the term “waste” in this context include EU Directive 94/67/EC, and 

WBCSD Cement Sustainability Initiative (CSI) “Guidelines for the Selection and Use of 

Fuels and Raw Materials in the Cement Manufacturing Process Cement Sustainability 

Initiative” (December 2005).

The generators of industrial byproducts (e.g., petroleum refineries) may be more inclined 

to refer to these industrial byproducts as “raw materials,” “feedstocks,” or “products” than 

are the users of the industrial byproducts (e.g., cement kilns). This is in part because the 

cement sector and other industry sectors have historically been paid fees to accept such 

“wastes” from generators, while the petroleum refineries and other industrial byproduct 

generators have been paid a fee to deliver their facilities “products” to customers. More 

recently, suppliers of alternative fuel to cement kilns, including cement company whollyowned subsidiaries and private companies, have adopted terms such as “engineered fuel” 

when referring to fuels derived from many different industrial byproduct streams. The 

preparation process used to produce this fuel adjusts for the technical and administrative 

specifications of cement, and guarantees that environmental standards are met

independent of the specific industrial byproduct streams used in its production.

15

Also note that the terminology of “waste” and specific regulatory definitions of “waste” 

(e.g., “hazardous waste;” “solid waste;” “municipal solid waste”) date back several decades. 

The term “waste” has therefore come into general usage as applied to industrial 

byproducts even in cases where the material is not defined by regulation as a waste. 

EPA generally has regulated units that process materials (waste or otherwise) for energy 

recovery under CAA 112 MACT standards, such as the Portland Cement Kiln MACT, 

Industrial Boiler MACT, and the Pulp and Paper MACT. However, the DC Circuit recently 

vacated and remanded two EPA rules promulgated under the CAA – the Commercial and 

Industrial Solid Waste Incineration (CISWI) definitions rule, issued under section 129 of 

the Act, and the Boiler MACT, issued under section 112 of the Act. The court concluded 

that EPA erred by excluding units that combust solid waste for purposes of energy 

recovery from the CISWI rule and including such units in the Boiler rule. 

In response to the court’s decision, EPA is currently examining the use of various materials 

by industries, including the cement industry, and is in the process of conducting a 

rulemaking to determine which materials are solid wastes under RCRA, subtitle D. EPA 

also is establishing new standards under both 112 and 129 for the various units subject to 

each section, as the community of units regulated under each section will change as a 

result of the ruling. A separate MACT Standard for hazardous waste combustors (HWCs) 

applies to cement kilns that burn hazardous waste. In general, cement kilns operate 

under Title V Operating Permits issued by state regulatory agencies implementing Clean 

Air Act programs.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

28

Specific types of “waste” are defined in the Resource Conservation and Recovery Act 

(RCRA) and other statues and regulations. For example, RCRA Hazardous Waste Code 

K170 waste is defined as: Clarified Slurry Oil (CSO) storage tank sediment and/or in-line 

filter/separation solids from petroleum refining operations.16 This material is referred to 

in this document as Clarified Slurry Oil Sediments (CSOS). This material is categorized as 

a “RCRA hazardous waste.” 

Lastly, EPA’s Office of Solid Waste and Emergency Response (OSWER) is currently 

considering organizational changes that, among other things, reflect the growing trend to 

view waste management as resource recovery and reuse opportunities, as appropriate. The 

cement and other industries are finding new ways to use materials that have historically 

been discarded or treated as wastes. Industrial facilities are reusing byproducts or waste 

materials in their own operations or sending them elsewhere for reuse as a substitute fuel 

or raw material. EPA values such beneficial reuse, and recognizes the many opportunities 

associated with converting waste products into valuable commodities.

The term “waste” in this document is not intended to connote any regulatory classification 

except when the term “waste” is used in phrases such as “RCRA hazardous waste;” “solid 

waste;” and “municipal solid waste,” which are terms defined in EPA regulations. Other 

uses of the term “waste” (e.g., “waste oil”) in this document are derived directly from the 

terminology used in the source documents (e.g., the PCA Labor and Energy Report; the 

USGS Cement Minerals Yearbook) and do not and are not intended to connote any 

regulatory classification of the material. 

3. Beneficial Use Materials Prioritization

This section describes the beneficial use material prioritization, selection criteria, and 

results, and provides the methodology and rationale for selecting beneficial use materials 

for further material-specific analysis. 

3.1 Development of Materials Prioritization List and Criteria

The study that gave rise to this initiative was the Beneficial Use of Industrial By-Products in 

Cement Kilns: Analysis of Utilization Trends and Regulatory Requirements, April 2005. 

This study was prepared to support the EPA/PCA Beneficial Use of Alternative Fuels and 

Materials Workshop organized by SSP and PCA and conducted in July 2005. The objective 

of the EPA/PCA Workshop was to initiate a discussion of regulatory and economic drivers 

and barriers among cement kiln operators, beneficial use material generators, and 

regulators. Ten beneficial use materials were evaluated in the ICF International April 2005 

Draft Beneficial Use Report and discussed at the July 2005 EPA/PCA Workshop.17 These 

include:

 Steel Slag;

 Spent Foundry Sand;

 Coal Combustion Products (fly ash);

 Scrap Tires;

 Scrap Paper/Wood;

 Construction and demolition (C&D) Debris;
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

29

 Waste/Off-Specification Paint and used non-hazardous used oil;

 Refinery Spent Catalyst and Clarified Slurry Oil Sediment;

 Spent Aluminum Potliners; and 

 Animal Meal (rendering plant by-products)

The ten materials evaluated in the Draft Beneficial Use Report were prioritized based on 

the following criteria: 

 Amount of the Beneficial Use Material Generated in the U.S.;

 Amount of the Material Beneficially Used in Cement Kilns in the U.S.;

 Anticipated Availability of Economic Data; 

 Alternative Beneficial Uses and Likelihood of Disposal; and 

 Regulatory Framework and Disposal Methods

In addition, further discussion of the prioritization criteria with the PCA focused on the

identification of a subset of materials for further analysis. Specifically, it was agreed that 

the four materials selected for further analysis should include three that are “commonly 

used” (i.e., non-hazardous waste) materials and one “challenge material,” potentially a 

listed RCRA hazardous waste material. Also of value in considering materials for study in 

this report was the SSP report, Beneficial Reuse of Industrial Byproducts in the Gulf Coast 

Region, February 2008.

18

3.1.2 Study Methodology

Cement plants were selected for this study to provide a range of beneficial use materials 

being used, a range of kiln types, and a range of geographic location. The types of 

beneficial use materials that each cement plant uses and the type of cement kiln was 

identified from the Portland Cement Association U.S. and Canadian Labor and Energy 

Report (2006).

Data for each cement plant included in the 2006 PCA Labor and Energy Report were

organized in a spreadsheet by kiln type (wet kiln, dry kiln, preheater, precalciner); and by 

primary fuels and alternate fuels (coal, petroleum coke, fuel oil, natural gas, and “waste” 

fuels including “Waste, Oil;” “Waste, Solvents;” “Waste, Other Solids;” and “Waste, 

Miscellaneous” as separate general categories of “waste); and primary raw materials used 

(including spent foundry sand, steel slag, and “refinery catalyst,” which could include 

spent FCC catalyst waste, among the raw material subcategories). When citing data from 

the PCA Labor and Energy Report, this study uses the terminology used in the underlying 

Report. Several of the cement plants that were identified as using “waste” as primary fuel 

were selected for the study, and several of the cement plants that reported using spent 

foundry sand, steel slag, or refinery spent catalyst were also selected for the study. No 

specific data concerning scrap paper/wood was included in the reference (this would be 

listed under “other” in the data) so preliminary research using public data sources was 

conducted to investigate utilization of C&D debris by cement kilns. Several of the cement 

kilns that reported using “other” fuel were selected for the study.

In August 2007, topics for discussion were developed for the initial prioritized beneficial 

use materials of spent foundry sand; steel slag; scrap paper/wood; C&D debris; and 

refinery spent catalyst and CSOS. The materials were developed as “interview guides” for 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

30

conducting telephone interviews with the cement plant and regulatory agency contacts. 

Specific areas of discussion with the cement plant contacts included the types of beneficial 

use materials utilized; the sources of the materials; past and anticipated future trends in 

the available supply of the material and in the cement plant’s utilization of the material, 

and technical and regulatory issues associated with utilization of the material. The 

technical and regulatory issues addressed included the quality of the available material; 

materials handling and materials processing requirements; potential effects of utilization 

of the material on cement clinker quality or on kiln environmental performance; and 

requirements for environmental permitting and performance testing prior to using the 

material. 

Cement plant contracts were identified in coordination with the principal PCA contact 

and members of the PCA Energy and Environment (E&E) Committee in September 2007, 

and the topics for discussion were sent to cement plant contacts. Telephone interviews 

were conducted with the cement plant contacts using the topics for discussion as

interview guides between November 2007 and March 2008. The initial list of cement 

plants to be contacted for the study expanded as the study was being conducted. In some 

cases the contact for one cement plant provided contact information for another of that 

company’s cement plants, in order to provide additional information for a specific 

beneficial use material.

PCA and EPA also coordinated a meeting with API representatives in November 2007 at 

API Headquarters to discuss technical and regulatory issues related to clarified slurry oil 

solids issues. Several petroleum refiners represented at the meeting are generating CSOS 

for beneficial use in cement kilns or other onsite or offsite management. Telephone 

interviews were conducted with these petroleum refinery contacts in December 2007 and 

January 2008. 

State and local regulatory agency contacts were identified through the telephone 

interviews with cement plant contacts and petroleum refinery contacts. Telephone 

interviews with agency contacts were conducted between November 2007 and March 

2008. Agency contacts were identified specifically to obtain information concerning the 

site-specific state and local regulatory issues, permitting and performance testing issues, 

public perception issues, and related issues surrounding each beneficial use material. 

Agency contacts were also interviewed to research various state-level and local-level 

economic programs that have been established to promote the beneficial use of materials. 

In addition to the four initially prioritized materials, alternative fuel beneficial use 

materials were identified for material-specific analysis and development of “emerging 

issue” case studies based on interviews with cement plant contacts and state and local 

regulatory agency contacts. These include:

 Wastewater Treatment Sludge (biosolids)

 Plastics 

 Scrap Tires

 Automobile Shredder Residue (ASR)

The rationale for including these additional materials is described below.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

31

The interviews conducted identified economic, technical, and regulatory barriers to 

increased use; this information used to develop material-specific case studies. These case

studies are included in Appendix A. The case studies identify specific recommendations 

and further actions to address identified barriers. The further actions/recommendations 

are integrated with the further actions and recommendations for the cement sector 

identified in the SSP Beneficial Reuse of Industrial Byproducts in the Gulf Coast Region,

February 2008.19

3.1.3 Alternative Fuels Methodology

SSP contacted cement plant contacts, regulatory agency contacts, and suppliers 

concerning use of alternative fuels in cement kilns. EPA initiated research by contacting 

the cement plant contacts identified through discussions with the PCA. The discussions 

initially focused on prioritized materials, but led to the identification of “emerging 

material” alternative fuels, either in use or being investigated by the cement plants. 

The topics of discussion expanded as the telephone interviews progressed, including areas 

such as cement companies’ business approach towards alternative fuels (e.g., some cement 

companies have a general policy that their cement plants do not accept hazardous waste) 

and corporate-wide as well as plant-specific issues and policies. In some cases follow-up 

calls were made to specific cement plant contacts to obtain additional information 

concerning issues that arose in other interviews or to obtain additional cement plant 

contacts to discuss the use of, or investigation of, emerging materials. 

Cement plant contacts also identified state or local regulatory agency contacts responsible 

for permitting for their plants and other regulatory agency contacts (e.g., regulatory 

agencies responsible for management of state scrap tire management programs or 

programs to support beneficial use of materials). Cement plant contacts and regulatory 

agency contacts identified suppliers of alternative fuels, including contacts at the cement 

companies’ wholly-owned subsidiaries responsible for materials sourcing and also 

independent alternative fuel suppliers. 

SSP also conducted research into specific regulatory issues concerning alternative fuels 

(e.g., the regulatory status of CSOS and ASR) and conducted meetings with SSP

counterparts for other Industry Sectors to obtain additional perspective on sector-specific 

issues. 

3.1.4 Alternative Raw Materials Methodology

The methodology for alternative raw materials was similar to that for alternative fuels 

except that specific third-party materials suppliers were not identified by the cement plant 

contacts. Therefore, no third-party suppliers were interviewed. The wholly-owned 

subsidiaries responsible for alternative fuels material sourcing for cement plants also 

perform sourcing for alternative raw materials. 

3.2Criteria Application and Prioritization Results

The Preliminary Prioritization of Beneficial Use Materials for Market Analysis prepared in 

January 2006 provided an initial prioritization of the beneficial use materials for further 

analysis. Portland Cement Association Briefing Materials were prepared in January 2007, 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

32

and the materials prioritization process and preliminary selection of four materials was 

discussed with the principal PCA contact at a meeting in February 2007. The selection of 

four materials for development of case studies were reviewed and confirmed by PCA’s E&E 

Committee through an informal working group formed in June 2007 of PCA E&E 

Committee members identified by the principal PCA Contact. The preliminary 

prioritization analysis was prepared and discussed with the members of the PCA E&E 

Committee. From the preliminary analysis and subsequent discussions, spent foundry 

sand, steel slag, scrap paper/wood, C&D debris, and refinery spent catalyst and CSOS were 

selected for further analysis in this report. Application of the prioritization criteria and 

selection of materials is described further in this section.

3.2.1 Spent Foundry Sand

Spent foundry sand was selected as a material for further analysis based on the relatively 

large amount of this material generated and the relatively low amount used as raw 

material in cement clinker production. The industry consortium, Foundry Industry 

Recycling Starts Today (FIRST), notes that 6 to 10 million tons of spent foundry sand are 

discarded annually and are available to be recycled.20 As shown in Table 5, the American 

Foundry Society reported in their 2007 survey that almost 50 percent of the spent foundry 

sand generated is used as construction fill; use in cement production (a subset of the 

“other” category in the survey data) is relatively low, and use as landfill cover (a category 

not separately reported by the AFS) is relatively high. An objective of this study is to 

provide insight into utilization trends for spent foundry sand.

Table 6: Beneficial Reuses of Spent Foundry Sands According to

American Foundry Society Bench Marking Survey21

Beneficial Use Application Quantity Beneficially Used (Tons) / Percent

Construction fillb1,140,914 43.13%

Concrete 303,531 11.47%

Not specified/Other 292,928 11.07%

Road construction 144,288 5.45%

Top soil mix/horticulture 220,949 8.35%

Reuse at another foundryc48,426 1.83%

Asphalt 494,390 18.69%

Total: 2,645,427d100.00%

a. Based on 244 total respondents, or a 24 percent completion rate. Survey respondents had 

the option of selecting more than one beneficial use application. Beneficial use quantities 

have been extrapolated to reflect beneficial use in the entire metal casting industry. 

b. Construction fill includes both structural fill and flowable fill.

c. Spent foundry sand is transferred from one foundry to another for use in on-site 

construction projects or other application.

d. AFS excludes landfill cover as a beneficial use application from the total beneficial use 

quantity (2,645,427 tons).

3.2.2 Steel Slag

Steel slag was selected as a material for further analysis based on the relatively large 

amount of this material generated and recent trends concerning use as a raw material in 

cement clinker production. In 2006, iron and steel slag sales in the U.S. totaled 20.3 
                       

                              

                           

                                

                               

 

 

                       

                          

                           

                          

                          

                          

                                

Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

million metric tons.22 As shown in Figure 1

23, use of steel slag in cement clinker

production peaked in 2000 and then declined, showing a slight increase from 2004 to

2005. An objective of this study is to provide insight into utilization trends for steel slag.

Figure 1. Utilization of Iron and Steel Sector Slag in Cement Clinker Production in the U.S.

(1999‐2005)

0 

200 

400 

600 

800 

1,000 

1,200 

1999 2000 2001 2002 2003 2004 2005 

(thousand metric tons)

 Steel slag Other blast furnace slag 

Other slags Granulated blast furnace slag 

3.2.3 Scrap paper/wood and C&D debris

Scrap paper and wood and C&D debris were selected as general material categories for

further analysis specifically to provide a focus on C&D debris.  An objective of this report

is to provide insight into the potential for use of C&D debris and also scrap paper/wood in

cement clinker production.  The February 2008 Gulf Coast Region Beneficial Reuse Report

specifically focused on the potential for beneficial reuse of C&D debris generated when

tropical storms strike the Gulf Coast Region.  In 2002, 35.7 MMT of C&D debris wood was

generated, with 29.2 MMT potentially available for recovery; but, possibly only 2.7 MMT

was being actually recovered in new construction.24  Significantly larger amounts of C&D

debris wood are generated during tropical storm events.  C&D debris (i.e., C&D debris

containing wood) could be used as an alternative fuel in cement production.  While some

utilization of scrap paper/wood has been reported, cement plants have not historically

used significant quantities of alternative fuels derived from C&D debris in cement clinker

production.

One cement plant contact25 reported that the plant was offered C&D debris generated

from Hurricanes Katrina and Rita. However, the C&D debris (containing wood) was so

commingled with other types of C&D debris that the cement plant decided that the

material could not be feasibly processed into alternative fuel. Therefore they declined to

accept the material. Another cement plant contact26 reported that the plant uses wood,

including some segregated wood material from C&D debris yards. This wood material is

preprocessed by the C&D debris yard prior to being sent to the cement plant. The cement

33
 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

34

plant itself does not have equipment to process C&D debris. No other cement plant 

contacts indicated that the cement plants were using wood or other alternative fuels 

generated from C&D debris. 

3.2.4 Refinery spent catalyst and clarified slurry oil sediments

Refinery spent catalyst and clarified slurry oil sediment (CSOS) were developed and 

selected as materials for further analysis specifically to provide a focus on CSOS, a RCRA 

listed hazardous waste generated by petroleum refineries. Clarified slurry oil (CSO) is 

generated from fluidized catalytic crackers (FCCs) at petroleum refineries. Some of the 

FCC catalyst is entrained in the CSO. These fines settle out of the CSO as solids, and these 

solids periodically need to be removed from the CSO storage tanks. These solids, referred 

to as CSOS, are listed as RCRA hazardous waste (waste code K170). A single petroleum 

refinery may generate on the order of one million pounds (500 short tons) of CSOS per 

year from CSO tank cleanouts (but the yearly generation rates can be highly variable and 

may be significantly higher than that quantity in any given year, depending on tank 

cleanout schedules); a substantial portion of this CSOS is generated in Texas and 

elsewhere in the Gulf Coast Region, because of the high concentration of petroleum 

refineries in the region.

27

 The calorific value of CSOS varies depending upon how it is 

generated and processed. Refineries can process the CSOS to remove more, or less, of the 

oil contained in it. One refinery contact 28 reported that after processing the CSOS by 

centrifuge to remove oil, the calorific value of the CSOS is on the order of 8,000 to 9,000 

BTU per pound; though, as noted above, it can vary above or below that depending on 

how it is generated or processed prior to shipment.

Research conducted for this report identified several cement kilns that are using CSOS as 

an alternative fuel, however use of this material is limited to the relatively small number of 

cement kilns (18) that have RCRA hazardous waste combustor permits, and therefore this 

material was categorized as a “challenge material” for this report. An objective of this 

report is to assess regulatory, technical, and cost barriers associated with generation of 

CSOS and use as an alternative fuel in cement clinker production.

As shown in Tables 6 and 7, generation and management of K170 waste varies by year and 

the amount of K170 waste managed by offsite energy recovery decreased from 2001 to 2005 

(the most recent data available through the EPA hazardous waste reporting system). In 

2005 only 24 tons of K170 waste was reported as being managed through offsite energy 

recovery at a cement kiln, while approximately 16,000 tons of K170 waste was managed 

through other methods. Five cement plants accepted K170 waste for energy recovery in 

2001, and only one in 2003 and in 2005. 

Note that the amount of CSOS that is generated and managed on site at refineries is not 

reported into the EPA hazardous waste reporting system. Refinery contacts 29 indicated 

that refineries frequently manage their CSOS on site under an available regulatory 

exclusion, despite the fact that on site management may be more expensive, in part to 

enable the refineries to avoid having to classify the materials as hazardous waste when 

shipped offsite. Therefore, the data in Tables 7 and 8 do not reflect the amount of CSOS 

that is actually available for beneficial use in any given year. Table 930 contains API data 

with a summary of K170 waste generation that includes only hazardous waste streams with 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

35

the primary waste code of K170.f Some hazardous wastes can be assigned more than one 

RCRA hazardous waste code. 

Table 7: Annual Generation and Management Methods of K170 Hazardous Waste 

(Clarified Slurry Oil Sediments) 

Reporting 

Year

Number 

Generators 

K170 Waste

Tons of K170 

Waste Managed 

through Energy 

Recovery

Tons of K170 

Waste Managed 

through Other 

Methods

Total Tons of 

K170 Waste 

Managed

2001 43 5,374 25,535 30,909

2003 37 2,080 30,327 32,408

2005 46 24 16,352 16,376

Source: EPA Hazardous Waste Reporting System, 2008

Table 8: Annual Disposition of K170 Waste (CSOS) Managed through Energy Recovery

EPA ID

Waste Management 

Facility Name

K170 Waste Quantity (in tons) Managed 

Through Energy Recovery

2001 2003 2005

ARD981057870 Rineco Chemical Industries 1.2

IND005081542 ESSROC Cement Corp 48.5

KSD980633259 Systech Environmental 2,445.3

MOD054018288

Continental Cement Co 

LLC 1,130.8 24.31

MOD981127319 Lone Star Industries Inc 131.0

SCD003351699 Giant Cement Company 698.1

TXD007349327 TXI Operations LP 1,194.0

TXD981053770 Duratherm Inc 1,382.1

FCCANADA3 Not Available 423.3

Total 5,374 2,080 24

Source: EPA Hazardous Waste Reporting System, 2008

 

Table 9: NAICS 32411 GM Forms, Management Code H050 and H061, Outlier and 

Mixed Waste Excluded

Reporting Year Number of 

Generators 

of K170 

Waste

Tons of K170 

Waste Managed 

through Energy 

Recovery

Tons of K170 

Waste Managed 

through Other 

Methods

Total Tons of 

K170 Waste 

Managed or 

Shipped

2001 37 9,734 14,330 24,064

2003 26 878 3,248 4,126

2005 35 3,284 5,954 9,238

Source: API (2008)31

3.2.5 Other Prioritization List Materials 

The other five materials on the prioritization list were eliminated from initial material 

prioritization based on various criteria. No cement kilns were identified as using either 

animal meal or spent aluminum potliners; these materials were eliminated from further 

 

f

 This table excludes a single waste stream of 175,013 tons reported in 2005 because it is an outlier related 

to soil remediation activities. The waste stream was described as “haz waste soils and sludges generated 

during RFI remedy” which was disposed in a landfill. According to the facility, this was a one-time event. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

36

consideration based on the anticipated lack of data concerning beneficial use. Similarly, 

the market for waste/off-specification paint is not well-developed; research conducted for 

this report identified one cement plant using latex paint solids as a raw material for 

clinker production. The cement plant mixes cement kiln dust with the latex paint solids

to facilitate the introduction of CKD into the kiln; the CKD/latex paint solids mixture is 

fed into kiln. This material is discussed as an “emerging material.” 

Non-hazardous used oil, coal combustion products, and scrap tires were not initially 

selected for further analysis because the infrastructure for collection and utilization of 

these materials is already well-developed, and because utilization of these materials in 

cement clinker production is already relatively high. Scrap tires were added back to the 

report scope for further analysis because many cement sector contacts identified emerging 

issues related to scrap tire management.32

Non-Hazardous Used Oils

In 2006, according to the PCA U.S. and Canadian Labor-Energy Input Survey, 65 of 97 

cement plants included in the survey reported using alternative waste fuels (with some 

plants reporting use of more than one type of alternative waste fuel). These included 48 

plants using scrap tires and 16 plants using non-hazardous waste oil.33 Non-hazardous 

waste oil includes used motor oil collected from commercial automobile service 

establishments, and used oils generated by industrial manufacturing facilities and other 

types of facilities.

Several cement plant contacts reported utilization of used (non-hazardous) oil as an 

alternative fuel. No trends data are available for used oil; however the overall amount of 

used oil and other liquid streams being used as alternative fuel in cement kilns, as 

reported by the USGS is trending up.gLiquid alternative fuel utilization in cement 

production was approximately 745 million liters in 1993, approximately 999 million liters 

in 2004, and approximately 1,470 million liters in 2005, the latest year for which the USGS 

has reported data.

34

 Note that the category of “liquid waste” as reported by the USGS 

includes used oils, off-spec oils, liquid hazardous waste, and other liquid alternative fuels. 

USGS reported that approximately 1 billion liters (approximately 900,000 metric tons) of 

used oil and other liquids were used as alternative fuels in cement kilns in 2004, while 

approximately 1.5 billion liters of used oil and other liquids were used in cement kilns in 

2005. 

Coal Combustion Products

Figure 2

35 illustrates the amounts of coal combustion products used in clinker production 

and cement production. National data from PCA for 2006 indicated that, of the 115 

operating Portland cement plants reporting in the PCA report, more than 50 plants used 

fly ash or bottom ash generated from electric power plants.36 This includes use of coal 

combustion products as a raw material in clinker production and use of coal combustion 

products as additives in cement production. The scope of this report includes coal 

 

g Note: The terminology used in this section reflects the terminology used in the U.S. Geological Survey 

Minerals Commodity Yearbook, Cement (2006).
                       

                           

               

                        

                           

                          

                         

                             

  

                       

 

                           

                           

                            

                           

                                  

          

                 

       

   

   

       

     

   

     

       

   

Note: Includes both raw materials fed into kilns and additives used in producing cement

Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

combustion products used as a raw material in the cement kiln, but not coal combustion

products used as additives in cement production.

In 2006, 124.8 million metric tons of coal combustion products were produced.37 The

amount of bottom ash and fly ash being beneficially reused in cement production has

actually been increasing faster than the amount of cement clinker produced. In 2005,

according to USGS data, cement plants used 4.2 million metric tons of coal combustion

products as raw materials in producing clinker, including fly ash, other ash, and other coal

combustion slags. 38

Figure 2. Coal Combustion Products Used in Producing Clinker and Portland Cement

0 

1,000 

2,000 

3,000 

4,000 

2001 2002 2003 2004 2005 

(thousand metric tons)

 Fly ash Bottom ash FGD Gypsum Boiler Slag 

Scrap Tires

RMA estimates that about 299 million scrap tires were generated in 2005, representing an

8‐fold increase in the percentage of scrap tires going into markets annually since 1990,39

Approximately 400,000 metric tons of scrap tires were used as alternative fuel in cement

kilns in 2005, according to USGS data. Table 8 illustrates the amount of scrap tires used as

alternative fuel in cement production.40

Table 10: Scrap Tires Used as Alternative Fuels in Cement Production

Metric Tons of Scrap Tires Used

Year Total Dry Kiln Plants

Utilizing Scrap

Tires (Out of total

Dry Kiln Plants)

Wet Kiln Plants

Utilizing Scrap Tires

(Out of Total Wet

Kiln Plants)

2002 304,000 210,000 (80) 94,000 (27)

37
 
Figure 3. Scrap Tires as Tire-Derived Fuel 

Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

38

2003 387,000 291,000 (80) 97,000 (26)

2004 377,000 312,000 (80) 66,000 (24)

2005 405,000 315,000 (80) 90,000 (23)

The use of scrap tires by cement plants has increased dramatically over recent decades: in 

1991 nine plants in the U.S. were using scrap tires and by 2001, 39 plants were using scrap 

tires for fuel.41 By 2005, 58 million scrap tires were used in 47 plants in the U.S. 42 In 

addition to calorific value, scrap tires also provide raw material content to the cement 

kiln. Iron is a necessary ingredient for clinker manufacturing. When scrap tires are used as 

an alternative fuel, approximately 250 kg Fe per ton of scrap tires is recovered, reducing 

the quantity of iron required from mined mineral sources. 

43

Figure 3 illustrates the overall trend in use of scrap tires as tire-derived fuel for energy 

recovery, including use in cement kilns. 44 Figure 4 illustrates that in 2005 approximately 

52 percent of scrap tires generated nationwide were used in energy recovery (including in 

cement kilns and in other energy recovery processes), and approximately 14 percent were 

disposed of in landfills.45 Cement kilns made up 38 percent of the tire-derived fuel market 

in 2005, according to data published by RMA.

46
Figure 4. Use of Scrap Tires in 2005 

Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

39

3.3 Emerging Materials 

Interviews with cement sector contacts and state and local regulatory agency contacts 

identified additional study materials for development of “emerging material” case studies. 

Issues identified for these emerging materials include limitations on supply, technical and 

logistics limitations, effects on plant air emissions, cost and regulatory issues related to 

landfill disposal, and other items identified by contacts.

3.3.1 Wastewater treatment sludge (biosolids) 

Biosolids are generated primarily from municipal wastewater treatment plants (WWTP).

In 40 CFR Part 503, EPA categorized biosolids as Class A or B, depending on the level of 

pathogenic organisms in the material. The classification of biosolids affects the feasibility 

of a cement plant to use the biosolids. Cement kilns may be limited to using only Class A 

biosolids both because of regulatory issues and materials handling issues. 40 CFR Part 503 

requires specific treatment processes and treatment conditions that must be met for both 

A or B classifications. Class A biosolids contain minute levels of pathogens. To achieve 

Class A certification, biosolids must undergo heating, composting, digestion, or increased 

pH that reduces pathogens to below detectable levels. “Class B” biosolids “may have low 

levels of pathogens which rapidly die-off when applied to soils, essentially becoming 

pathogen-free within a short period following application.” 47

 Class B biosolids have less 

stringent standards for treatment. After treatment to reduce moisture content, the 

calorific value of biosolids may range from 7,000-8,000 BTUs per pound. 

The North East Biosolids and Residuals Association (NEBRA) estimates that 16,583 

wastewater treatment facilities in the U.S. generate 7,180,000 dry short tons of biosolids 

that can be beneficially reused or disposed.48

 NEBRA conducted a survey of water 

treatment facilities and consulted existing data from sources such as EPA. The resulting 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

40

report estimates that about 3,300 of the largest facilities generate 92 percent of the total 

quantity of biosolids produced in the U.S. 

Several contacts reported that their companies have recognized that there is a large and 

continuously-generated supply of this material and that in many jurisdictions the material 

is accumulating on the POTW sites rather than being used. These contacts also indicated 

that their company’s investigation of biosolids as an alternative fuel is a proprietary issue 

for the company. Details of their investigations were therefore not disclosed.

Most biosolids generated nationwide are applied to land, and are not incinerated or 

burned for energy recovery in cement kilns. Some municipal wastewater treatment 

system operators have developed biosolids management programs that focus on land 

application rather than energy recovery. For example, The Sanitation Districts of Los 

Angeles County (CSDLAC) system, which operates the Joint Water Pollution Control Plant 

(JWPCP,) includes seven POTWs linked by a common sewer system serving 5 million 

people in Los Angeles County and treating 500 million gallons per day of wastewater. 

Because of the tremendous volume served by JWPCP, the County developed various ways 

to manage biosolids in the last several years. The four biosolids management practices 

include: land application, which accounts for 76 percent of the system’s biosolids; 

injection into a cement kiln, which accounts for another 12 percent of the biosolids and 

helps reduce the levels of nitrogen oxide (NOx) air emissions from the cement making 

process; composting, which has been moved off site to two privately operated facilities; 

and landfilling, which accounts for approximately 12 percent of the system’s biosolids.49

3.3.2 Plastics

Several cement plant contacts reported recently establishing use of plastics as an 

alternative fuel50 and others reported that they are investigating the feasibility of using 

plastics.51 In 2006, 29.5 million tons of plastics were generated from MSW and other 

sources.

52

 These materials included either plastic scrap from manufacturing processes or 

post-consumer plastics generated from MSW recycling programs. Cement plant contacts 

and regulatory agency contacts indicated that the principal issues associated with the use 

of plastics include identifying (generating) an adequate long-term supply of the material 

and ensuring that the material is “clean” and not commingled with the general MSW

stream or with other non-plastic materials. The material must be adequately segregated 

from the general solid waste stream to facilitate material handling and adequately

segregated from chlorinated plastics to ensure that chlorinated plastics are not included in 

the feed stream. Cement kilns need to limit the amount of chlorine feed to the kiln to 

maintain clinker quality. 53 Cement sector contacts reported that plastics, as generated by 

suppliers, have a calorific value similar to that of coal (approximately 12,000 BTU per 

pound).

3.3.3 Automobile shredder residue (ASR)

Automobile shredder residue was identified as an emerging material by the PCA E&E 

Committee Alternative Fuels and Raw Materials (AFR) subcommittee. Automobile 

shredder residue (ASR) contains the plastic and other non-metallic materials left after 

scrap automobiles are shredded, and can have a calorific value on the order of 10,000 BTU 

per pound after processing to remove residual metals and other non-combustible 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

41

materials. According to the Argonne National Laboratory, as of 2003, U.S. auto shredders 

generated about 5 million tons of ASR annually.54 Because of the lack of a cost-effective 

technology to recycle ASR, it is mostly landfilled; smaller amounts are incinerated. Scrap 

Magazine has estimated ASR generation at about 5.4 million tons per year.55 This is 

consistent with Steel Recycling Institute automotive recycling rates data. These data show 

that automotive recycling rates have been relatively consistent from 2003 through 2006.56

The PCA E&E subcommittee is investigating the potential use of this material as an 

alternate fuel in cement kilns. The PCA E&E subcommittee contact indicated that the 

calorific value of ASR after it is processed is similar to the calorific value of coal, but that 

because of Toxic Substances Control Act (TSCA) regulations that specifically categorize 

ASR as a “PCB Waste” most of the ASR generated is landfilled rather than burned for 

energy recovery.57 A recent study by the California Department of Toxic Substances 

Control (DTSC) included test data for ASR generated in California. The test results 

showed that the PCB content of disposed ASR generated by several California facilities 

averaged total PCB levels ranging from 16 to 82 ppm. 58 The California DTSC report 

indicated that modification of the TSCA classification definitions applicable to ASR may 

be needed to facilitate use of ASR as an alternative fuel in cement kilns. ASR can also 

contain copper and mercury (from mercury switches contained in scrap automobiles) and 

therefore ASR has the potential to affect air emissions from the cement kiln. Mercury can 

be emitted through the cement kiln stack, and copper, in combination with chlorine 

contained in cement kiln raw materials and fuels, can contribute to the formation of 

PCDD/PCDF emissions from the cement kiln stack. 

Argonne National Laboratory recently developed a “froth flotation” technology to separate 

ASR into higher value high-purity plastics. The technology is being evaluated by a 

consortium of automobile manufacturers.59 A full-scale demonstration project was 

conducted in Europe. 60, 61 Such treatment technologies may be a potential competitor to 

use of ASR as an alternative fuel in cement kilns. Boughton (2006) reported that 

automobile recyclers are also working on developing and applying technologies to 

improve the separation of materials in ASR and to improve its combustion characteristics 

with respect to cement kiln operation and environmental impacts. These include 

application of existing ASR density separation technologies to separate fine material (<1.2 

cm) from the ASR. This can reduce effects of the use of ASR on CKD characteristics and 

on air emissions. Boughton (2006) also reported that ASR has raw material value in 

addition to its fuel value, and noted that ASR contains silicates, calcium, aluminum, and 

iron. 

62

3.3.4 Carpet Scrap

One cement plant contact reported using scrap carpet generated from residential and 

commercial building carpet installers63 The Carpet America Recovery Effort (CARE) is an 

organization formed to promote diversion of carpet scrap from landfills to beneficial uses. 

The CARE 2007 Annual Report provides an overview of the collection and disposition of 

carpet scrap.64 In 2007, approximately 2.4 million pounds (1,200 short tons) of carpet 

scrap were reported utilized as alternative fuel in cement kilns, representing 

approximately one percent of the total amount of material collected and diverted from 

landfill disposal. The total amount of material diverted from landfill disposal in 2007 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

42

(approximately 296 million pounds) represented approximately 5.3 percent of the 

approximately 5,590 million pounds of material generated.65 

Recycling of scrap carpet is technically challenging and energy intensive, because carpet is 

by design made to be highly durable.66 One cement sector contact reported using scrap 

carpet as an alternative fuel, and reported that the material is difficult to process.67 Scrap 

carpet may also be difficult to collect because the material may be generated by a large 

number of relatively small and geographically dispersed carpet installers. Therefore this 

material is not widely used in cement production. Realff (2005) estimated that 

approximately 2 million metric tons of scrap carpet are disposed of in landfills, and that 

the rate of disposal is expected to increase at 3 percent per annum over the next decade. 

Scrap carpet provides both energy and raw material value to cement kilns. The lower 

heating value (LHV) of scrap carpet residues depends on the carpet material: nylon and 

polypropylene carpet residues have LHVs of approximately 17 and 28 GJ per metric ton, 

respectively (7,300 – 12,000 BTU per pound). In addition to the calorific value, scrap 

carpet also has a high fraction of calcium carbonate which would substitute for mined 

calcium carbonate and be incorporated directly into the clinker.

68

3.3.5 Other Materials

Cement plant contacts reported several other types of AFR as being used in cement kilns. 

These include latex paint solids,69 sandblast grit, storm drain solids (generated from 

municipal storm drain cleanouts)70, and agricultural byproducts (e.g., almond shells, rice 

hulls).

71 Sufficient information is not available for these materials to develop case studies. 

4. Case Study Summations

This section provides a summary of the case studies and overarching issues related to the 

beneficial use of AFR.

4.1 Alternative Fuels

4.1.1 Cost Issues

Cost is an overarching issue in selection of alternative fuels in cement production. One 

cement plant contact summed up the cost analysis methodology for alternative fuels in a 

simple manner: “Is it cheaper than coal?” As shown in Table 9, the price of coal varies 

depending upon the region of the country, in part because of transportation costs. For 

example, as of 2006, coal prices were on the order of $32 per short ton in Texas and $85 per 

short ton in Florida. Coal costs have been changing relatively rapidly through 2008 due to 

increasing transportation fuel costs and other factors, as well as exhibiting significant 

volatility. 

Another cement plant contact indicated that the company has an overall corporate policy 

to move away from using fossil fuels to the extent possible because fossil fuels are 

increasingly costly.72 Cement plant contacts that operate wet kilns or long dry kiln 

reported that their plants pursue alternative fuels more aggressively than do more modern 

dry process preheater/precalciner. The wet kiln and long dry kiln technologies are not as 

energy efficient as more modern dry process preheater/precalciner kilns, and therefore the 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

43

older technology kilns have more of a need to offset fuel costs to remain competitive with 

newer plants.73 Alternative fuels suppliers 74 concurred that the operating costs for wet 

process and long dry kilns make use of alternative fuels more of a necessity.

Table 11. Cost of Coal in Select States (per short ton)

State Price

Alabama $68.27

California $57.63

Florida $84.16

Illinois $36.95

Kansas $48.04

Missouri $45.72

New York $74.79

Texas $32.65

Source: DOE, Energy Information Administration

Note: The price of coal changes continually; these prices 

represent the cost of coal in 2006

There are various aspects to the overall cost of alternative fuels, including the capital costs 

and operating costs of: 

 Kiln and equipment upgrades;

 Performance testing; 

 Alternative Fuel conditioning (preprocessing);

 Engineered fuel production;

 Material transportation; 

 Continuous Emissions Monitoring Systems (CEMS);

Sampling and testing materials; and

 Material acquisition.

Kiln and Equipment Upgrades

Cement plant contacts indicated different approaches to management of cost for use of 

alternative fuels. Some companies 75 have company-wide initiatives to invest in upgrades 

to kilns or to materials handling equipment to initiate use of alternative fuels, and the 

company also promotes pilot projects in which different company cement plants conduct 

studies of different alternative fuels (e.g., biosolids would be tested at one company plant, 

plastics would be tested at another company plant, and the test results would inform 

ongoing corporate initiatives). In other cement companies 76 each company cement plant 

operates in a more autonomous manner, with each company cement plant conducting its 

own initiatives and managing its own costs. In some cases these companies are less 

inclined to invest in kiln or equipment upgrades and are more inclined to only test 

different alternative fuels that can be handled using existing materials handling 

equipment and existing kiln configurations. Several cement plant contacts 77 reported 

that their plants recently spent several million dollars in cement kiln or equipment 

upgrades in order to accept alternative fuel. One cement plant 78 spent several million 

dollars to configure the kiln to accept whole tires after the cement plant’s supply of 

chipped tires was interrupted; another plant 79 spent a similar amount to install material 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

44

handling and air emission (dust) control equipment to enable use of wood (sawdust) as an 

alternative fuel.

Performance Testing

In addition to the cost of making modifications to the kiln or materials handling system, 

the cost of performance testing is another cost that must be incurred to establish use of 

alternative fuels in cement production. Performance testing is generally required by state 

air quality regulations, and performance tests are designed to determine that the cement 

kiln operation is in compliance with its air emissions permit conditions. One alternative 

fuels supplier80 reported that conducting performance testing for a non-hazardous 

alternative fuel (e.g., biosolids) could cost on the order of $50,000 per kiln, and that for 

multi-kiln cement plants each kiln using the alternative fuel must be tested individually. 

Performance testing costs for an alternative fuel that is regulated as a hazardous waste

(e.g., CSOS) could be on the order of $250,000 to $500,000 81 depending upon the 

regulatory requirements in the jurisdiction where the cement plant is located. 

Cement sector contacts and alternative fuels suppliers have identified performance testing 

and associated permitting costs as a cost barrier to increased use of alternative fuels. In 

general, according to state regulatory agency contacts, each alternative fuel introduced 

into the plant is subject to individual performance test and permitting requirements. 

However, if various alternative fuel materials are preprocessed into an “engineered fuel” 

that meets defined specifications for calorific value and other fuel quality parameters, the 

cement kiln (at least theoretically) should be subject to only one performance test for the 

engineered fuel, because the quality of the engineered fuel would not vary regardless of 

the alternative fuel materials it is made from. One alternative fuel supplier 82 reported 

that they had some difficulty convincing a state regulatory agency that the quality of the 

engineered fuel was a constant, even though the alternative fuel materials it is made from 

could vary. Both cement companies and alternative fuel suppliers are advocating a 

permitting system in which the specific air emissions from the cement kiln are permitted, 

but the permit does not explicitly identify specific alternative fuels that can and cannot be 

used. Therefore, a cement plant could use different alternative fuels based on available 

supply and other factors, without having to modify the permit each time a change is made, 

provided that the air emissions limits in the permit are not exceeded. This is referred to as 

a “flexible fuel concept” of permitting.

Continuous Emissions Monitoring Systems (CEMS)

Continuous Emissions Monitoring Systems (CEMS) continuously measures air emissions 

from the cement kiln stack. A CEMS may be required by state air emissions regulations or 

by air emissions permit conditions for the cement kiln, however, not all cement plants are 

required by regulation or by permit conditions to install and operate CEMS. A cement 

plant that does not have a CEMS and that is applying for the first time to use alternative 

fuels may be required to install a CEMS as a condition of the revised air emissions permit 

for the cement plant. This represents an added capital and operating cost for use of 

alternative fuels at cement plants that do not already have a CEMS installed. 

AFR Conditioning (preprocessing) and Engineered Fuel Production
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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Certain AFRs (e.g., scrap carpet) may be required to be preprocessed for the purposes of 

size reduction, removal of undesirable constituents (e.g., for scrap carpet, nails and other 

metal components need to be removed). Preprocessing of alternative fuel materials prior 

to use in cement production represents an added cost over that for use of conventional 

fuels. Preparation of “engineered fuel” (i.e., preprocessed alternative fuel materials of a 

consistent quality from a variety of alternative fuel materials) also represents an added 

cost; however, preparation of engineered fuel has an advantage in promoting stability of 

kiln operation. 

Material Transportation Cost

Material transportation cost is also an important factor in utilization of alternative fuels. 

The cost of transporting the material itself can render the alternative fuel to be not cost 

effective. One alternative fuels supplier 83 reported that their processing plant could 

supply cement plants located up to several hundred miles from their plant, but that 

supplying cement plants located 400 miles from their plant was not cost effective. The 

effect of materials transportation costs depends in part on the value of the material being 

transported, and also in part on local landfill disposal costs. One cement plant contact 84

reported that the alternative fuels sourcing initiative is targeting alternative fuel material 

generators within a 50 mile radius of the cement plant site. Note that regulated 

hazardous wastes (including waste solvents) may be transported hundreds or thousands of 

miles from the location of the generator to a cement kiln or other facility. One refinery 

operator, for example, reported that their U.S. refineries have exported CSOS to Canada 

for treatment and disposal. 

Material Acquisition Cost

Another important issue is material acquisition cost; is the material a “waste” that the 

cement kilns charge the supplier a fee to accept, or is the material a “raw material” or 

“fuel” that the cement kiln pays the supplier to provide. CSOS, specifically, is currently 

regulated as a hazardous waste and the cement plants have generally charged the 

petroleum refineries a fee to accept CSOS for “hazardous waste treatment and disposal,”

and petroleum refiners have historically paid cement plants to accept the material for 

disposal. According to refinery contacts, CSOS was initially proposed for consideration as 

a hazardous waste because the material was being landfilled. Petroleum refiners are now 

promoting CSOS as an alternative fuel and raw material with a calorific value and also 

high silica and alumina (i.e., cement kiln raw material) content that cement plants should 

purchase from the petroleum refineries in the same manner as cement plants purchase 

other fuels and raw materials of similar value; however, the material remains regulated as 

a hazardous waste under existing regulations. Disposition of this issue may depend in 

part on the specific language of any decision to change the regulatory characterization of 

CSOS to remove the designation of the material as a hazardous waste. 

4.1.2 Technical Issues

There are various technical issues related to use of alternative fuels, including materials 

processing and handling and control of air emissions. Differences in kiln technology and 

configuration and materials handling systems mean that not every cement kiln can use 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

46

every type of alternative fuel. Materials handling systems designed for one alternative fuel 

may not be easily convertible to another type of alternative fuel. Examples of technical 

issues identified in the study include the following:

Scrap Tires and Kiln Design

Some cement kiln designs are not conducive to using whole scrap tires, and may be 

limited to use of chipped tires. This is specific to the individual cement kiln design. One 

cement plant contact, using a preheater/precalciner-type kiln, reported that the plant 85

conducted performance testing to introduce whole tires into the kiln. The testing showed 

that introduction of whole tires into the kiln riser resulted in the tire belts not moving 

into the kiln; and that introduction of whole tires lower down in the kiln resulted in 

insufficient oxygen for tire combustion. Despite spending several hundred thousand 

dollars in conducting the performance tests, the plant was unable to solve the technical 

issues. Chipping tires prior to introduction was not deemed to be a cost effective solution. 

The plant is now investigating sources of industrial rubber scrap, but is not planning on 

retesting whole scrap tires. 

Introduction of scrap tires into cement kilns can reduce cement kiln NOx emissions. One 

cement plant contact 86 reported that use of scrap tires in the cement kiln is actually 

incorporated as permit condition of the facility air permit for this reason. However, state 

regulatory agencies could not mandate the use of scrap tires in all cement kilns as air 

emissions control strategy, because some kilns cannot accept scrap tires. 

Materials Handling Systems

Several cement plant contacts indicated that one technical issue with respect to materials 

handling is that their plant’s materials handling system cannot handle two types of 

materials simultaneously (this is an issue both for alternative fuels and alternative raw 

materials). Therefore for these plants a decision to apply the materials handling system to 

a specific alternative fuel (e.g., wood) is effectively a decision to forego use of a different 

alternative fuel (e.g., plastics). Materials handling systems can be designed to 

accommodate multiple types of materials, however there is an increased capital cost 

involved in such flexible design. Also, different materials can be preprocessed to similar 

characteristics (e.g., size reduced) such that a single materials handling system can handle 

the different materials, however preprocessing the materials also involves a higher 

operating cost than using the materials as generated.

Also, C&D debris must be pre-sorted, processed, and pre-sized to be used in cement kilns. 

One cement plant contact with experience with wood generated from C&D debris 87

reported that one issue encountered was the difficulty in separating the gypsum wallboard 

and other non-combustible materials in the C&D debris from the wood. Only one cement 

plant contacted 88 reported that the plant is currently using wood generated from a C&D 

debris yard.

Preprocessing of Refinery Spent Catalyst and Other Materials
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

47

Refineries generate a variety of materials (spent sandblasting media, granular catalyst 

beads, support balls, catalyst fines filter cake) that can be commingled to achieve a 

mixture that can be easily managed by conveyor belt systems. In addition, commingling 

enables blending of the chemical properties so that the material becomes more uniform 

chemically and physically. Stockpiling materials over several months promotes uniformity 

and large enough quantity to facilitate the variety of catalysts and other materials

generated by the refinery. 

4.1.3 Regulatory Issues

Cement plant contacts, regulatory agency contacts, and materials supplier contacts 

identified specific regulatory issues related to alternative fuels included in this study. 

In general, cement kilns operate under a set of permit conditions established by the 

plant’s Clean Air Act Title V Operating Permit. The permit conditions limit the emissions 

of criteria air pollutants (e.g., nitrogen oxides (NOx), carbon monoxide (CO), sulfur 

dioxide (SO2), and particulate matter (PM)) and hazardous air pollutants. Cement plants 

that do not burn hazardous waste are subject to MACT Standard 40 CFR 63 Subpart LLL, 

which regulates emissions of chlorinated dioxins/furans, particulate matter, mercury, and 

total hydrocarbons. A separate MACT Standard for hazardous waste combustors (HWCs) 

applies to cement kilns that burn hazardous waste. In general, cement kilns operate 

under Title V Operating Permits issued by state regulatory agencies implementing Clean 

Air Act programs.

Cement plants using alternative fuels may also need to obtain other state permits, 

including solid waste facility permits, depending upon the specific state regulations and 

the type of alternative fuel being used. Cement kilns using biosolids or scrap tires, for 

example, may be subject to state regulatory requirements to obtain a “solid waste facility” 

operating permit. Other states, e.g., South Carolina, exempt “recycling” facilities 

(including facilities burning alternative fuels for energy recovery) from state solid waste 

facility permit requirements. 

Cement plant contacts and regulatory agency contacts provided information concerning 

how the environmental permitting process is implemented for cement plants testing the 

use of new alternative fuels. In general, cement plants are required to obtain construction 

permits to establish the use of a new alternative fuel, in part because modifications to the 

materials handling system involving capital expenditure need to be permitted.

89 Shortterm testing of new alternative fuels for which no capital expenditure is required may be 

conducted under the MACT Standard without a permit modification. In this case there 

would be a limit on the duration of the test and the amount of alternative fuel material 

that could be tested. Cement kilns are generally required to conduct air emissions 

performance testing to demonstrate that use of the alternative fuel would not result in an 

increase in the air emissions from the cement plant. Cement kilns that have CEMS can 

use these systems to monitor emissions during performance tests; cement kilns that do 

not have CEMS would need to conduct physical testing of their emissions. If an increase 

in air emissions would result then other regulatory standards would be triggered. It is not 

necessarily the case, however, that every new use of alternative fuel or every modification 

needs to be permitted. State agencies 90 have developed guidance documents that outline 

what proposed activities would require permits. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

48

Cement kilns conducting tests of new alternative fuels are generally granted a short-term 

permit by the regulatory agency to conduct performance testing both to test the technical 

performance and feasibility of using the alternative fuel. Several regulatory agencies 91 

reported that cement plants applied for and were granted permits to test alternative fuels 

[and also raw materials] that ended up not being used because of technical difficulties (as 

opposed to issues concerning the cement plant air emissions). 

Scrap tires, CSOS, ASR, and biosolids each have unique regulatory issues with respect to 

permitting, performance testing, and public perception when used as alternative fuels. 

Scrap paper/wood and plastics are generally regulated as non-hazardous (municipal solid)

wastes and have fewer specific regulatory issues; however, permit modifications and 

performance testing are generally required for cement plants to initiate use of these 

materials as alternate fuels. In general, construction or modification of materials handling 

systems or air emission control systems or kiln modifications made to accommodate nonhazardous waste alternative fuels would necessitate permit revisions. 

Performance testing and permitting requirements for hazardous waste alternative fuels 

(e.g., CSOS) would be significantly more expensive and time-consuming than for nonhazardous waste alternative fuels, because hazardous waste combustion is subject to the 

Hazardous Waste Combustor MACT Standards and other standards that specify the 

permit and performance testing requirements. These requirements would generally 

include preparation of a risk assessment in addition to performance testing.

CSOS

CSOS is a listed hazardous waste (RCRA Waste Code K170) and therefore only cement 

kilns that are permitted to accept hazardous waste can accept this material for use as an 

alternative fuel (only 18 cement plants have hazardous waste combustor permits).

Therefore the utilization of this material is constrained first by the logistics and 

geographic relationship of the CSOS generators (petroleum refineries) and the permitted 

cement kilns, and second by the need to handle the material as a hazardous waste, 

including transportation of the material by licensed waste transporters. As a result, most

petroleum refiners92 contacted for this study reported that they are inclined to manage the 

CSOS that they generate onsite rather than send the material off site (either to a cement 

kiln or other offsite treatment or energy recovery) as a hazardous waste. In other cases 93

there are no cement kilns in the vicinity of the petroleum refinery that are permitted to 

accept the CSOS, therefore the material is sent to other offsite facilities for treatment and 

disposal. 

The TXI cement kiln in Midlothian TX, the Ash Grove cement kilns in Foreman AR and 

Chanute KS, the Lafarge (Systech) cement kiln in Fredonia KS, the Continental Cement 

kiln in Hannibal MO, and Giant Resource Recovery in Harleyville SC are all permitted to 

accept K170 hazardous waste. However, according to EPA hazardous waste reporting 

system data, these facilities’ acceptance of CSOS from refineries has been intermittent. 

Petroleum refiners have been pursuing an initiative through their trade association (the 

American Petroleum Institute) to change the regulatory characterization of CSOS so that 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

49

the material is not regulated as a hazardous waste (or as a solid waste) but rather as a fuel 

material (i.e., as a refinery product) when legitimately used as a fuel, such as in a cement 

kiln. The refineries suggested that the most direct approach to defining CSOS as a nonhazardous waste is through the EPA “definition of solid waste” (DSW) regulatory process. 

If CSOS is deemed by EPA not to be a “solid waste” when beneficially used, then the 

material inherently cannot be classified as a hazardous waste either. This change in the 

characterization of the material could facilitate utilization of the material in commerce. 

Currently much of the CSOS generated is managed on site at the refineries. According to 

refinery contacts 94 if the CSOS were to be reclassified as a non-hazardous waste, or 

reclassified as a non-solid waste, it could be sold as a refinery product into higher value 

offsite markets. Also, if the material were not regulated as a hazardous waste, 

theoretically any cement kiln could accept it. The combination of the increase in the 

amount of the material available in commerce and the number of cement kilns that could 

accept the material could result in increased utilization of the material in cement kilns as 

an alternative fuel. Reclassifying the material as a refinery product may enable petroleum 

refineries to sell the material to cement kilns (as a product) rather than having to pay the 

cement kilns to accept the material. So it is also possible that cement kilns would not 

accept CSOS if the cement companies had to pay for it. One refinery contact reported 

that the refinery has already established a contact with cement plants that are paying for 

the CSOS. The emergence of CSOS as an AFR that was not classified as waste or 

hazardous material would open a new market comprised of all the cement companies 

unable to use the material now. The utility of the material and its price would be 

negotiated, but could ultimately be more than it is now.

Petroleum refiners could also more easily consolidate batches of CSOS from their own 

refineries, or a consortium of refineries, into large shipments of material to a cement kiln 

if the material was to be regulated as a product rather than as a waste. As it is now, such 

consolidation would also have to be conducted at a facility permitted to accept hazardous 

waste.

TCEQ expressed interest in reclassifying CSOS, but a decision from the EPA Office of Solid 

Waste (OSW) is needed on this issue for TCEQ to make a decision.95 Correspondence 

between the API and EPA OSW on this issue has been underway for several years without 

any decision being made by EPA OSW on the regulatory characterization of the material.

Scrap Tires

Regulations related to management of scrap tires vary by state and within states. The 

RMA has reported that several states have achieved a program in which most or all scrap 

tires generated in the state reach end use markets. 96 Other states have not achieved such 

performance.97 For example, the State of South Carolina has ongoing issues with scrap tire 

piles, and although three cement kilns in South Carolina are permitted to use scrap tires, 

only two of the three are currently doing so.98 99 Several state regulatory agency contacts 

reported that regulations concerning whether scrap tires can be landfilled, and if so in 

what physical form, are established by the local government agencies operating MSW

landfills. Certain states 100 categorize scrap tires as “solid waste” and regulate the 

combustion of scrap tires under the state solid waste management regulations. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

50

One regulatory agency contact 101 reported that an air emissions (concentration) limit for 

sulfur dioxide (SO2) applies to the combustion of scrap tires and that some cement kilns in 

the state were not able to meet the limit, limiting their ability to use scrap tires. 

Biosolids

Biosolids (municipal wastewater treatment sludge) from wastewater treatment facilities 

can be legally used or disposed in three ways: (1) application of treated and tested 

biosolids to soils; (2) landfilling; or (3) incineration or combustion for energy recovery. 

The Clean Water Act provides the legal basis for management of biosolids nationwide. 

EPA established minimum national standards protecting human health and the 

environment at 40 CFR Part 503. Beyond these national standards, state and local 

governments make the key decisions regarding biosolids management.

One regulatory issue related to utilization of biosolids in cement kilns is the regulatory 

classification of the material with respect to pathogen content. Biosolids, as generated at 

POTWs, contain pathogens, and biosolids applied to different alternative uses (e.g., 

energy recovery, land application) have different regulatory classifications. 

 

An alternative fuels supplier 102 that conducted performance tests of a cement kiln 103 using 

biosolids in California reported that the test was required to be conducted using only 

“Class A” biosolids. [This is not unreasonable considering that the cement kiln could 

otherwise potentially introduce pathogens into the cement plant materials handling system

if “Class B” biosolids were used.] However, Class A biosolids must be subjected to 

temperatures of 60° C, which requires energy, while Class B biosolids, which can be 

applied to soil, are not required to be subjected to heat. Therefore there is an “energy 

penalty” associated with preparation of biosolids for use as alternative fuel in cement kilns 

that would not be incurred if the material was land disposed. 

Another regulatory issue concerning biosolids is recent state and local government 

legislation to reduce emissions of greenhouse gases, and particularly CO2 emissions. 

Biosolids are biogenic materials that are “CO2 neutral.” Use of biosolids in cement 

production to replace fossil fuels can therefore reduce the total CO2 emissions per ton of 

cement produced. 

Automobile Shredder Residue

The PCA E&E subcommittee contact 104 indicated that TSCA regulations specifically 

categorize ASR as a “PCB Waste” unless proven otherwise, and that it is “difficult to prove 

otherwise.” EPA regulation 40 CFR §761.62(b)(1) Disposal of PCB bulk product waste 105 106

applies specifically to landfilling of ASR but also, according to cement sector contacts, is 

being applied by EPA Region VI to incineration of ASR. Section (b)(i) specifically applies 

to landfilling of ASR. As of 2005, EPA Region VI was strictly interpreting the phrase "from 

which PCB small capacitors have been removed" in the regulation as applying to ASR, and 

interpreting the phrase in ways that shredders could not certify compliance. A recent 

study by the California DTSC on beneficial use of ASR as alternative fuel in cement kilns 

concluded that the current regulatory framework for ASR with respect to PCBs actually 

promotes landfilling of the material as opposed to beneficial uses and that changes to the 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

51

regulatory framework applicable to ASR may be needed to facilitate use of ASR as an 

alternative fuel in cement kilns.

107

4.1.4 Supply/Logistics Issues

Obtaining a sufficient long-term supply of material of consistent quality is a principal 

issue concerning use of alternative fuels in cement kilns. A principal reason for this is that 

a cement plant may need to spend several million dollars to purchase or upgrade the kiln 

or materials handling equipment in order to establish use of an alternative fuel, and an

assurance that a long-term supply of material will be available would be needed to justify 

such expenditure. Materials handling systems that are designed for a specific alternative 

fuel (e.g., biosolids, plastics, wood) may not be easily converted to handling a different 

alternative fuel if supply of the original alternative fuel is interrupted, and even if so, the 

cement plant would incur costs in converting the materials handling system for the new 

material. Another reason why cement plants need a sufficient long-term supply of 

material is to maintain stable kiln operation. Unanticipated changes in the characteristics 

of the raw materials and fuels to the cement kiln that need to be made due to interruption 

of supply can result in kiln upsets.

Several companies operate wholly-owned subsidiaries that are responsible for sourcing of 

AFR. The subsidiaries obtain materials from suppliers, process the materials, and 

transport the materials to the company’s cement plants.108 Other cement companies 

contract with third party contractors 109 that perform the same functions as the cement 

company subsidiaries do. 110 Third-party contractors may provide services to more than 

one cement company; the subsidiaries are captive to a particular cement company. Other 

cement plant contacts indicated that their plants are relatively autonomous with respect 

to sourcing of AFR.

111 Some cement companies are working with independent suppliers of 

“engineered fuel” that is manufactured to a specific quality specification for the cement 

kiln. The independent supplier is responsible for sourcing alternative fuel materials that 

are used as raw materials in making the engineered fuel, manufacturing the fuel to quality 

specifications, and delivering the fuel to the cement plant. 

Subsidiaries and private sector companies have been effective in materials sourcing of 

alternative fuels for cement plants. For example, one cement plant 112 recently established 

use of plastics, cardboard, scrap paper, and rubber scrap an alternative fuels. The plant 

installed two on-site shredders and other materials handling equipment that cost on the 

order of $7 million. The cement plant subsidiary company responsible for material 

sourcing established individual contracts with between 10 and 20 suppliers of these 

materials to obtain a sufficient supply of alternative fuel material for the cement plant. 

These suppliers are industrial facilities, not recyclers of post-consumer MSW.

The availability of material for use as alternative fuel may also be related to the relative 

price to dispose of the material in a landfill and/or the relative cost of alternative 

beneficial uses. Cement plant contacts 113 and alternative fuels suppliers 114 reported that 

the available supply of plastics may be constrained because MSW recycling agencies may 

be more inclined to send post-consumer recycled plastic to plastics manufacturers to be 

used as raw materials, rather than to cement kilns or other facilities for energy recovery. 

“Unrecyclable” plastics may also be unavailable as a cement plant alternative fuel if the 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

52

cost of landfilling the material is sufficiently low, unless cement companies are willing to 

pay fair market prices for those materials based on their inherent calorific value. 

Finally, cement kiln use of alternative fuels and raw materials that would otherwise be 

disposed as waste plays a part in EPA’s hierarchy of waste management. EPA emphasizes 

reducing waste generation whenever possible. If byproduct material is generated, EPA 

encourages minimizing the quantity released or disposed as waste by recycling or reusing

it, using it to produce energy, or treating it.

4.1.5 Trends Analysis

The overall trend is towards increasing use of alternative fuels, with emerging materials 

representing a potentially increasing percentage of the total amount of alternative fuels 

used. Generally cement plant contacts reported that the utilization rate of the alternative 

fuels used has been relatively constant from year to year. According to data in the 2006 

PCA Labor and Energy Report, overall use of alternative fuels in U.S. cement plants has 

been relatively constant at 9 percent of total energy input for the past several years. 

Cement plants contacted indicated the amount of energy derived from alternative fuels is 

as low as zero percent for some cement plants 115 and as high as 50 percent for others. 116 

Specific trends for alternative fuels evaluated in this study are described below.117

Scrap Paper/Wood and C&D Debris

As discussed above, only one cement plant contact 118 reported that their plants are using 

alternative fuels (wood) derived from C&D debris. No other cement plant contacts 

reported that their plants either using or investigating use of wood derived from C&D 

debris. Several cement plant contacts 119 reported that their plants recently established use 

of scrap paper/wood (e.g., scrap paper and cardboard) and that utilization rates are 

relatively constant. However, several other contacts at cement plants that are using scrap 

paper/wood reported that they are considering phasing out the use of scrap paper/wood 

in favor of other alternative fuels (e.g., plastics).

120 More recently, several states have 

banned disposal of C&D debris in landfills or are contemplating doing so, including 

Massachusetts and New York, creating an additional supply of C&D debris that could 

potentially be processed into alternative fuel for cement kilns.

CSOS

Cement plant 121 and petroleum refinery contacts 122 did not provide detailed information 

concerning the amount of CSOS being used as an alternative fuel in cement kilns; data 

from the EPA hazardous waste reporting system on the disposition of K170 waste indicates 

that use in cement kilns has been intermittent. Petroleum refinery contacts reported that 

they are pursuing market initiatives and identifying cement kilns that are permitted to 

accept CSOS in an effort to increase the amount of CSOS used in cement kilns. The 

availability of CSOS for utilization as alternative fuel in cement kilns would likely increase 

if regulatory barriers restricting the use of this material to RCRA-permitted cement kilns 

are addressed, as more CSOS would be readily available and more cement kilns would be 

able to accept it. One can anticipate changes in the market valuation of the CSOS if the 

material were not classified as a hazardous waste, and this may affect the pattern of future 

utilization of this material in cement kilns and other facilities for energy recovery. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

53

Scrap Tires

Cement plant contacts at plants that are already using scrap tires generally reported that 

they are either using the maximum amount of scrap tires that the cement kiln is physically 

capable of processing (or that the cement kiln is permitted to process) or that they are 

conducting performance tests or initiating kiln modifications to increase the number of 

scrap tires that they can process. Several cement plant contacts reported that their plant 

is actually permitted to process more scrap tires than can physically be fed to the kiln.123

One cement plant contact 124 reported that the supply of scrap tires available in the area of 

one of their plants exceeds the capacity of the cement kiln to use them; surplus scrap tire 

supply is chipped and transported to a second of the company’s cement kilns for use as an 

alternative fuel.

Contacts at cement plants that are not currently using scrap tires generally did not report 

they are pursuing permits to use scrap tires at their plants. As discussed above, overall 

utilization of scrap tires as alterative fuels in cement kilns has been increasing. An issue 

that may tend to reduce the utilization of scrap tires in the future is the fact that certain 

types of cement kilns (e.g., short dry process kilns) cannot as easily process whole tires as 

other types (e.g., long wet process kilns).. Ongoing conversion of wet process plants to 

dry process plants may reduce the number of kilns for which accepting whole tires is 

feasible. 

Biosolids

No specific trends data are available for biosolids, however, it appears from the number of 

cement plant and alternative fuels supplier contacts that provided detailed information 

concerning biosolids that utilization of this material in cement kilns is likely to increase 

substantially in the near future. Several cement plant contacts reported using biosolids as 

an alternative fuel and other cement plant contacts reported that they are investigating 

the use of this material either as a replacement for other alternative fuels (e.g., wood125) or 

as a new alternative fuel.126 Other cement plants were identified that have recently 

conducted performance tests using biosolids.127 Private sector companies that produce 

alternative fuels for cement kilns 128 are drying and processing biosolids materials 

specifically for cement plants.

129 One company is operating sludge dryers in New Jersey to 

supply a cement kiln in Indiana and in Baltimore City to supply a cement kiln in 

Maryland; a second company is producing alternative fuel to supply cement kilns in 

Western Pennsylvania; this company reported that the alternative fuel they produce has 

up to 40 percent biogenic content.

Plastics 

Several cement plant contacts reported that they have recently conducted performance 

tests using plastics or have recently established the use of plastics130 and that their plastics 

utilization rates are relatively constant. One cement plant recently established the use of 

plastics through materials sourcing conducted through a wholly-owned subsidiary.131

Plastics are an emerging material; increased utilization of plastics will depend upon 

addressing supply/logistics barriers. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

54

Automobile Shredder Residue

Only one cement plant was identified that is currently evaluating ASR as an alternative 

fuel. ASR is an emerging material; establishing utilization of this material in cement kilns 

will depend on addressing regulatory barriers.

Hazardous Waste Fuels

One cement plant contact 132 that has several cement kilns permitted as hazardous waste 

combustors reported seeing a slow but steady decline in the available supply of hazardous 

waste for use as alternative fuel over the past several years. This is in part because there is 

competition from other energy recovery facilities for hazardous waste fuel and in part 

because industrial facilities are continuing their waste minimization/pollution prevention 

efforts and thereby they are generating less hazardous waste. Another reason is very likely 

that the kilns are charging the generators to accept it rather than paying for it based on its 

fuel value, which drives generators to look for other alternatives.

4.1.6 Emerging Materials

One cement plant contact 133 reported using scrap carpet generated from residential and 

commercial building carpet installers as an alternative fuel. Two cement plant contacts

134

reported using oil filter fluff as an alternative fuel. Oil filter fluff is generated from used 

vehicle motor oil filters after the free oil and the metal parts are removed. The remaining 

oil-soaked paper is used as an alternative fuel. 

4.2 Summary – Alternative Fuels

4.2.1 Scrap Paper/Wood and C&D Debris

Construction and demolition debris was deleted from further consideration in this report 

because only one cement plant contacted was found to be directly using wood derived 

from C&D debris. No other cement plants were identified that were either using or 

investigating using alternative fuels derived from this material. 

The principal issues associated with the utilization of alternative fuels derived from C&D 

debris in cement production are the feasibility of processing this material into a consistent 

physical condition such that the material can be conveyed into the kiln, and the 

availability of a consistent supply of this material for the cement kiln. As discussed above, 

C&D debris (including wood) generated from Hurricanes Katrina/Rita was offered to one 

cement plant 135 but found to be unsuitable for processing into alternative fuel because 

the wood was commingled with other C&D debris. Cement plant contacts reported 

utilization of scrap paper/wood, including recycled cardboard, landscaping wood, and 

sawdust from lumber mills, and provided information concerning the supply and quality 

issues associated with the use of scrap paper/wood.

A contrast can be drawn to the case study for a cement kiln using wood (sawdust) 

generated by a lumber mill.136 The sawdust is generated in a dry condition and in a form 

that can be conveyed pneumatically into the cement kiln. The permitted feed rate is 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

55

approximately 5 short tons per hour. The cement plant incurred a significant amount of 

capital expenditure to install conveying equipment and emission control designed to 

prevent the material from becoming wet and also to prevent fugitive dust emissions; if the 

material becomes wet it could create blockage in the conveying equipment. If the 

material becomes wet, the moisture content also reduces the calorific value of the 

material, making it less desirable as an alternative fuel. The cement plant also invested 

significant amount of capital for performance testing and obtaining permits to use the 

material.

A contrast can also be drawn to the case study for a cement kiln using wood generated by 

a regional landscaping company.

137

 This material is primarily creosote-treated wood used 

in landscape architecture. The material is processed into shredded wood by a supplier. 

Based on an average calorific value of 6,500 BTU per pound for wood and 12,000 BTU per 

pound for coal, two tons of wood are needed to replace one tone of coal. The cement 

plant reported an annual utilization rate of approximately 10,000 short tons per year wood 

waste (an hourly feed rate of four tons per hour). The cement plant contact reported that 

the plant was considering phasing out the use of this material because of uncertainty of 

the long-term supply of the material. This plant also invested a substantial amount of 

capital in purchasing materials handling and conveying equipment and also on the 

performance testing process, which took approximately two years to complete. The plant 

is considering converting the materials handling system to handle plastics instead of 

wood. 

C&D debris would necessarily be generated on an intermittent basis under normal 

circumstances. Even in the event that a large amount of C&D debris was generated (e.g., 

from a tropical storm event) the material would need to be organized (likely from multiple 

points of generation) and then processed into a consistent long-term supply of consistent 

quality to be used as alternative fuel in cement kilns. Cement kilns would need to already 

have materials handling equipment in place to handle the processed material. Processing 

generally non-homogenous, and also potentially wet, C&D debris into a conveyable 

physical condition compatible with the materials handling equipment would be more 

difficult and costly than processing a relatively homogenous material generated by a 

lumber mill or by a landscape supplier. The capital investment needed for the materials 

handling equipment and the performance testing required to obtain a permit to burn the 

material are significant, and therefore cement plants would want some assurance of a 

consistent and long-term supply of a material of known quality to recover this investment. 

Cement plants also may not be able to obtain a permit to burn a certain type of alternative 

fuel material from a certain source and then change to another type of alternative fuel 

material from another source. 

4.2.2 Refinery Spent Catalyst and Clarified Slurry Oil Sediments

The CSOS generated by petroleum refineries is managed in several ways. Petroleum 

refineries can return this material to the onsite refinery coking unit or other refinery 

processes, send the material to other petroleum refineries for processing, send the 

material to a RCRA hazardous waste-permitted cement kiln or other hazardous waste 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

56

facility for use as an alternate fuel, or (in limited cases) send the material to Canada for 

treatment and disposal. h

As discussed in Section 4.1.3, petroleum refineries, through their trade association, the

API, are pursuing a reclassification of CSOS so that the material would be regulated as a 

refinery product when beneficially used as a fuel or raw material in cement 

manufacturing, rather than as a hazardous waste or as a solid waste. A decision by EPA

OSW would be needed to reclassify CSOS as a refinery product. 

Gulf Coast petroleum refineries are already sending CSOS to hazardous waste-permitted 

cement kilns in the Gulf Coast Region. One refinery 138 reported that one of their refineries 

is sending some CSOS to a cement kiln139 but that the company’s other refineries are 

generally managing this material on site even though it may be less expensive to send the 

material offsite to a RCRA-permitted hazardous waste facility. 

Petroleum refinery contacts reported that that one reason why CSOS is being managed 

onsite at potentially higher cost is to reduce the amount of hazardous waste generation 

reported by the refineries. The amount of hazardous waste generated by each refinery 

annually and sent offsite for disposal is publicly reported through the RCRA Biennial 

Hazardous Waste Report, and certain constituents may be reportable through the Toxic 

Release Inventory when shipped offsite as a waste. Refinery contacts indicated that the 

public perception associated with the required classification of this material as hazardous 

waste when shipped offsite, even for beneficial use as a fuel or raw material to cement, is 

an important factor in their decision to manage CSOS on site (at greater expense).

Refinery contacts indicated that they are conducting research into changing the method 

by which they maintain their CSO tanks in order to generate a lower quantity of CSOS. 

The CSO product is generally generated with roughly 1 percent or less solids; the 

remainder of the solid in the CSO tanks settles and is eventually removed as CSOS (a 

mixture of CSO and catalyst fines/solids). The refineries are researching methods of 

shipping the CSO with higher solids content to cement kilns. One refinery contact 140

reported that they had shipped CSO with a solids content of up to 20 percent in 

specialized transport trucks. Solids are generally classified as CSOS after they settle out of

the CSO in the CSO storage tanks (although interpretation of this definition is one of the 

issues under discussion between the API and EPA OSW). Any solids that remain 

contained in the CSO product prior to settling are not classified as CSOS. 

Refinery contacts also indicated that they are conducting research into consolidating the 

CSOS generated from several refineries (either their own company’s refineries or others) 

and blending the material into a consistent supply for cement kilns. Consolidation is 

useful for refineries and cement kilns because individual refineries generate CSOS only on 

a batch basis (but potentially in million pound quantities) when maintaining their CSO 

storage tanks. CSO tank maintenance schedules among refineries in the same region 

 

h

Treatment and disposal of CSOS in Canada would not be feasible for a Gulf Coast petroleum 

refinery, and anticipated changes to Canadian waste management regulations in the future may 

preclude this option for managing CSOS.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

57

could potentially be coordinated to levelize the amount of material generated if there was 

a reliable market outlet driver to do so. 

Presently, however, the RCRA hazardous waste designation of this material represents a 

significant cost barrier to improved management of the CSOS. Petroleum refinery 

contacts indicated that it is difficult to ship CSOS to cement kilns in hazardous waste 

transport trucks on a daily basis, both because of the cost and because of the logistics of 

scheduling hazards waste shipments.141 Both the cost and the logistics barriers would be 

addressed if the CSOS were reclassified as a refinery product; transport could be 

conducted in conventional trucks complying with standard DOT requirements for similar 

hazardous materials rather than by licensed hazardous waste transporters, and at lower 

cost. At the same time, reclassification of the CSOS would increase the number of cement 

kilns that could potentially accept this material as an alternative fuel. The issue of 

whether cement kilns would continue to charge refineries for the material or whether 

refineries would be able to sell the material to cement kilns (as a refinery product) would 

need to be addressed. Cement kilns would be able to evaluate the utilization of CSOS 

based on cost and technical issues rather than based on whether or not the cement kiln is 

permitted to accept hazardous waste. This could greatly expand the utilization of CSOS 

as an alternative fuel in cement kilns, particularly in regions where there are refineries but 

not a large concentration of cement kilns that are permitted to accept hazardous waste.

142

4.2.3 Scrap Tires

Cement plants made up 38 percent of the market for tire-derived fuels in 2005.143 Contacts

at several cement plants using scrap tires reported that the plants are using as many tires 

as the kilns are physically capable of accepting based on the equipment configuration, and 

others reported that their plants are either retrofitting additional existing kilns to accept 

scrap tires144 or making modifications to their kilns to enable an increased throughput of 

scrap tires.145 Some cement plant contacts146 reported that their plants are actually 

permitted to burn more tires than the kiln is actually physically capable of burning, on 

account of process limitations. Cement plant contacts reported various rates of scrap tire 

utilization, from 5 percent of the heat input (equivalent to one scrap tire per minute)147 to 

12 percent of raw mix as tire-derived fuel, corresponding to approximately 1,000 short tons 

per year of whole tires.148

Contacts for several cement plants using scrap tires reported that there is increasing 

competition for scrap tires from other beneficial uses (e.g., crumb rubber) and also from 

continued disposal of scrap tires in landfills. These conditions may be characteristic of the 

specific local markets and do not necessarily reflect the overall national upward trends of 

scrap tire utilization for both energy recovery and for crumb rubber applications.

Scrap tire management programs vary by state, and in some cases vary by local 

jurisdiction. Certain states subsidize beneficial use of scrap tires by charging a fee to 

consumers for each scrap tire collected. The fees are applied, for example, to grants for 

projects utilizing scrap tires. Other states are either prohibited by law from collecting 

such consumer fees, or are prohibited by law from spending such fees as grants to use of 

scrap tires as alternative fuel.

149 Also, State Departments of Transportation may actively 

support production of crumb rubber for use in production of rubberized asphalt. 

California, Arizona, and Florida are the largest users of crumb rubber for production of 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

58

rubberized asphalt. This application consumed approximately 12 million tires in 2006. 

Other states using increasing amounts of asphalt rubber include Texas and South 

Carolina. 150

Despite various state-level programs to promote beneficial uses of scrap tires, a significant 

number of tires are disposed of in landfills. The RMA reported that in 2005 14 percent of 

scrap tires generated were land disposed.151 152 In some states, local governments operating 

MSW landfills implement local regulations concerning landfilling of scrap tires and other 

non-hazardous solid waste. In one state,153 for example, revised regulations were recently 

implemented that allowed landfilling of cut up tires. Under the previous regulations, 

whole tires or cut up tires could not be landfilled, and therefore local suppliers chipped 

the scrap tires to supply alternative fuel to cement kilns and other applications. Upon 

implementation of the revised regulations, these suppliers no longer had any regulatory 

incentive to chip scrap tires, as scrap tires could be cut up and landfilled at much lower 

cost (chipping tires is an energy-intensive process.) As a result, one cement plant contact 

reported that the plant could no longer obtain a supply of chipped tires. The company 

had to spend several million dollars to outfit the cement kiln to accept whole tires instead 

of chipped tires in order to reestablish the use of scrap tires as an alternative fuel. 

Public perception of utilization of scrap tires in cement kilns was also found to vary 

widely. One cement plant contact reported that the plant initiated a pilot project to burn 

scrap tires and obtained broad acceptance of the program from both the regulatory agency 

and the local community. Unfortunately, the pilot program was not successful; the kiln 

dimensions were not amenable to mid-kiln introduction of the scrap tires, and the raw 

material feed was also not of sufficient dimension to feed whole tires. Chipping the tires 

was deemed to be cost-ineffective.154

Several cement plant contacts reported that the utilization of scrap tires as an alternative 

fuel in the kiln is actually categorized by state regulators as a nitrogen oxide (NOx) air 

emission control strategy, and the utilization of scrap tires is actually incorporated into 

the air emissions permit for the cement kiln.155 Use of scrap tires has been shown to 

reduce NOx emissions from cement kilns. Other states 156 have a state-wide ban on the use 

of scrap tires in cement production. 

4.2.4 Wastewater Treatment Sludge (Biosolids)

As discussed in Section 3.3.2, biosolids are generated by municipal wastewater treatment 

plants throughout the U.S., and large amount of this material is potentially available for 

use as an alternative fuel in cement kilns. Several cement plant contacts157 reported that 

the plant is using biosolids and others reported that they are investigating the use of 

biosolids 158 or have conducted performance testing for biosolids.

159

 

Cement plant contacts and regulatory contacts indicated that the public and regulatory 

perception of use of biosolids in cement kilns is lower than that for wood, and permitting 

can therefore be more difficult. Wood has in some cases been viewed as a cleaner fuel 

than coal, while the perception not necessarily the case for biosolids. This could affect the 

type performance testing and public involvement for proposed use of biosolids. As 

discussed in Section 4.1.3, there are regulations that require the biosolids to be processed 

prior to use in cement kilns, and the material has to be “dry” in order to be desirable as an 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

59

alternate fuel. Therefore there is an energy cost to processing the material. Further, as 

discussed above, in some jurisdictions biosolids can be land disposed with less intensive 

treatment than would be required for use in a cement kiln. Therefore both land disposal 

costs and treatment costs are a potential barrier to increased use of biosolids in cement 

kilns. 

Cement kilns using biosolids have been required to conduct performance testing to 

demonstrate that air emissions (e.g., NOx emissions) would not increase.160 Cement sector 

contacts reported that such performance testing was successful.

161

4.2.5 Plastics

Several cement plant contacts reported using plastics, either generated by MSW recycling 

programs or generated by industrial plants that manufacture plastic products; other

contacts indicated that their plants are investigating using plastics either by identifying 

private sector suppliers or by investigating how to partner with municipal government 

MSW recycling programs. Two important issues related to utilization of plastics as an 

alternative fuel in cement kilns are obtaining an adequate supply of the material and 

managing the quality of the material. 

Cement plant contacts and regulatory agency contacts reported that in some jurisdictions 

plastics generated from MSW recycling programs are not segregated adequately such that 

the plastics can be used as alternate fuel in cement kilns.162 Cement kilns do not want 

chlorinated plastics (e.g., polyvinyl chloride) in their feed stream because the chlorine in 

the plastic can generate air emissions (e.g., chlorinated dioxins and furans) in excess of 

permit limits. Cement kilns also closely control the chlorine content of the raw mix 

because chlorine can affect the quality of the clinker produced. However, cement plants 

in different regions with different characteristics of available raw materials may have 

different tolerances for the amount of chlorine, depending on the alkali content of the raw 

materials and other parameters.

Cement plant contacts and regulatory agency contacts also reported that the recycling 

rate for plastics in many jurisdictions is not as high as it could be, reducing the amount of 

plastics collected for potential utilization in cement kilns.

163

 Municipal governments 

responsible for operating MSW recycling programs in some cases would need to invest in 

equipment (e.g., sorters, shredders) and establish additional procedures to adequately 

segregate plastics and supply the plastics for use in cement kilns. The benefits of such 

investment would be a steady supply of high calorific value fuel (on the order of 14,000 

BTU per pound) for the cement kilns and reduction of the potential for generation of 

landfill gas from disposal of plastics in landfills. However, cement plant contacts reported 

that it is not necessarily clear to the municipal governments managing the MSW programs 

that such capital or labor cost expenditures would pay for themselves in the increased 

value of the plastics that could be supplied to cement kilns. This is particularly the case in 

regions where the cost of landfill disposal is low. Low landfill disposal costs may drive 

local government decision making concerning recycling programs. Cement plants can 

either purchase shredded plastic from a supplier or install a shredder onsite. Installation 

of a shredder on site would be a significant capital expenditure. Some plants using 

plastics have chosen to install shredders on site, while others have chosen to purchase 

shredded plastic from a supplier. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

60

One cement plant contact 164 reported that they are investigating how to form 

partnerships with municipal government recycling agencies to promote increased and 

improved segregation of plastics. In the company’s estimate the additional sorting of 

materials would ultimately “pay for itself.” Another cement plant contact 165 reported that 

their materials sourcing subsidiary recently conducted a market study to identify sources 

of plastics for the cement kiln. The subsidiary did not identify post-consumer plastics 

from MSW recycling agencies, but rather plastics generated by local industries. This is an 

indication that the MSW recycling agencies either are not generating plastics in sufficient 

quantities to supply the cement kiln or that the plastics being generated are not being 

adequately segregated.

4.2.6 Automobile Shredder Residue

Automobile shredder residue (ASR) is an emerging material. As discussed in Section 4.1.3, 

a principal barrier to use of this material in cement kilns is its regulatory classification. A 

recent study by the California DTSC assessed the regulatory and technical barriers to use 

of ASR as an alternative fuel in cement kilns. 166 In addition to the regulatory issues 

related to PCB capacitors, other potential regulatory issues include the occurrence of 

mercury switches and lead (e.g., wheel weights) in the scrap automobiles from which ASR 

is generated. The EPA recently established a voluntary program for management of 

mercury switches and a regulatory program for management of mercury switches and lead 

waste in processing of scrap automobiles and other ferrous metal scrap. 167 , 168 The 

California DTSC Report also identified issues concerning the quality of the material, 

specifically related to the content of metals (e.g., copper wire scrap,) non-combustible 

material, water, and other undesirable materials (e.g., PVC plastic). The California DTSC 

Report identified specific technologies needed to upgrade the quality of ASR for use in 

cement kilns and evaluated their feasibility. 

4.2.7 Emerging Materials

Other emerging materials identified by cement plant contacts and regulatory agency 

contacts include MSW, agricultural byproducts, scrap carpet; tire fluff, and oil filter fluff.

Municipal Solid Waste

Regulatory agency contacts169 identified MSW as an emerging material and indicated that 

cement plants have expressed interest in burning this material. MSW includes durable 

goods, non-durable goods, containers and packaging, food wastes and yard trimmings, 

and miscellaneous inorganic wastes. According to New Source Performance Standards 

(NSPS) for MSW combustors, an existing cement plant would be permitted to burn up to 

30 percent of MSW as a percentage of total feed rate. A higher throughput would trigger 

the NSPS for MSW incinerators; office paper is technically MSW, according to the 

regulatory definition. 

Agricultural Byproducts

Several cement plant contacts reported that they formerly used agricultural byproducts

but no longer do so because of supply issues.

170 One alternative fuel supplier 171 reported 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

61

that cement plants in the Midwest had been burning off-spec seeds for energy recovery, 

but that this material was only available in [on the order of] 10,000 pound batches and not 

available in a continuous supply. Therefore when the batches of material were used up, 

the cement kilns needed to return to using conventional fossil fuels.

Oil Filter Fluff

Two cement plant contacts

172 reported using oil filter fluff as an alternative fuel. The 

cement plant contacts reported that the supply of oil filter fluff is relatively stable and that 

the material has a relatively high calorific value. 

Scrap Carpet

One cement plant contact 173 reported using scrap carpet as an alternative fuel, consuming 

approximately 2,000 metric tons per year of scrap carpet and other textile materials. This 

material includes old carpet pads, cutting scraps, carpet rolls, and other materials from 

residential and commercial carpet replacement, and is generated by a regional carpet 

supplier. The principal issues with using this material are organizing the carpet 

installation personnel to segregate the scrap carpet from other debris (e.g., nails, metal 

strips) and segregate the material for transport to the cement plant rather than to the 

local landfill where other debris would be transported. The cement plant contact

reported that small carpet installation companies cannot manage this effectively because 

they have less control over their carpet installation personnel than a larger company does. 

For example, the regional carpet supplier deploys their carpet installation personnel from 

central company locations on a daily basis. The cement company is working with CARE to 

organize other carpet suppliers to provide scrap carpet for use as an alternative fuels. 

However, cost of supplying this material is a substantive issue in increasing utilization.

Transportation cost for the scrap carpet is an issue; for example the hauling capacity of a 

truck may be only three to five tons of carpet, vs. a hauling capacity of 20- 25 tons of tire 

chips in the same size truck. As for other non-hazardous solid materials the cost of 

landfill disposal is an important competing factor. Landfill disposal fees in the Western 

U.S. (not including transportation cost) may be as low as $10 per short ton. The cost for 

transporting the scrap carpet and the labor and equipment costs of processing the 

material for utilization in a cement kiln may be higher than the landfill disposal fee. 

However, scrap carpet is not a very dense material and therefore takes up more space in 

landfills than an equal weight of other solid materials, potentially affecting the cost of 

landfill disposal. As for other non-hazardous solid materials, scrap carpet generator 

companies conducting cost-benefit analysis of landfill disposal vs. beneficial use of scrap

carpet would need to consider the sustainability advantages of the beneficial use as well as 

the incurred costs of beneficial use vs. landfill disposal. 

Realff, 2005, also reported that use of scrap carpet as an AFR has the potential to affect 

cement kiln air emissions, because of the nitrogen content of the scrap carpet. Nylon 

carpet residue contains approximately 4.5 percent nitrogen by mass, while polypropylene 

carpet residue contains less than 0.05 percent nitrogen. Therefore, use of scrap nylon 

carpet has the potential to result in increased NOx emissions as compared to use of scrap 

polypropylene carpet. 174
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

62

4.3 Alternative Raw Materials

4.3.1 Cost Issues

Spent Foundry Sand

Several cement plant contacts reported that the cost-benefit analysis for spent foundry 

sand vs. mined sand is not favorable after material acquisition costs, transportation costs, 

screening and grinding costs are considered. Several cement plant contacts reported that 

their plants have phased out or are phasing out use of spent foundry sand because of costquality issues. 

Cost issues associated with the use of spent foundry sand are directly related to the 

geographic location of material generators and cement kilns, and the specific type and 

quality of the spent foundry sand being generated. One cement plant contact reported 

that use of spent foundry sand is “cost neutral” after the transportation cost is considered

175 while another cement plant contact 176 reported that considering the quality of the 

available material and transportation costs, use of spent foundry sand was not cost 

effective for the plant. A third cement plant contact 177 reported that they had identified 

several nearby sources of high-quality spent foundry sand, including a conventional metal 

casting foundry and a fused silica foundry, and that the cement plant was using whatever 

amount of spent foundry sand that these facilities could provide to them. Other cement 

plant contacts reported that they did not have a strong incentive to seek out spent 

foundry sand because mined sand was relatively inexpensive and widely available in their 

region, or that they generated a sufficient amount and quality of sand from companyowned quarries such that they did not need to obtain an additional supply of sand from 

spent foundry sand.

178

 

Another cement plant contact 179 reported that the cement plant’s use of spent foundry 

sand is “minimal” because of a combination of quality and cost issues. This contact 

reported that a supply of spent foundry sand is not available at a reasonable rate, and that 

is difficult to go through the screening process to screen out debris (tramp metal, etc). 

After considering transportation costs and other costs, spent foundry sand is “not a good 

value” compared to the cost of virgin materials.

Steel Slag

No specific cost issues were identified by cement plant contacts related to the use of steel 

slag.

4.3.2 Technical Issues

Spent Foundry Sand

Not every cement kiln can use spent foundry sand or needs to use spent foundry sand; the 

ability of a cement kiln to use spent foundry sand depends on the kiln type and the type of 

spent foundry sand available. Spent foundry sand supplies silica; cement plants that have 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

63

a supply of virgin and other alternative raw materials that have a sufficient quantity of 

silica would not need to use spent foundry sand to supplement the silica content of the 

raw mix. One cement company 180 reported that the company as a whole is phasing out 

the use of spent foundry sand because of air emissions issues concerning carbon monoxide 

(CO) emissions. Some spent foundry sand available to them contains volatile organic 

compounds including the binder materials (oils, phenolic resins) used to make molds. 

Older technology long dry kilns were able to use spent foundry sand without incurring 

increases in CO emissions. As the company converted their cement kilns to one-stage 

preheater designs, the volatile organic compounds in the spent foundry sand started to 

burn off in the cement kiln preheater, rather than in the kiln itself, generating excess CO 

emissions. The CO emissions were such that the cement plant was approaching its overall 

permitted CO emission limit, so the company began to phase out the use of spent foundry 

sand for their new one-stage preheater design kilns. The company’s older long dry kilns 

are capable of using spent foundry sand. Other cement plant contacts 181 reported that 

they have not experienced any issues with use of spent foundry sand resulting in excess 

CO emissions or other air emissions. 

Several cement plant contacts 182 noted the necessity of processing of spent foundry sand 

to remove “tramp metal” (metal chips) that can damage cement plant grinding equipment. 

The material can be screened either at the supplier or at the cement plant. Other spent 

foundry sand applications (e.g., construction fill) are less sensitive to the quality of the 

material. 

One cement company 183 reported a change in kiln design resulted in them phasing out the 

use of spent foundry sand. Older technology long dry kilns were able to use spent foundry 

sand without incurring increases in CO emissions resulting from the combustion of 

volatile organic compounds in the spent foundry sand. However, in the company’s new 

one-stage preheaters design kilns, the volatile organic compounds in the spent foundry 

sand started to burn off in the cement kiln preheater, rather than in the kiln itself, 

generating excess CO emissions. The company’s older long dry kilns are capable of using 

spent foundry sand without creating excess CO emissions. Other cement plant contacts

184 reported that they have not experienced any issues with use of spent foundry sand 

resulting in excess CO emissions or other air emissions. 

Steel Slag

No specific technical issues were identified by cement plant contacts related to the use of 

steel slag. 

4.3.3 Regulatory Issues

Cement plant contacts and regulatory agency contacts reported fewer regulatory issues for 

utilization of non-hazardous solid materials as raw materials in cement production. 

Alternative raw materials (e.g., spent foundry sand, steel slag) have generally fewer 

regulatory issues than do alternative fuels with respect to permitting, performance testing, 

and public perception. For example, air emissions performance testing and modifications 

to the facility air emissions operating permit are generally required for cement plants to 

initiate use of alternative fuel, while cement plant contacts reported that for use of 

alternative raw materials (e.g., spent foundry sand, steel slag) permit modifications and 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

64

performance testing are not necessarily required for cement plants to initiate use of the 

materials. Several cement plant contacts 185 and regulatory agency contacts 186 reported 

that no modifications to plant operating permits were required for the plant to initiate use 

of spent foundry sand, steel slag, or other “non-fuel” alternative raw materials. Initiating 

the use of “non-fuel” alternative raw materials were considered to be an “operational 

change” to the plant and required only a letter to the regulatory agency, not a permit 

modification, provided that no changes to facility emissions or the ability to comply with 

existing permit conditions would result.187

Some cement plant contacts and state regulatory contacts 188 reported that in their states 

sand and other solid raw materials are relatively inexpensive and widely available, and that 

therefore there is little if any cost benefit for cement plants to seek out spent foundry 

sand.189 Competing uses (construction fill, daily landfill daily cover) are less costly than 

transporting spent foundry sand to cement kilns, and there are lower potential 

environmental permitting issues in using the spent foundry sand for competing uses than 

for raw material to cement kilns. 

Some states do not have an active regulatory agency program for managing spent foundry 

sand. Several cement plant contacts reported that in their states management and disposal 

of foundry sand is not highly regulated. Foundries can accumulate the spent foundry sand 

on their property or use the material as a “soil amendment.” A soil amendment is any 

material added to a soil to improve its physical properties. Most foundries, depending on 

regional and contractual variables, do not have a strong incentive to move the spent 

foundry sand offsite. Cement plants incur transportation costs and processing costs to 

obtain and prepare spent foundry sand for introduction into the cement kiln. The lack of 

incentive for foundries to send the spent foundry sand to cement plants and cost barriers 

for cement plants to obtain and process the spent foundry sand decreases the desirability 

of the material as an alternative raw material.190 Unlike scrap tires, however, landfilling of 

spent foundry sand probably cannot be precluded by state or local MSW landfill 

regulations, since landfill daily cover is one of the principal applications of spent foundry 

sand. Daily cover is material placed on the surface of the active face of a MSW landfill at 

the end of each operating day to control vectors, fires, odors, blowing litter, and 

scavenging

4.3.4 Supply/Logistics Issues

Spent Foundry Sand

The supply of spent foundry sand available to cement kilns depends upon the locations of 

and production capacity of foundries in the vicinity of the cement kiln. Some cement 

plant contacts 191 reported that they have contract relationships both with individual 

foundries and with third-party “consolidators” that consolidate spent foundry sand 

generated by multiple foundries into shipments to the cement kiln. Either the foundries 

or the third-party consolidators may process the spent foundry sand (e.g., to remove 

metal, for size reduction) prior to shipment to the cement kiln. Several cement plant 

contacts 192 reported that the supply of spent foundry sand is limited and that the cement 

plants could use more spent foundry sand than is available to them.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

65

Steel Slag

Two cement plant contacts 193 reported using a specific type of steel slag from Japan as a 

clinker additive. Use of slag as clinker additive is outside the scope of this study. One 

cement plant contact 194 suggested that competition from concrete batch plants using steel 

slag as an additive may be affecting the market for steel slag use as a cement kiln raw 

material. Other than supply issues, cement plant contacts did not report any specific 

issues related to use of steel slag as a raw material in cement kilns.

4.3.5 Trends Analysis

It is unclear from information provided by the cement sector contacts for this study 

whether utilization of spent foundry sand in cement kilns will increase or decrease in the 

future. A number of cement plants (and some entire cement companies) reported that 

they are phasing out the use of spent foundry sand as being incompatible with their kiln 

design or because use of the material is not cost effective.195 The number of older 

technology kilns that could easily use spent foundry sand (without preheaters and 

associated carbon monoxide emissions issues) is anticipated to decrease over time, and 

more immediate uses of spent foundry sand, such as construction fill and landfill daily 

cover, may be more cost effective with respect to both transportation costs and material 

processing costs than utilization as a raw material in cement production. However, other 

cement plant contacts reported that they are not able to obtain as much spent foundry 

sand supply as the plant is capable of using 196 or that spent foundry sand that could be 

used in cement production is being landfilled or stockpiled because the state does not 

have an effective regulatory program for managing spent foundry sand.197 It therefore 

appears that there may be local or regional differences in trends for utilization of spent 

foundry sand. 

Utilization of steel slag is anticipated to increase through application of CemStartm and 

similar steel slag processing technologies. TXI transferred the patent for the CemStartm

process to an independent company specifically to promote the expanded use of the 

technology.

4.3.6 Other Emerging Materials

Cement plant contacts reported several other alternative raw materials as being used in 

cement kilns. These include latex paint solids,198 sandblast grit, and storm drain solids 

(generated from municipal storm drain cleanouts).

199 Each of these materials was 

identified by single cement plant. Sufficient information is not available for these 

materials to develop case studies.

5. Conclusions 

This section summarizes the conclusions of the material-specific analysis for each 

beneficial use material studied. These observations are based on the interviews conducted 

with cement plant contacts, regulatory agency contacts, and suppliers, and on additional 

research conducted for this study. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

66

5.1 General Observations

A wide variety of AFR are being used in cement kilns, and the cement sector is being 

aggressive at identifying and testing various types of beneficial use materials. Most of the 

cement plant contacts indicated that their plants, or their companies, have been 

conducting performance testing of new AFR and/or investigating potential suppliers of 

these materials

Cement sector contacts, regulatory agency contacts, and suppliers all indicated that the 

principal focus of cement plants in beneficial use is alternative fuels; there is less of an 

ongoing focus in the cement industry on the beneficial use of raw materials (e.g., spent 

foundry sand, steel slag). This is principally related to cost. For example, several cement 

plant contacts indicated that the use of spent foundry sand was not cost effective for their 

plants because of transportation costs, processing costs, or both, while other contacts 

indicated that their plants are using spent foundry sand on an ongoing basis but could 

replace this material with mined sand or other silica raw materials if necessary. 

Almost all of the cement plant contacts indicated that use of alternative fuels was 

important to the continued competitiveness of their plants. This is reflected in the 

ongoing programs at many cement plants to conduct performance testing of new 

materials and the appearance of third-party alternative fuel suppliers with business plans 

specifically targeted towards cement kilns (as well as the operations of the wholly-owned 

subsidiaries 0f some cement companies that are responsible for sourcing of AFR).

The technical issue of handling materials was a common issue. For instance, a contact for 

a cement plant using wood reported that they are investigating the use of biosolids, but 

that the plant could not use both wood and biosolids because the materials handling 

system cannot handle two different materials simultaneously.200 So a decision to use 

biosolids is also a decision to no longer use wood. Biosolids, scrap paper/wood, and 

agricultural byproducts offer the potential of greenhouse gas emissions offsets for the 

cement plants, from replacement of fossil fuels with biogenic fuels. 

State agency involvement in promoting beneficial use in cement kilns is currently at a 

relatively low level, and the level of state agency involvement varies by material. 

Regulatory agency involvement in managing scrap tires is somewhat higher than for other 

AFR. Many states have statewide programs for managing scrap tires [as reported in the 

RMA 2005 Scrap Tire Markets Report.] For other AFR, some states 201 operate state 

assistance programs and maintain databases of potential suppliers and potential users 

(including cement plants) of these materials, but other state regulatory agency contacts 202

indicated their view that it is more the responsibility of the suppliers and users (e.g., 

cement kilns) to organize themselves and that the responsibility of the agency is (in the 

words of one regulatory contact) to “give alternative materials a fair shake” in the 

permitting process. The overall sentiment was that the economic market is more efficient 

at matching alternative fuel and raw material suppliers and users than regulatory agencies 

would be. However, one key observation is that certain regulatory constraints, such as the 

strict hazardous waste combustor requirements applied to offsite management of CSOS 

when beneficially used as an alternative fuel and raw material, create “false economics” 

and do not allow the true economic opportunities in the cement scenario to be realized. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

67

Both EPA and state regulatory agencies have generally appeared reluctant to provide the 

appropriate regulatory adjustments to address those issues. Where some of those 

alternate fuel materials may currently be subject to RCRA hazardous waste requirements, 

regulatory agency involvement may be necessary to recognize this as a legitimate fuels 

supply business, rather than hazardous waste management, in order for the full beneficial 

use opportunities to be developed. 

The cement industry has the capacity to collect information concerning potential AFR

suppliers on their own either through corporate beneficial use departments, whollyowned and dedicated subsidiaries, non-affiliated commercial suppliers, or individual plant 

purchasing departments, but clear regulatory agency support is sometimes necessary to

allow the AFR use to proceed effectively. 

There is a growing commercial market for “brokers” of industrial byproducts, and they are 

recognizing their potential value as fuel and feedstock to various industry sectors; these 

brokers may consolidate smaller quantities of materials into larger shipments to cement 

plants and may also process the material prior to shipment. For example, in some states203 

third-party brokers are consolidating shipments of spent foundry sand from multiple 

suppliers to supply a cement plant. In the Gulf Coast region there is the potential for third 

party brokers to organize shipments of CSOS from petroleum refineries into consolidated 

shipments to cement plants. The wholly-owned subsidiaries perform this function for 

their company’s cement plants, for example, by organizing and entering into contracts 

with multiple local suppliers of plastics.204 There are also independent alternative fuel 

suppliers that are sourcing various types of alternative fuel materials and using the 

materials to manufacture engineered fuel to specific quality specifications for use in 

cement kilns. 

Significant differences were identified in corporate management of the beneficial use of 

materials among cement companies: some companies205 set corporate benchmarks for the 

beneficial use of materials and transmit benchmarks to their cement plants; for example, 

in some companies 206 different plants are working on different pilot projects with 

different beneficial materials, with the results of the performance tests communicated to 

the company’s various plants. In other companies,207 each cement plant operates more 

autonomously, setting plant-specific objectives for use of AFR.

Significant differences were also identified in cement companies’ interest in expending 

capital to establish or expand use of AFR. Some companies were relatively conservative in 

making capital expenditures to enable or expand the use of AFR; other companies 208 

appeared to routinely make such investments in their plants, in some cases responding to 

specific issues related to material supply.

In general, both cement plant contacts and suppliers indicated that the cost and proximity 

of landfill disposal of beneficial use materials was a significant barrier to increased use of 

materials in cement kilns when landfills are closer and less expensive. This general 

conclusion applies to scrap tires, ASR, biosolids, plastics, spent foundry sand, and other 

non-hazardous materials that can be disposed of [by regulation] in non-hazardous solid 

waste landfills or otherwise used in cement production or other beneficial uses. In 

general, the lower landfill costs (including transportation and tipping fee) are in a 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

68

particular region, the more difficult it is for cement plants or AFR suppliers to divert this 

material from landfill disposal. 

Other factors in local and state government decision making concerning promotion of 

AFRs vs. landfill disposal include the local and state governments’ approach to the “waste 

management hierarchy.” In general, if a waste management hierarchy is implemented as 

government policy at the local or state government level, landfill disposal of materials is a 

less desired option than reuse, recycling, or beneficial use. Therefore government policies 

that actively take into account a waste management hierarchy would discourage landfill 

disposal of materials that could be used as AFRs. Also, local and state governments that 

are implementing regulations to reduce greenhouse gas emissions may also be 

establishing specific “waste diversion goals” to promote beneficial use of materials in 

industrial processes, including cement production, to reduce greenhouse gas (CO2) 

emissions.

Table 10 presents tipping fees for landfills in 2004. Note that total landfill cost includes 

the tipping fee and transportation cost. Landfill costs tend to be lower in the Western U.S. 

(except for California) and higher in the more densely populated Eastern U.S. Several 

cement plant contacts reported that landfill tipping fees in Texas and Oklahoma (not 

including the waste transportation costs) can be as low as $10 per ton.

Table 12. Landfill Tipping Fees , 2004

Region Dollars per

short ton

Northeast $70.53

Mid-Atlantic $46.29

South $30.97

Midwest $34.96

South Central $24.06

West Central $24.13

West $37.74

National Avg. $34.29

Source: National Solid Wastes Management 

Association 2005 Tip Fee Survey (2006)

Much of the AFR being used in cement kilns provide natural synergies [direct correlation] 

between the cement sector and other sectors. These include:

 Automobile Manufacturing: Automobile Shredder Residue 

 Automobile Parts Manufacturing: Plastics 

 Oil and Gas: Refinery Spent Catalyst and CSOS 

 Metal Casting: Spent Foundry Sand

This correlation among sectors provides opportunities for joint projects, based on 

geographic proximity, among the sectors matching up material generators and potential 

users (cement kilns). 

Material-specific conclusions are as follows:
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

69

 Scrap Paper/Wood and C&D Debris 

As discussed above, only one cement plant was identified that is using alternative fuels 

derived from C&D debris; no other cement plants were identified that are investigating 

the use of alternative fuels derived from C&D debris. The principal issue with this 

material is the difficulty in identifying a long-term supply of C&D debris and the difficulty 

in processing the material into a consistent quality of alternative fuel for use in cement 

kilns. The principal issue identified with use of scrap paper/wood is also the difficulty in 

securing a long-term supply of the material. In order to secure long term supply, one 

cement plant identified a wood products manufacturing plant as a source of wood, and 

another cement plant, through a wholly-owned subsidiary, organized a number of local 

suppliers to supply scrap paper and cardboard. Some cement plant contacts indicated 

that they were investigating discontinuing the use of scrap paper/wood and initiating use 

of plastics in part because of the uncertainty in the long-term supply of the scrap 

paper/w00d. 

 CSOS 

The regulatory classification of CSOS as a hazardous waste (RCRA Waste Code K170) is a 

significant barrier to increased beneficial use of this material in cement kilns and other 

applications as an alternative fuel and raw materials. Under the current regulatory 

classification, only facilities that are permitted as RCRA hazardous waste facilities can 

accept this material. Petroleum refinery contacts reported that they are often managing 

this material onsite using thermal treatment (coking) processes, rather than sending the 

material to cement kilns for use as alternative fuel, even though in some cases processing 

the material onsite is more costly than sending the material off site to a cement kiln. 

Petroleum refineries are managing the material onsite in part to avoid classification of the 

material as hazardous waste when shipped offsite, and in part because managing 

shipments of the material as a hazardous waste is difficult from a logistics standpoint. 

Also, the classification of the CSOS as a hazardous waste means that only [the 18] cement 

kilns that have hazardous waste combustor permits can accept the material. Some CSOS 

is sent to cement kilns, but trends data indicate that shipments of CSOS to cement kilns 

are intermittent and have been decreasing (see Table 7). If CSOS was not hazardous 

waste, all cement kilns could use it and the amount available to the market would increase 

because refineries would no longer have the same incentives to manage the material on 

site. 

There are two potentially competing factors related to potential reclassification of CSOS as 

a non-waste material when beneficially used. Reclassification would likely mean that 

petroleum refineries would limit, or cease entirely, managing the CSOS on site based on 

cost and environmental efficiency considerations. It could therefore be anticipated that 

the supply of CSOS available to the market would increase if the CSOS was reclassified as 

a non-waste material. However, reclassification would also likely mean that others could 

also accept the material for use as an alternative fuel. This would potentially increase the 

market competition for the material, although this effect could be lessened by the 

potential increase in the supply of the material. According to refinery contacts, CSOS was 

initially considered for listing as a hazardous waste because the material was being 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

70

disposed of in landfills. Therefore, it is unlikely that any change in the classification of the 

material would permit disposal of the material in non-hazardous solid waste landfills, as 

opposed to using it for energy recovery.

 ASR

The classification of ASR as a “PCB-containing waste” under TSCA is a barrier to use of 

this material as an alternative fuel in cement kilns. Much of this material is being 

disposed of in landfills as a result. ASR is generated from automobile shredders that are 

located throughout the country, and (other than its regulatory classification) would 

represent a widely-available source of high-calorific value material for use as alternative 

fuel in cement kilns. The technologies needed to upgrade the quality of ASR for use in 

cement kilns also represents a potential cost barrier to use of the material in cement kilns.

Modification of the waste classification definitions applicable to ASR may be needed to 

facilitate use of ASR as an alternative fuel in cement kilns. 

 Scrap Tires

Barriers to increased use of scrap tires in cement kilns include negative regional public 

perception concerning such use and the perception that recycling of scrap tires into new 

products (e.g., playground, sidewalk, and other crumb rubber material) is a “higher use” 

for scrap tires. The waste management hierarchy applied to scrap tires to some extent 

depends on the perception and consideration of the calorific value of the scrap tires. The 

“higher use” perception can be reflected in state regulations concerning scrap tire 

management that promote crumb rubber uses while remaining neutral on beneficial use 

in cement kilns. 

Another barrier to increased use of scrap tires in cement production are state and in some 

cases local regulations that allow scrap tires to be disposed of in non-hazardous solid 

waste landfills. This issue could potentially be addressed by coordination among EPA, 

state governments, and the cement sector to establish programs to divert scrap tires from 

landfill disposal, potentially by revising state regulations or establishing or revising state 

scrap tire management programs. 

 Spent Foundry Sand

As discussed above, several cement sector contacts indicated that their plants (or 

companies) are not using spent foundry sand either because the use of the material is not 

cost effective or because the phenolic resin content of the material is not compatible with 

dry kilns with preheater/precalciner design. The cost issues are related to the quality of 

the material and the availability of inexpensive virgin material. The need to screen the 

lower quality spent foundry sand to remove metal and other extraneous materials 

increases the cost of using the material. Some cement plant contacts indicated that they 

are working with local spent foundry sand suppliers to solve the quality issues; other 

cement plant contacts did not express interest in continuing to use the material. Cement 

plant contacts for which their kiln designs are incompatible with the organic compound 

content of the spent foundry sand also did not express interest in continuing to use this 

material. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

71

Another barrier to increased use of spent foundry sand in cement kilns is competing uses. 

Uses of spent foundry sand such as for construction fill are less sensitive to the quality of 

the material, and the locations of these competing uses may be closer to the facilities that 

are generating the spent foundry sand than the cement kiln is. These conditions would 

provide a cost disadvantage to use of spent foundry sand in cement kilns. Also, some 

states do not have active regulatory management programs for spent foundry sand and 

permit the material to be land disposed, or stockpiled on the foundry site. This lowers the 

cost of disposal of the material and does not provide an incentive for foundries to generate 

high-quality spent foundry sand for cement kilns. 

 Steel Slag

Cement plant contacts and regulatory agency contacts did not identify specific issues 

related to use of steel slag as an alternative raw material in cement kilns. 

6. Recommendations/Further Actions

This section summarizes further possible actions that could be taken by cement plants, 

suppliers, and federal and state regulatory agencies to address identified barriers to 

increased beneficial uses of materials.

Regional differences were identified in the use of beneficial materials depending upon the 

availability, cost, quantity and quality of virgin materials and availability, cost, quantity 

and quality of beneficial use (AFR) materials, and also depending upon federal, state, or 

local regulatory frameworks. Such geographic differences suggest that the development of 

recommendations for possible further actions be tested regionally. 

Also, these recommendations for possible further actions consider supply and demand 

issues and associated cost, technical, and regulatory issues; health effects issues associated 

with the beneficial use of materials are outside of the scope of this report, but health 

effects will need to be considered in implementing any recommendations for further 

actions.

SSP Sector Partnerships

 SSP could consider promoting the development of partnerships between the 

cement sector and other SSP sectors; there is a strong interest in examining these 

issues jointly among various sectors. Considering the wide variety of alternative 

fuels and raw materials identified as being used or potentially being used in 

cement kilns, SSP could also consider expanding the types of materials under the 

program’s review.

 SSP could develop partnerships between SSP and state agencies with active 

beneficial use promotion programs and also work to promote the establishment or 

expansion of state beneficial use promotion programs. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

72

Regional Workshops and Pilot Projects

 SSP and the Portland Cement Association could coordinate setting up regional 

meetings and workshops with cement companies, state regulatory agency and EPA 

Regional offices, and beneficial use material suppliers to address barriers to 

increase use and to connect cement plants with potential AFR suppliers.

 SSP could work with OSW and PCA to promote “pilot projects” with specific 

cement plants and AFR suppliers as an outgrowth of the regional workshops.

 With respect ASR and CSOS specifically, SSP should consider initiating meetings 

with other relevant EPA offices to discuss where regulatory classification of these 

materials may impose barriers, prior to coordinating regional workshops or pilot 

projects. 

Examples of potential actions that SSP and PCA could undertake include:

 Promoting a performance test project with a cement company, an ASR supplier, 

and state and EPA Regional offices to obtain data concerning the performance of 

the material as an alternative fuel. This pilot project could potentially be expanded 

to other regions that have refineries generating CSOS and cement kilns that could 

potentially use the material as an alternate fuel and raw material.

 Organizing a workshop to address performance testing issues related to expanding 

use of CSOS to cement plants in the Gulf Coast region. 

 PCA and EPA could potentially jointly develop long-term goals for replacing

conventional fuels and materials with alternatives (e.g. increasing national 

alternative fuel replacement to specify increasing a certain type of alternative fuel

by a certain percentage by a certain year).

 PCA and EPA could consider initiating discussions with State government agencies 

concerning development of more a standardized permitting and performance 

testing approach for alternative fuels in general and “engineered fuel” specifically. 

 PCA and EPA could potentially initiate discussions with State government 

agencies concerning development of a “stewardship strategy” for AFRs, including 

standardized receipt and characterization and testing standards.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

73

7. Appendix A: Case Studies

7.1 Beneficial Use Case Studies

Appendix A presents the results of the material-specific analysis for each beneficial use 

material analyzed for each cement kiln case study. 

7.1.1 Spent Foundry Sand

California Portland Cement Company, Colton CA

The California Portland Cement, Colton CA plant uses approximately 10,000 to 25,000 

tonsiper year of spent foundry sand from multiple suppliers. A third party collects the 

material, screens the material for trash and debris, combines the material into truckloads, 

and delivers the material to the Colton cement kiln site. The use of the spent foundry 

sand has resulted in an overall decrease in raw material costs (after the cost of testing the 

material) of $0.70 per ton clinker. 

Foundry sand is used at the Colton Plant for silica replacement. The Colton Plant quarry 

operation produces high purity limestone, but the limestone has no silica or alumina 

content. Thus, the Colton Plant has to import silica and alumina from spent foundry sand 

and other sources to make their raw material mix. The California Portland Cement plants 

in Rillito AZ and Mojave CA don’t have this issue with the silica/alumina content of their 

limestone.

The Colton Plant does not have as much spent foundry sand as desired, and they also use 

mined silica and diatomaceous earth to supply silica to the raw material mix. The Colton 

Plant’s spent foundry sand supply is limited because there are not enough aluminum and 

steel foundry sand suppliers in proximity. Competition from alternative uses of spent 

foundry makes the material more expensive for the Colton Plant to obtain. There is more 

efficient recycling of foundry sand within the foundry (driven by internal cost), and there 

are alternative uses for spent foundry sand. The overall cost for the Colton Plant to 

acquire the spent foundry sand is $14 per ton. 

The Colton Plant uses spent foundry sand from aluminum and steel foundries. The plant 

does not use spent foundry sand from brass foundries because brass foundry sand 

contains lead; using lead-containing waste would require the plant to obtain a RCRA 

permit. The Colton Plant has not experienced any regulatory issues with aluminum or 

steel foundry sand.

CEMEX, Knoxville, TN

CEMEX operates one preheater/precalciner kiln in Knoxville. The cement kiln uses two 

primary types of spent foundry sand: (1) spent foundry sand from a “typical casting facility 

 

i All “ton” quantities in these case studies are “short tons” unless otherwise specified.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

74

for casting metal parts” and (2) spent sand from a “fused silica” plant, which is used in

manufacturing transistors. The material is more than 99 percent silica, consisting of high 

purity sand mixed with fused silica. CEMEX has not encountered any issues related to 

phenolic resin binders in the spent foundry sand or other effects on air emissions from the 

use of spent foundry sand from the casting facility. 

A broker that works with the cement industry connected CEMEX with the foundry. The 

quantity of spent foundry sand used has been constant over time, and the CEMEX plant 

uses whatever the facilities produce. This source of silica is cheaper than mined material.

The plant operates under air permit conditions including a 12-month “rolling sum” of 

emissions. The emission factors are derived from previous stack tests, including tests for 

total metals. There are NOx, SOx, and CO emission limits in the permit; the 12-month

rolling sum emissions limits in the permit are for lead, mercury, and beryllium. Mercury 

is part of the “raw material substitute” program for the plant. Raw materials, including the 

spent foundry sand, are analyzed quarterly, and an updated alternative materials report is 

completed every month. The plant has not encountered any environmental permit issues 

associated with the use of these materials. Alternative raw materials are subject to 

emission limits; however, as long as the materials are not hazardous wastes, they are 

permitted for use. The regulatory agencies involved in permitting for the Knoxville plant 

include the Tennessee Solid Waste Department and the Knoxville Air District. 

TXI, Midlothian, TX

The TXI Midlothian TX cement plant used spent foundry sand previously, but does not do 

so now because of processing costs, transportation costs, and availability of the material. 

TXI indicated that management of spent foundry sand in Texas is not subject to any active 

state regulatory program. Without an active state regulatory program, foundries have 

little incentive to send this material off site either for beneficial use or disposal. Many 

foundries are piling their spent foundry sand up on their sites, avoiding transportation 

costs. 

One facility in Fort Worth TX processes spent foundry sand for subsequent beneficial use. 

The processing includes screening the spent foundry sand to remove oversized materials 

so that the material can be beneficially used. 

The plant noted several issues regarding the quality of spent foundry sand depending on 

the type of foundry producing the material. Spent foundry sand from aluminum 

foundries has organic compound content, while spent foundry sand from steel and 

magnesium foundries generally does not. The organic compound content of spent foundry 

sand, specifically phenolic resin binders, has been identified as an important issue for 

preheater/precalciner cement kilns because it can generate excess carbon monoxide 

emissions and potentially affect compliance with air emissions permit limits. Phenolic

compounds can also react to form hazardous air pollutant emissions if the compounds 

oxidize in mid-kiln without reaching the combustion zone of the kiln. This can also 

potentially affect compliance with air emissions permit limits. Spent foundry sand may 

also contain chromium, which natural sand does not contain. Therefore use of spent 

foundry sand in cement kilns would cause the state regulatory agency to look at the 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

75

operation and the potential disposition of the chromium with respect to the potential for 

hazardous air pollutant emissions.

The capacity of cement kilns to use spent foundry sand in Texas exceeds the amount of 

available spent foundry sand in Texas; most cement plants charge a recycling fee of $5 per 

ton for spent foundry sand. The transportation cost for the material is also a barrier to 

increased use of spent foundry sand in Texas. 

The increase in fuel prices and the associated increase in transportation costs have led to 

more spent foundry sand being used as a “soil amendment.” Texas policy on spent 

foundry sand does not discourage such use of the material, leading to less material 

available in commerce for potential use in cement production.

Lafarge, Seattle, WA

The Lafarge Seattle cement kiln uses a small amount of spent foundry sand. This material 

is mixed with petroleum-contaminated soils that are used as an AFR. These materials are 

used to replace silica. There are no restrictions on permit flexibility related to the use of 

these materials. The spent foundry sand shipments are set up on a just-in-time delivery. 

The material is not stored on site, and the plant has experienced no difficulty in 

transportation or availability of the material. Approximately 40 tons of the material are 

stored on site at any one time.

The Lafarge Seattle cement kiln is a wet process kiln and has experienced no issues with 

phenolic resin content in the material, excess CO emissions, or clinker quality as a result 

of using the spent foundry sand. To obtain the material, the Lafarge Seattle plant works

through Systech Environmental Corporation, a wholly-owned subsidiary of Lafarge. The 

Systech sales representatives located at the plant help find alternative materials, 

investigate prospective materials, and produce chemical and physical profiles of the 

materials.

Lafarge, Sugar Creek, MO/Tulsa, OK

The Lafarge Tulsa Oklahoma plant formerly used spent foundry sand from a local foundry; 

however, the plant experienced material quality issues with the spent foundry sand and 

discontinued its use by 2004. The Tulsa plant found tramp metal, pig iron and other solid 

materials in the spent foundry sand that got caught in the raw material mill and damaged 

the equipment. There was also a neutral cost to get the spent foundry sand material to 

the plant as compared to mined materials. The Tulsa plant has since installed a screening 

process that can be used to screen out tramp metal. The screening equipment was 

purchased for another application, but could be applied to spent foundry sand. The plant 

is considering using material from the same supplier, and would screen the material first 

to remove tramp metal. The spent foundry sand feed rate would amount to 1 to 2 percent 

of the raw mix, about 60,000 tons per year. 

The Lafarge Sugar Creek Missouri plant uses approximately 3,000 tons or more of spent 

foundry sand annually, depending on the available supply. The plant did not report any 

quality issues or other issues related to use of spent foundry sand. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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Lehigh Cement, Mitchell, IN/ Fleetwood, PA

Historically Lehigh Cement used a lot of spent foundry sand to supply silica to the kilns. 

Lehigh Cement is phasing out the use of spent foundry sand because of issues with excess 

CO air emissions. Spent foundry sand contains volatile organic compounds in the binder 

materials (oils, phenolic resins) used to make foundry molds. As Lehigh Cement 

converted their long dry kilns to one-stage preheaters, spent foundry sand was introduced 

into the preheaters, and the material started to burn off the volatile organic compounds in 

the preheater. Some Lehigh Cement plants adopted voluntary CO emissions limits in 

their permits to avoid Prevention of Significant Deterioration (PSD) air emissions review. 

The spent foundry sand caused CO emissions to increase, approaching the CO l air 

emissions limits. The Lehigh Cement Mitchell Indiana plant is a long dry kiln; this kiln 

technology can still take spent foundry sand; preheater kilns are newer technology; these 

cannot generally take spent foundry sand because of the preheater issues.

7.1.2 Steel Slag

TXI, Midlothian, TX

TXI developed the proprietary CemStartm process that processes steel slag into a raw 

material for cement production. TXI recently sold the patent rights to a separate 

company. TXI researched where the steel plants are in relation to the cement kilns to 

market CemStartm to cement kilns. TXI conducted representative raw mix calculations for 

cement kilns throughout the U.S. and found that there is a constant need for steel slag at 

cement kilns in most regions of the U.S. except for the Northeast where the limestone 

quality is “perfect” for clinker, negating the need to supplement raw mix with steel slag. 

TXI reported that most steel slag generated in Texas is being used as a raw material in 

cement kilns. Chaparral Steel (formerly a unit of TXI, and now a separate company) sends 

their steel slag to TXI. The SMI steel mill in Seguin, TX sends steel slag to Hunter 

Cement. Some steel slag from Chaparral Steel is also going to Ash Grove Cement, located 

in Midlothian. 

The rate of steel slag feed to the TXI Midlothian cement plant is relatively constant, about 

6 percent of clinker production. The maximum feed rate is controlled by product quality. 

TXI Midlothian cement kiln clinker production rate is increased because of the steel slag. 

Previously the production rate was 35 tons per hour of clinker for the wet kiln. TXI added 

2 tons per hour of slag and is now getting 37 tons per hour of clinker. Steel slag also 

improves fuel efficiency and reduces cement kiln NOx emissions. 

According to TXI, with the CemStartm process there is no technical reason for steel mills 

not to send their steel slag to cement kilns. The material can be easily processed for use in 

cement kilns using the process. When analyzing the use of steel slag in cement kilns, one 

must compare the transportation and processing costs with the value of the extra clinker 

that would be produced and the extra tons of cement that would be produced. Most 

cement markets are “sold out” (although this is changing somewhat), so cement plants 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

77

using the steel slag with the CemStartm process would increase clinker production and 

cement production by the amount of steel slag used. 

CEMEX, Knoxville, TN

The CEMEX Knoxville plant uses mill scale, mixed mill scale, and iron slag as alternative 

raw materials. Use of these alternative raw materials is not cost issue but a product 

quality issue. The chemistry of limestone dictates how much sand the kiln needs and how 

much iron the kiln needs. The chemistry of raw materials mix enables CEMEX to meet 

standards for customers, product strength profile, etc.

Mill scale used as alternative raw material in the CEMEX Knoxville plant comes from 

ponds, affecting the quality of the material. Initially, the mill scale material removed from 

the ponds contained some metallic debris. The plant noted that the metal debris got into 

the grinding mill and conveyor belts, damaging the equipment. 

The material used to be landfilled. The material vendor put in screens to screen out 

debris, enabling better handling of product and enabling use in the cement kiln. Still, the 

materials are subject to waste acceptance testing criteria including TCLP {toxicity 

screening) and heavy metals analysis. 

CEMEX identifies sources of alternative raw material through contractors. For the mill 

scale a contractor was working for the supplier and started looking for potential outlets of 

the material. The contractor submitted sample of the material to CEMEX for analysis, 

then CEMEX evaluated the material against their permit conditions and then accepted the 

supply and established a contract.

CEMEX also works with vendors concerning material supply issues. For example, in the 

winter months the vendor may have an extra amount of material. CEMEX stores the

material and, in return, gets a better price for material. There is less supply of the material 

in the summer, so CEMEX handles the surge of material. The storage pile of material is 

turned over within a 12-month period, and material supply changes from week to week or 

month to month.

7.1.3 Scrap Paper/Wood 

Lehigh Cement, Redding CA

The Lehigh Cement Redding, California plant has a long history of burning wood and 

other biogenic materials. The Redding Plant was first permitted in the 1970s to burn 

agricultural byproducts; however, the market for this material in cement kilns collapsed in 

the 1980s because facilities in California started to install wood-fired boilers. The Redding 

Plant then switched to burning rice hulls. Then, rice hull burning power plants were built

in California, and the supply of rice hulls disappeared. It took the Redding Plant four

years to get wood back on line, which was a corporate initiative. The Redding Plant is a 

“small” capacity cement plant (800,000 tons per year of cement) and the plant therefore 

needs to use alternative materials to remain competitive with larger cement plants. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

78

In order to reestablish the use of wood, the Redding Plant needed to build a new storage 

silo and materials handling equipment. The Redding Plant conducted a market 

evaluation; the plant purchasing department sought suppliers. The only material the 

plant identified in the vicinity to replace the rice hulls was sawdust from window frame 

production plants. Sawdust production is tied to the building industry. The sawdust goes 

into the front of the kiln, displacing coal. The wood at the Redding Plant can represent 

between 4 to 15 percent of the plant’s total fuel consumption, depending upon the 

availability of supply.

The Redding Plant needed to be repermitted to burn wood, in part because the plant 

needed to apply capital expenditure to construct the new storage silo, materials handling 

equipment, and associated air emissions control equipment. The amount of wood that 

can be burned is based on the results of the performance tests conducted. Because of the 

repermitting, the plant cannot burn more than 7 tons per hour of wood. Under California 

Law AB2588, toxic emissions law, the Redding Plant could not get a permit to process 

more than 15 percent more wood than the amount of wood tested in the trial burn test; 

the test run was conducted at 5 tons per hour wood. The Redding Plant could permit the 

plant at a wood feed rate of 8 tons per hour if they conducted a new trial burn test, but 

there is currently a lower market supply of wood because of the housing market slump. 

The Redding Plant has a direct contract with the window frame company and is hopeful

that the supply of wood will continue from the window frame company.

The moisture content is important to the materials handling characteristics of the wood 

The Redding Plant had to get new permits to upgrade materials handling equipment to 

keep material dry. This included installation of new baghouse, extended materials 

handling system covers, and upgraded hoppers to keep out rainwater. The sawdust tends 

to seize up in the materials handling equipment when gets wet.

Sawdust, when dry, tends to bridge in pipes, and the dust is explosive, like coal dust. 

Therefore sawdust is difficult to use. Although not a federal regulation, the equipment 

modification required state BACT review, including installation of state of the art dust 

collectors. This made using the material more challenging. Application of the California 

Environmental Quality Act (CEQA) was not required for the wood because sawdust is 

cleaner than coal. The Redding Plant has evaluated switching to plastics (the plant could 

not use plastics and wood simultaneously because of limitations of the materials handling 

system). If the plant switched to plastics, or MSW, CEQA would need to be implemented 

because the perception is that these alternative fuels may not be cleaner than coal. The 

CEQA Environmental Impact Report (EIR) and subsequent permitting could take several 

years to complete, and even after the process is complete the Shasta County Supervisors 

would have to vote on the issue, lending uncertainty to the process.

Lehigh Cement, Fleetwood, PA

The Lehigh Cement Fleetwood plant used approximately 9,000 tons of wood in 2007, 

predominately ground scrap creosote-treated wood. The plant initiated use of wood five 

years ago. The supplier is a local company that started as a landscaper and became a 

wood processor; the company approached the Fleetwood plant and asked whether the 

plant could burn wood. The Fleetwood plant then ran a trial to establish the maximum 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

79

burning rate in the kilns, showing that two tons of wood were needed to offset one ton of 

coal (wood provides 6,500 BTU per pound, and coal provides 12,000 BTU per pound).

The Fleetwood plant obtained plan approval and established a contract agreement with 

the wood processor. The supplier sources the wood, processes the wood, loads the 

processed wood onto trailers, and delivers the wood to the plant on as as-needed basis.

A large capital expenditure was needed to install an “alternate fuel dosing system” for the 

wood. This system consists of trailers that are run hydraulically through the plant process 

control system. The wood is unloaded to a bin and conveyor. The bin has a load cell on it, 

and the conveyor feeds a “Pfister Feeder” that takes the ground wood into rotary feeder 

and blower. The wood blows into the front end of the kiln right above the coal 

pipe/burner. The maximum wood feed rate is two tons per hour for each kiln, four tons 

per hour total. The feed rate can be adjusted by adjusting how fast or slow the dosing 

equipment runs. There is a separate set of feed equipment for each kiln. The plant noted

technical issues with handling wood, particularly with respect to moisture. If the wood 

gets wet it reduces the calorific value of the material. 

The permitting process took several years to complete. In order to obtain plan approval, 

the plant submitted a “coproduct determination” application through PADEP to get 

approval to use the wood as a “coproduct.” The PADEP Air Board required that the 

material have a minimum of 5,000 BTU per pound of heat input available to prevent 

“sham recyclers.” 

As a permit condition, the plant needs to analyze the wood for metals content. This 

includes weekly sampling. The operating permit requires sampling of each load of wood. 

The samples are composited into weekly load samples for calorific value, proximate and 

ultimate analysis, metals, and other constituents. There are no specific permit limits for 

these parameters but the plant is required to report the analysis results to PADEP. PADEP 

could use sampling and analysis reports to provide limits, but the agency hasn’t done so, 

because cement plants doesn’t create ash. If the wood was burned in a wood-fired boiler 

the permit conditions would be different.

The supply of wood is now fairly constant, but the plant anticipates that the supply may 

disappear sometime in the future. Issues associated with purchasing wood include the 

difficulty of maintaining wood supply from an economic standpoint. Many companies 

are looking for wood supply. Wood generators used to pay the cement plant to accept the 

material; now the cement plant pays the supplier for the material, and the long-term 

supply of the material is questionable. 

The alternate fuel dosing system equipment could be expanded to other alternative fuels. 

The Fleetwood plant is obtaining leads from the corporate level concerning utilization of 

plastic; Lehigh Cement plants elsewhere in the US or in Europe also put out ideas that 

other plants can use with respect to alternative fuel uses.

Lafarge, Sugar Creek, MO
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The Lafarge Sugar Creek Missouri plant initiated use of plastics, cardboard, rubber scrap, 

paper, and related materials in March 2008. These materials are being obtained from 

generators in the greater Kansas City metropolitan area. The plastics, rubber, cardboard, 

paper, and related materials are all being obtained through direct contracts through 

different suppliers. 

The Lafarge subsidiary Systech conducted a market study to identify suppliers, working 

with a non-profit “byproducts synergy group” to identify markets for alternative fuel 

materials. Systech supplies hazardous waste and non-hazardous alternative fuels to the 

Lafarge plant. The Lafarge plant has also established contracts to use landfill gas from 

local landfills as an alternative fuel. 

The target for the alternative fuel use is 40 to 50 percent of total BTU input to the kiln; 

this will involve ramp up over two to three years; the interim target for the end of 2008 is

20 percent replacement of total BTU input including landfill gas (10 percent) and solid 

fuels (10 percent). 

A permit modification of the plant air permit was needed to clarify what alternative fuels 

the plant could use, including plastics, paper, cardboard, and related materials. A permit 

was also obtained from the local government; this is a “special use permit” which allows 

the city to tax the use of alternative fuels as a “solid waste facility” operation. Public 

notification was required, but no public hearing was requested. No changes in air 

emissions permit limits were needed to introduce plastics, only changes to the list of 

materials identified in the operating permit that could be burned. The permitting process 

for the plastics was initiated earlier than the Prevention of Significant Deterioration (PSD) 

permit process for the entire plant; otherwise the State permitting agency might have 

been able to ask for lower emission limits in the PSD permit. However, other plants 

performance tests showed no increase in emissions or reduction in emissions from plastics 

use.

California Portland Cement, Rillito, AZ / Mojave, CA

California Portland Cement reported that their Rillito AZ and Mojave CA cement plants 

are permitted to use wood, and have used wood in the past, but that there is little supply 

of this material in the areas of the two plants and neither plant is using wood at present. 

The two plants are also permitted to use on-spec surplus oil and surplus jet fuel.

7.1.4 Refinery Spent Catalyst and CSOS

Gulf Coast Petroleum Refineries (Generators)

Clarified Slurry Oil (CSO) is produced at refineries in the Fluidized Catalytic Cracker 

(FCC) process. The catalyst used results in an alumina/silica-based fines material with no 

heavy metals content that is suspended in the CSO. When the CSO material is removed 

from the FCC unit into refinery tankage (slurry oil tanks), some catalyst fines are 

entrained in the product stream, which later settle in the slurry oil tanks. 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

81

As noted above, the CSO is produced with inherent solids content; the solids that are 

settled out of the CSO are classified as Clarified Slurry Oil Solids (CSOS). CSO is sold 

directly to various energy markets as a fuel material (i.e., as a refinery product) with 

various ash specifications (generally representing the solids content). As the fines (i.e. 

ash) content increases in the CSO above certain ash specifications, market outlets become 

limited and refineries cannot sell the material directly into conventional markets such

marine fuel (i.e., bunker fuel) or carbon black feedstock. Therefore there is an economic 

incentive for the refineries to separate the CSO from the CSOS. Refineries let the CSO 

material settle in the slurry oil tanks, the oil is then pumped out and is sent to traditional 

energy markets as a refinery product. The value of the CSO as a refinery product is based 

on the solids content, the higher the solids content, the lower the value of the material. 

Once the solids content of the CSO reaches about 0.7 percent the value of the material to 

potential customers decreases substantially.

The settled material remaining at the bottom of the slurry oil tanks is considered CSOS –

CSOS is a listed hazardous waste (K170), Historically this material was landfilled;

however, now refineries avoid utilization of landfills as a matter of corporate 

environmental policy. Centrifuged CSOS “cake” can fail EPA land disposal restrictions test 

for semivolatiles, and the material cannot in any case be sent to a landfill. The material is 

generally managed onsite at the refinery, such as by reprocessing the material back into 

the cokers (thermal treatment). One incentive of refineries reinjecting the CSOS into the 

cokers is that the refineries then do not have to classify the material as a waste. Since 

material processed onsite at the refinery is not classified as a “waste,” it is not reportable 

wither in the RCRA Biennial Hazardous Waste report or the annual TRI reports. 

Some refineries have sent their CSOS (as a hazardous waste) to cement kilns for energy 

recovery. Systech (Lafarge) cement kilns in Fredonia KS and the TXI cement kilns in 

Midlothian TX, among other cement kilns, are permitted to accept K170 hazardous waste. 

The CSOS provides the cement kiln with both energy content and raw material content 

(alumina, silica). Typically cement kilns first analyze an initial sample of the material to 

ensure that they are permitted to accept the material, and then may analyze additional 

samples in the event that the characteristics of the material change (e.g., there is a change 

in the solids content of the material as generated by the refinery). Data concerning the 

amount of CSOS (K170 waste) transferred to cement kilns for energy recovery is included 

in the main section of this report. 

The CSOS is not generated on a continuous basis; tank cleanouts are conducted as a batch 

process. Typically, refineries remove CSOS from their each of the slurry oil tanks every 

ten years or so. These settling tanks are on the order of one million gallons each; a typical 

large refinery can generate over one million pounds of K170 waste per year depending 

upon the schedule of tank cleanout. The CSOS material is typically slurried out of the 

settling tank and the solids are sent to 20 cubic yard roll-off boxes. The liquid becomes 

(low solids content) CSO product, and the solids removed become CSOS.

According to refinery contacts there is an outstanding and fundamental question 

regarding the point at which the CSOS becomes “hazardous waste” in the CSO settling 

and CSOS removal process. CSO is not hazardous waste, it is a refinery product, however, 

CSOS is classified as a hazardous waste. “Wet” FCC catalyst that is removed directly from 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

82

the fluidized catalytic crackers during catalyst replacement isn’t classified as hazardous 

waste either, and cement kilns use this material as a non-hazardous alternative raw 

material. Spent FCC catalyst is classified in Texas as “Class II non-hazardous waste” and is

being recycled into materials used for road bed construction in Texas. This material is a 

major alternative raw material from petroleum refining to cement manufacturing. 

A fundamental regulatory question is where (at what physical location within the CSO 

settling tank) is the catalyst material first classified as hazardous waste? According to the 

refineries, EPA OSW has not directly answered this question. The refineries suggested 

that the most direct approach to defining CSOS as a non-hazardous waste is through the 

EPA “definition of solid waste” (DSW) regulatory process. If CSOS is deemed by EPA not 

to be a “solid waste” when beneficially used, the material inherently cannot be classified as 

a hazardous waste either. The refineries pointed out that CSOS was originally listed by 

EPA as a hazardous waste because of its chromium content and poly-aromatic 

hydrocarbon (PAH) content, and that the material was originally considered for listing as 

a hazardous waste because the material was historically being landfilled. However, the 

PAH content in this material (just as the PAH content in any other commercial fuel) is not 

a technical issue for processing of CSOS in cement kilns for energy recovery. Therefore, 

according to refinery contacts, there is a basis for reclassifying CSOS used as an alternative 

fuel or raw material as a refinery product rather than as a solid waste.

Reinjection of CSOS into the cokers is recognized by refineries as a less optimum use than 

cement kilns would be, but refineries do this to avoid having to classify and report the 

material as a hazardous waste. Refineries have to use energy to prepare the CSOS material 

to go back to the cokers or incur the cost of centrifuging the material. They would 

generally prefer being able to sell the material to cement kilns without further processing.

The refineries have identified transport trucks that can transport unprocessed CSOS as a 

“free-flowing” material. Such cost savings are of no value, though, as long as CSOS is 

classified as a hazardous waste. Refineries have estimated that if the CSOS were not 

classified as a hazardous waste the refineries could save more than $1 million per tank 

cleanout from the increased value of the CSOS and avoidance of the onsite management 

costs (i.e., the processing cost of slurrying the material out of the tank and centrifuging 

the material for reinjection into cokers). The cost of sending the CSOS to a hazardous 

waste landfill is about $150 per ton. Therefore, refineries are incurring higher cost to avoid 

having to dispose of the CSOS as hazardous waste in landfills. 

Refineries have been discussing CSOS supply with cement companies. The acidity of the 

CSOS has so far not been an issue for the cement kilns; however, cement kilns as 

customers want to know the sulfur content, mercury content, and calorific value of the 

CSOS, and whatever other characteristics of the material that the cement companies could 

impact air emission control system. The cement kilns want material that is in the range of 

9,000-10,000 BTU per pound, and can accept material with up to 20 percent solids 

content. However, centrifuged CSOS (which is about 70 percent solids) can range from 

8,000-9,000 BTU per pound, because the centrifuging process removes some of the oil 

content (the slurried material prior to centrifuging is about 20 percent solids). The 

centrifuged CSOS can be transported to cement kilns on trucks in roll-off boxes. The 

centrifuged material is tipped into a screw conveyor and mixed with other liquids at the 

cement kiln to make a slurry to inject into the cement kiln.
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The refineries noted that because of the batch nature of the slurry tank management 

process that generates CSOS, a single refinery would not generate sufficient material to 

supply a cement kiln on a continuous basis. However, the refineries also noted that if 

several refineries coordinated their tank cleanout schedules and perhaps also worked 

through a third party consolidator, the refineries collectively could generate sufficient 

material to continuously supply a cement kiln. Refineries are also developing methods of 

modifying their settling tank operating procedures; rather than operate the settling tank 

to build up solids (CSOS) and allow them to settle, the tank could be operated with CSO 

with higher solids content without letting sediment build up in the tank. The operating 

concept is to sell the CSO with the higher solids to markets (e.g., cement kilns); maybe 

then the refineries pump out solids once a year rather than once every ten years.

Refineries may also contract out the management of the settling tanks to third parties. 

The third party would manage removal of the material from the tank and return the 

“empty tank” to the control of the refinery. 

The refineries indicated that transportation costs preclude long-distance transport of 

CSOS, but that the material can be transported on a regional basis. The refineries 

supported the concept of a regional workshop with the cement companies to discuss 

generation and management of the CSOS. 

Motiva, Norco LA (generator)

Motiva Norco typically sends 4,000 tons per year of FCC catalyst to the Holcim Theodore 

cement kiln rather than to a landfill. Since the material is a dusty powder, it is managed 

and transported in pneumatic trucks. This form is compatible with the pneumatic feed 

system at the kiln and maximizes the tonnage per truckload. Overall economics make this 

practice competitive with landfilling. The spent catalyst material is about 75% aluminum 

oxide and silicon dioxide. 

The challenge in using the material was to set up a management system that could turn 

several smaller loads of granular or damp catalyst material into a larger load of uniform 

composition that could be easily transported and handled in silos, conveyor belts, and 

pulverizers of the cement kiln. The concept of stockpiling and mixing the materials 

together worked to achieve the uniformity and handling properties needed. In addition, 

reusing the larger load was cheaper or competitive with the cost of landfilling. Motiva

conducted trials to demonstrate material compatibility over a period of many months. 

Motiva Norco initiated use of this material as a kiln feedstock when it barged 3,900 tons of 

a mixture of spent material to Holcim Theodore in August, 2006.209

Refineries generate a variety of materials (spent sandblasting media, granular catalyst 

beads, support balls, catalyst fines filter cake) that can be commingled to achieve a 

mixture that can be easily managed by conveyor belt systems. In addition, commingling 

enables blending of the chemical properties so that the material becomes more uniform 

chemically and physically. Stockpiling materials over several months promotes uniformity 

and large enough quantity to facilitate the variety of catalysts and other materials 

generated by the refinery. 
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Marathon Oil, Houston TX (generator)

Marathon Oil has seven refinery locations: St. Paul Park, MN; Detroit MI; Canton OH; 

Robinson IL; Catlettsburg KY; Garyville LA; Texas City TX. The Marathon Oil refineries 

generate CSOS. The slurry oil tanks are “flow through units” in which the CSOS collects. 

The slurry oil tanks are typically cleaned out on 10-year cycle. CSOS can be a difficult 

material to handle since it may be thick and sticky or gummy. In some cases, the material 

needs to be “excavated” from the slurry oil tanks. Less labor is involved with continuous 

slurrying rather with periodic cleanout. Refinery service companies have proprietary 

technologies for slurry oil tank management, and some refineries are changing practices 

to continuously remove solids from the tanks rather than removing the solids periodically. 

This is referred to as “continuous slurrying.” However, Marathon Oil is not yet convinced 

that these proprietary processes are proven technology and is still investigating them. 

One Marathon refinery conducted slurry oil tank cleanout projects in 2001, 2002, and 

2008. This refinery generated approximately 4 to 5 million pounds of CSOS per tank on 

cleanout; another refinery removed almost 7 million pounds of CSOS material in 2007. 

This refinery, in Illinois, shipped the CSOS to Canada. Canada permits landfilling of this 

material after stabilization. There is no land disposal ban in Canada at present, but the 

CSOS is still classified as a hazardous waste in Canada. Land disposal restrictions are 

coming into effect in Canada in 2009, and material would then need to be treated before 

disposal.

The Marathon Oil refineries in Detroit, MI, Catlettsburg, KY, and Robinson IL, are within 

reasonable transportation distance to the disposal facilities in Canada. Marathon Oil is 

continuing to work with disposal facilities in Canada to meet the land disposal ban 

requirements. The material first would be treated in the U.S. Alternatively, starting in 

2009 the material generated by the Illinois refinery could be incinerated in US. However, 

hazardous waste incineration cost is 2 to 3 times more than landfill cost.

Marathon Oil has established a corporate goal for waste management to choose onsite 

management first; then fuel blending for energy recovery; then disposal in a landfill or an 

incinerator. 

Marathon also operates two refineries in Gulf Coast, Garyville, LA and Texas City, TX.

These refineries have not conducted tank cleanouts in the past seven or eight years. 

Previously the Gulf Coast refineries either disposed of the CSOS through incineration or 

by transport to Canada. The Texas City refinery has worked with the Clean Harbors 

hazardous waste incineration facility in Deer Park TX for incineration of CSOS. Clean 

Harbors or a subcontractor is also the transporter of the CSOS as a hazardous waste 

transport common carrier.

Marathon has investigated sending the CSOS to cement kilns for energy recovery. The 

CSOS material is a “solid” at certain conditions, but it can be liquefied depending upon 

how much oil is left in it. Marathon refineries could slurry the material and ship the 

material to a fuels blending facility in a tanker truck. The blending facility would need 

“stirred tank” to process the material into alternative fuel. Marathon has had discussions 

with vendors, but has not done any projects with them yet.
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Some of this CSOS waste from the St. Paul Park, MN refinery is generated on a continuous 

basis; the generation rate is approx. 1,000 pounds per month. They will generally try to 

recover oil from the CSOS and return that oil to the refinery for processing, using a sieve 

trap to filter the oil; the filter collects fines from oil, and the fines go into a drum. The 

CSOS generated from this refinery has more oil in it than CSOS generated at other 

Marathon Oil refineries because of the continuous slurry processing. CSOS has been sent 

from the St. Paul Park refinery through SYSTECH to the Lafarge Fredonia KS cement kiln.

The Garyville LA refinery is considering continuous slurrying technologies. A refinery 

service company (TRADEBE Company) has a proprietary technology for slurry oil tank 

management. Under this proposal the service company, as a third party, would manage 

the tank for the refinery. The Garyville, LA refinery has a secondary oil recovery unit that 

should be able to treat the CSOS from tank cleanouts on site. This is high temperature 

sludge treatment unit. Marathon is investigating installing a similar process at 

Catlettsburg KY refinery. The Garyville refinery process treats the API separator sludges 

and other refinery wastes. The CSOS would be a small part of the total feed to the sludge 

treatment unit.

Marathon Oil also generates non-hazardous spent FCC catalyst and is looking to send this 

material to cement kilns also. The Texas City refinery generates approximately 11,000 tons 

per year of spent FCC catalyst. This material is now being landfilled at a cost of $20 per 

ton.

Ash Grove Cement, Foreman AR; Chanute, KS

Ash Grove Cement operates hazardous waste-permitted cement kilns at Foreman AR and 

Chanute KS. These facilities are permitted to accept hazardous wastes, including CSOS, 

and occasionally accept CSOS for use as an alternative fuel. These facilities formerly 

accepted refinery waste “tank bottoms”, which were delivered to the cement plants in roll 

off boxes. Ash Grove ceased accepting this material when the regulatory status of the 

material changed in 1995 and the material was deemed non-hazardous waste. Ash Grove 

could no longer charge a fee to accept the materials, and therefore the cost of continuing 

to use the material as an alternative fuel was cost-prohibitive.

Ash Grove has maintained permits for burning hazardous waste in the Chanute KS and 

Foreman AR plants since mid-1980s. The Chanute plant obtained the first “Boiler and 

Industrial Furnace Rule” (BIF) permit issued in the U.S., and the Foreman plant obtained a 

BIF permit shortly afterward. The BIF Standards were replaced by the Hazardous Waste 

Combustor (HWC) MACT standards, so all of the hazardous waste-burning cement kilns 

were required to obtain a new permit. Ash Grove rebuilt the Chanute plant after the HWC 

MACT standards were issued, and the Chanute plant had to comply with the new HWC 

MACT Standard at startup in 2001. 

The number of cement kiln hazardous waste combustors has been decreasing nationwide 

because of public perception, and EPA enforcement and regulatory requirements. Public 

perception can affect the ability of cement kilns to use alternative fuels and particularly 

solid and hazardous wastes. For example, Montana has state regulatory requirements 
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86

prohibiting use of alternative fuels that are solid wastes in cement kilns. Montana citizens 

in particular are very active, and oppose even using scrap tires in cement kilns. There are 

now 18 permitted hazardous waste combustor cement kilns in the U.S.

The cost for maintaining a hazardous waste combustor permit includes the cost of 

monitoring and testing. This includes performance testing (stack testing) under the 

hazardous waste combustion NESHAP. Routine testing is required every 2.5 years, full 

Comprehensive Performance Testing (CPT) is required every five years, and full risk 

assessment is routinely required every 10 years. This involves reevaluating the prior risk 

assessment for the facility, conducting a screening-test risk assessment, evaluating any 

changes in the emissions and how changes may affect risk assessment results. Either the 

facility passes the risk screen or has to revise the risk assessment. Such revisions are an 

expensive process. 

The cost for obtaining a hazardous waste combustor permit for a newly-permitted cement 

kiln would be on the order of several million dollars including permitting, risk assessment, 

and performance testing. Cement plants that are not already permitted would not spend 

several million dollars to obtain a new hazardous waste combustor permit just to burn 

refinery CSOS. It is highly unlikely that any cement plant that had not been burning 

hazardous waste prior to the HWC MACT standards (i.e., the cement kiln was previously 

permitted under the BIF rules) would obtain a hazardous waste combustor permit; this 

would be difficult both from a public perception standpoint and from a cost standpoint. 

Therefore, the number of cement kilns permitted as hazardous waste combustors is not 

expected to increase.

Ash Grove uses a third-party supplier (Cadence Environmental Energy) to supply 

alternative fuels to their cement kilns and does their own fuel blending. Cadence has no 

physical facilities; they operate sales staff and call on large hazardous waste generators, 

facilities that are producing hazardous waste manifests. Cadence is an independent 

company, not a subsidiary like Lafarge/Systech and Holcim/Geocycle. 

7.1.5 Wastewater Treatment Sludge (biosolids)

CEMEX, Victorville, CA; Vexor Fuels, Medina OH

Vexor Fuels, an engineered fuel supplier to cement kilns, conducted a performance testing 

using biosolids at the CEMEX Victorville, California cement plant. The performance test 

baseline was a kiln feed rate of 10 tons of coal per hour; using biosolids the coal feed rate 

dropped from 10 to 3 tons per hour, with good emissions results. 

A driver for biosolids beneficial use in California is landfill costs. Generators cannot 

landfill biosolids in California. The material has to be first dried at temperatures of at 

least 60 ° C to generate “Class A biosolids.” Energy is needed to dry the material. Some 

biosolids generators are using a combination of filter presses and driers to dry the 

material. The dried biosolids has good ash content for cement kilns, including silica. The 

dried biosolids has 7,000-8,000 BTU per pound. The transportation cost of the dried 

material is also lower; generators are not paying to transport the water. 
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Vexor Fuels also identified a number of other ongoing biosolids projects, including a New 

Jersey project to dry biosolids to the consistency of sand; this project may be supplying 

cement plants in Evansville IN and Union Bridge MD. Vexor Fuels also reported that the 

Union Bridge MD cement kiln is obtaining biosolids from Baltimore City. The Synagro

Company is drying the material for the Union Bridge cement kiln. 

Lehigh Cement, Fleetwood, PA

As discussed above, the Lehigh Cement Fleetwood PA cement kiln is investigating the use 

of biosolids potentially as an alternative to wood. The plant is currently conducting a trial 

to burn dry biosolids from municipal wastewater treatment plants. There is less moisture 

in biosolids (less than 10 percent) than there is in wood; the calorific value is about the 

same as wood, and the economics are about the same as wood.

The Synagro Company already has sludge dryers on line and is putting more dryers on 

line; the City of New York already has sludge dryers on line. The Union Bridge MD plant 

is already permitted to burn this material; 

The Fleetwood plant considers biosolids to be a potential future material, and considers 

wood to be a past material to be phased out. Permitting of biosolids may not be any 

different than permitting wood; the plan approval for this material has been accepted by 

PADEP, and local municipalities are already on line to provide biosolids.

Lehigh Cement, Redding, CA

The Lehigh Cement Redding plant is evaluating use of biosolids, but has not conducted 

any performance testing. The plant material handling system, which is used now for wood 

(sawdust), could also be used for biosolids but the Redding plant considers sawdust to be 

a more secure market at the moment. The Redding plant expectation is that public 

involvement for biosolids would be more difficult than for sawdust. The plant can’t burn 

sawdust and biosolids at the same time using the same materials handling system s0 the 

plant would have to give up burning sawdust to burn biosolids. Redding has a population 

of approximately 80,000 people; Shasta County has a population of approximately 150,000 

people. Redding is two to three hours from Sacramento and Bay Area, which are the 

major sources of biosolids in the area. There would therefore be additional materials 

transportation costs to obtain a sufficient supply of biosolids for the plant. The sawdust 

generator is much closer to the Redding plant than are the biosolids generators. 

7.1.6 Plastics 

Lafarge, Sugar Creek, MO

The Lafarge Sugar Creek Missouri plant initiated use of alternative fuels including paper, 

cardboard, plastics, and related materials in March 2008. The plastics are not derived 

from C&D debris or post-consumer plastic (municipal solid waste) but from industrial 

plants. One issue that the cement plant encountered with the plastics was how to get 

plastics sorted adequately. The cement plant needed to develop an understanding of the 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

88

industry practices and design a sorting process so that PVC plastics are separated from the 

other plastics. 

The Sugar Creek plant permit has a chlorine limit, one reason why PVC plastic is not 

desired. The plant runs tests on the plastics streams for a number of characteristics 

including chlorine content and hazardous constituents. The plant will reassess the 

materials acceptance procedures as plastics shipments start coming in from different 

suppliers, but the intent is not to sample each and every incoming load considering that 

there maybe ten or twenty different suppliers with separate contracts.

Plastics shipments are processed on site, with a “two path shredder” system to 2 inch 

minus size. The materials handling system includes a warehouse, and storage and 

conveyor systems to transport the material to the preheat tower. The plant spent on the 

order of $7 million for capital equipment. The original market studies were initiated in 

April 2006 and the plastics came on line in March 2008. 

TXI New Braunfels, TX

TXI is working on a demonstration project at their New Braunfels, TX plant with company 

that procures plastics for cement kilns. TXI previously conducted a performance test in 

Midlothian using refuse-derived fuels. The refuse-derived fuel test was conducted with 

material from Minneapolis for a thesis test in 1993. The test demonstrated that the 

cement kiln could burn RDF within permit limits and without an increase in pollutant 

emissions. New Braunfels is scheduled to conduct a trial burn using RDF in mid-2008. 

One barrier for cement kilns using RDF in Texas is that it is very inexpensive to landfill 

MSW plastic material. Landfill costs in Texas can be as low as $10 per ton. Therefore, it 

takes a lot of momentum and incentives to get a municipality to sort plastics to make 

RDF. Plastics must be sorted separately from general trash; chlorinated plastics and nonchlorinated plastics must be sorted separately to make RDF for cement kilns. Municipal 

governments would bear the capital and operating cost of sorting the plastics, TXI is 

investigating how to collaborate with municipalities and provide incentives to get 

municipalities to do this. The sorting would eventually pay for itself in fuel and 

potentially also carbon cost; use of RDF as an alternative to landfilling the MSW is a 

climate change issue for avoiding generation of landfill gas CO2 and CH4.

Lehigh Cement, York, PA

Vexor Fuels manufactured “plastic fuel” for Lehigh Cement for a performance test and the 

test was successful. However, Lehigh Cement initially could not obtain a sufficient 

amount of plastics from the market for full-scale introduction of plastics because the 

plastics generated in the local area are being recycled into new plastics. This is a waste 

management hierarchy issue, and is common to other alternative fuel materials that can 

be recycled into new products.

The Lehigh Cement plant in York Pennsylvania is a White Cement plant. The York plant is 

about 1/10 the size of a gray cement plant. The York plant uses plastics as an alternative 

fuel. This material is a high-calorific value material, but Lehigh needed to organize 10 
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89

suppliers to get sufficient quantities of the material for the York plant. It would be more 

difficult to organize a sufficient number of suppliers to supply a gray cement plant with 

plastics than a white cement plant 1/10 the size. These plastics being used are not 

recyclable and otherwise would have been landfilled; i.e., these are materials that would 

not otherwise get into the recycling stream. The material is received at the plant already 

shredded.

Initially the plant had a supply problem with the plastics supply; has worked out this 

problem and is now working on technical issues. For example, the existing conveyor 

system is not adequate to convey material, delivery feed problems being addressed. White 

cement plants are even more difficult to feed alternative materials than gray cement 

plants, because white cement plants cannot feed anything that would affect the whiteness 

of the cement. 

Pennsylvania Department of Environmental Protection

The Pennsylvania Department of Environmental Protection (PADEP) has a grant-making 

economic development agency that works with AFR generators but does not have a very 

active market program to identify suppliers and users of plastics. One view is that the 

private sector is better at matching suppliers and users than agencies are. The PADEP 

contact did acknowledge that MSW plastics recycling rates are not high in Pennsylvania 

and that too much of this material going to landfills. This material could otherwise be use 

as alternative fuel and reduce the demand for fossil fuels. State/local governments in 

Pennsylvania are currently recycling only plastics recycle grade 1 and plastics recycle grade 

2. Existing recycling processes cannot segregate plastics recycle grade 5 and plastics 

recycle grade 6 from the plastics stream. This type of segregation is needed for 

segregation of chlorinated plastics from non-chlorinated plastics because chlorine affects 

the quality of the cement.

Permitting for alternative fuels for the Lehigh Cement plant did not encounter much 

opposition. The plant is subject to PCDD/PDCF limits; but these emissions are lower with 

alternative fuels than with coal. In addition, there are fewer “shooting events” (startups 

and shutdowns) with alternative fuels than with coal. If a cement kiln is contracted to 

make 100 tons of clinker, the kiln potentially needed to make 120 tons if startup and 

shutdown makes 20 tons of off spec product. The use of alternative fuels makes the quality 

of fuel more consistent, and therefore less off spec product is produced.

7.1.7 Scrap Tires

Holcim/Geocycle, Midlothian TX/Ada OK

Geocycle is a wholly owned subsidiary of Holcim and is responsible for sourcing and 

processing alternative fuel and raw material feedstocks and supplying the Holcim cement 

plants with alternative fuels and raw materials. Both the Midlothian Texas and Ada 

Oklahoma cement plants are completely non-hazardous with respect to the materials that 

the cement plants are permitted to accept. 
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The Midlothian plant is primarily a coal-fired plant; the plant started using petroleum 

coke last year. The Midlothian plant includes two kilns, each a four-stage preheater 

precalciner kiln. The current plant fuel mix includes:

 20 percent petroleum coke, 

 15 percent alternative fuels 

 Remainder coal

The Ada plant is primarily a coal-fired plant. The plant includes two wet process kilns. 

The current plant fuel mix includes: 

 Petroleum coke 25 percent

 Alternative fuels 20 percent (almost all tires)

 Remainder coal primarily

The Midlothian plant is currently coprocessing tire chips; wood, spent activated carbon, 

spent filter cake solids, and oil filter fluff (described below). The Midlothian plant is also 

permitted to coprocess used oil, glycols, and glycerin. In terms of calorific value, the 

alternative fuels used in the Midlothian plan are primarily TDF, oil filter fluff, and wood. 

TDF and oil filter fluff are higher percentage in terms of heat input because these 

materials have a higher calorific, wood is a lower percentage in terms of heat input 

because wood has a lower calorific value. The tire chips, wood, and oil filter fluff market 

supplies are relatively stable. The tire chips derive from the Holcim/Geocycle Ada 

Oklahoma plant where they have a tire chipping plant. Geocycle hauls 25 tons in a truck, 

one way transportation is about 180 miles. Geocycle backhauls another material to Ada 

from Midlothian to decrease cost of shipping the tire chips. 

Scrap tires are chipped in Ada and transported to Midlothian because the scrap tire supply 

in Ada does not perfectly match whole tire consumption (demand) at Ada. The “safety 

valve” for surplus scrap tire supply in Ada is chipping the scrap tires and transporting the 

tire chips to Midlothian. 

Tires are not available in the open market in Oklahoma. Oklahoma runs the tire program, 

under the Oklahoma DEQ. Post consumer tires pay $1 per tire; this funds the Oklahoma 

Tire Fund. The processors, end users, and transporters of tires are all covered by the 

program, but very confusing legislation and implementation. At the end of each month 

each tire transporter and tire processor/user sends a report to state and applies to state for 

funds for tires handled. The State pays out money every month. If the program is over 

funded or under funded in a particular month, the state balances this out in dispersing the 

funds. The transporters are paid first; then the processors and end users are paid. 

Therefore, the transporters try to control the supply because they are paid first.

There are two crumb rubber operations in Oklahoma, and several cement kilns in 

Oklahoma are using tires. One company is also using tires as erosion control on 

riverbanks. Tires are therefore a stable market but also a dynamic market.

Lafarge, Seattle WA
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The Lafarge Seattle WA wet process cement plant was using chipped scrap tires as an 

alternative fuel until 2006. Prior to 2006, whole scrap tires could not be disposed of in 

MSW landfills. Therefore, suppliers chipped the tires and provided the chipped tires to 

local customers including the Lafarge cement plant. A change in local regulations in 2006 

allowed the disposal of “quartered” scrap tires in MSW landfills. Quartering and 

landfilling the scrap tires is relatively inexpensive compared to the cost of the energyintensive process to chip the scrap tires. After the change in the local regulation, suppliers 

did not have an economic incentive to continue chipping tires, and chipped tires became 

unavailable. The Lafarge plant was informed that suppliers would send not be sending the 

plant any additional shipments of chipped tires by the truck driver who brought the final 

shipment of chipped tires to the plant. The Lafarge plant decided to modify the kiln by 

installing a kiln chute so that the kiln could accept whole tires instead of chipped tires. 

The capital cost of this modification was about $4 million, not including the cost of 

permitting and performance testing. Therefore, this local regulatory change cost the 

cement plant $4 million to maintain the use of scrap tires in the cement kiln. 

The local regulatory agency, the Puget Sound Clean Air District, is responsible for air 

emissions permitting for the Lafarge Seattle plant. The objective of the kiln modification 

was to achieve 20 percent replacement of calorific value with whole scrap tires, on the 

order of 1.5 tons per hour of scrap tires. The draft permit (notice of construction) required 

a complete series of trial burn performance testing. The test program was based on a 

certain period of time with conducting 5 individual stack testing events including baseline 

and four other tests. Initially the permit modification had hard and fast dates in it for 

scheduling and conducting the performance tests. Lafarge worked with the local 

permitting agency to change these. The original dates would have made it too difficult for 

management to make decision concerning the capital expenditure. The change to a 

flexible date for the performance testing: “x days from complete installation of the 

equipment” saved the project, because management had time to make a good decision.

Washington Department of Ecology 

Solid Waste and Financial Assistance Program 

There is no statewide prohibition on landfilling of scrap tires in Washington. Municipal 

governments that operate MSW landfills control regulations on landfill disposal of scrap 

tires. Some municipal landfills accept scrap tires and quarter them for disposal. 

Washington DOE does not provide any support at the state level for scrap tire 

management. Washington cannot provide financial assistance for management of scrap 

tires and cannot collect “dollar per tire” consumer fees, because of a prohibition in 

Washington Constitution concerning the collection and distribution of such fees. The 

state can support pilot testing programs. For instance, there is some crumb rubber 

research and pilot testing work underway, and the Washington Department of 

Transportation has a “quiet road test” using rubber-modified asphalt, and the City of 

Bellevue is initiating a program to use “crumb rubber” rubberized sidewalks for tree 

plantings.

Puget Sound Clean Air Agency
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For the whole tire kiln modification project, Lafarge applied for a permit to burn whole 

tires. The local regulatory agency required performance testing because there were 

“unknowns” related to the potential effects on cement kiln emissions. For the 

performance test, there was limit on the duration of the test and the amount of scrap tires 

that could be used during the test. The performance test was conducted for 

demonstration of compliance with the cement plant MACT rule and chlorinated dioxin 

and furan emission limit. The amount of scrap tires the cement plant can burn per hour 

will be based the results of the performance test. The cement plant would be issued a 

construction approval for that amount of tires, included in the cement plant Title V 

operating permit. The cement plant needed to obtain a notice of construction because the 

cement plant needed a capital modification to convert the cement kiln to burn whole 

tires. If capital expenditure had not been required, the agency could have implemented 

the “15-day” rule under EPA MACT Rule for testing of new materials.

California Portland Cement, Colton, CA

The California Portland Cement Colton California plant is a long dry kiln that is permitted 

to use coal, petroleum coke, natural gas, fuel oil #6, fuel oil #2, and whole scrap tires. The 

scrap tire feed rate for Colton plant is at a “target” of 2 tires per revolution (i.e., two tires 

every 90 seconds) to replace approximately 50 percent of cement kiln fuel requirements. 

Petroleum coke is obtained from local refineries and also from offsite locations. The 

petroleum coke market in California is becoming more expensive, and most petroleum 

coke produced in California is therefore exported. 

The ability of the Colton plant to obtain a scrap tire permit from the South Coast Air 

Quality Management District (SCAQMD), the regional agency responsible for permitting 

for the Colton plant, is specifically related to the economics of burning scrap tires and the 

technical aspects of tire burning. The Colton plant gets paid to use the scrap tires, and 

thus gets paid to use the BTUs. Also, the use of scrap tires reduces the NOx emissions 

from the plant, and scrap tires are therefore categorized as a NOx control strategy. This 

made the permitting of scrap tires much more palatable for the agency. Scrap tires are 

now mandated in the Colton Plant air permit as a NOx control strategy for plant. 

California Portland Cement spent maybe $500,000 in air toxics emissions testing for 

“before tires” and “after tires” in order to secure the scrap tire permit from the SCAQMD. 

SCAQMD would require similar “before” and “after” air toxics testing for any other type of 

alternative fuel, so the economics of alternative fuels do not work for the plant, except for 

scrap tires.

California Integrated Waste Management Board

The California Integrated Waste Management Board (CIWMB) is responsible for 

regulation of non-hazardous wastes in California. The CIWMB estimates that close to 40 

million scrap tires per year are generated in California and approximately 10-11 million 

scrap tires are going to landfills annually in California. There are several beneficial use 

applications of scrap tires in California:

 Crumb rubber for sidewalks
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 Field turf applications, recreational surfaces, playgrounds

 Larger chips for lightweight fill for Caltrans transportation applications 

 Smaller chips for vibration attenuation for rail applications

 Construction aggregate projects

 Landfill alternative daily cover

 TDF for cement kilns/power generation

The CIWMB conducts a study of scrap tire management and generates an annual report. 

The agency does market development and studies to divert tires from landfill disposal, 

and has an annual budget of $30 million for market development efforts. Historical 

stockpiles of scrap tires in California have been largely worked off – there were two large 

tire pile fires in California in the late 1990s and early 2000s. Larger tire piles (millions of 

tires) have now been cleaned up by state agencies or by landowners, smaller tire piles still 

exist to be worked off. 

Many of the projects that the CIWMB issues grants for are transportation infrastructure 

projects conducted through local government agencies. The CIWMB issues grants to local 

agency for these types of projects. Construction aggregate projects are not developed 

enough for the CIWMB to give out grants yet; these are demonstration projects only at 

present. Tire-derived product projects are mixed local government and private entity 

projects. Grants are available for from the agency for these projects also.

Grants are no longer available from the agency for supporting the use of TDF in cement 

kilns or electric power generation. The California state legislature passed a statute that 

changed the law three or four years ago to prohibit agency grants to TDF projects. This 

was part of the public resource bill – the bill created refunding of the CIWMB tire program 

and raised the consumer scrap tire fee to $1.75 per tire. The reauthorization restricted 

grants to TDF projects. The premise of the restriction is that TDF projects don’t need to be 

subsidized. TDF as an application for scrap tires would exist even without any CIWMB 

intervention. However, a subtext here is that some legislators opposed expanding the use 

of TDF in cement kilns/power generation applications.

In California, scrap tires must be shredded or baled in order to be landfilled, but otherwise 

municipalities operating landfills set prices/practices for scrap tires to be landfilled. Scrap 

tires can also be processed into “alternative daily cover” for landfills. From an engineering 

standpoint scrap tires cannot be landfilled whole because they don’t stay in place if they 

are whole and affect the integrity of the landfill structure. 

The consumer fee for scrap tires is $1.75 per tire. Of this fee, $0.75 goes to the California 

Air Resources Board (CARB) for their diesel fuel engine research program; the rest of the 

fee goes to the CIWMB. 

Lehigh Cement, Redding, CA

The Lehigh Cement Redding California cement kiln is a dry process plant that formerly 

used chipped scrap tires; the plant then switched to whole scrap tires. The whole scrap 

tires are put into the riser duct of the four-stage preheater. In some cement plants this is 
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94

equivalent to a precalciner. The scrap tires are used to replace coal at approximately 20 

percent of fuel usage, approximately 1.75 to 2.5 tons per hour. The plant is feeding the 

maximum amount of scrap tires; increasing the feed rate would affect the pyroprocess and 

heat load and would affect product quality. There is no limit in plant operating permit on 

the scrap tire feed rate; but the plant is burning as many scrap tires as they can burn. The 

plant is permitted as a tire recycling facility. A third party on site supplies the scrap tires; 

these include truck tires and small tires as well as automobile tires. 

The Redding plant was expanded in 1982; 800,000 tons per year of cement production 

capacity. Now Redding is a “small” cement plant; tires are important to keeping the plant 

running and keeping up with competitors. 

Burning scrap tires lowers NOX emissions, and scrap tires are a cleaner fuel than coal. The 

Redding Plant has periodic stack test data; the stack test data has been provided to the 

state regulatory agency in Sacramento. Nearly half of cement plants in California are 

permitted to burn scrap tires, however only two are doing so. The California climate 

change statute AB32 could not “mandate” that cement kilns use scrap tires because some 

plants cannot burn scrap tires for technical reasons. 

The Redding Plant has experienced no community relations issues with respect to their 

use of scrap tires or with respect to other issues. The California Environmental Quality

Act (CEQA) affects scrap tire and tire-derived fuel projects and other alternative fuel 

projects such as plastics. This is because plastics fuel and scrap tires are viewed by 

regulatory agencies as “not necessarily cleaner” than coal and therefore potential 

environmental impacts need to be demonstrated. For a new alternative fuel application, it 

could take several years for the CEQA-required Environmental Impact Report (EIR) to be 

approved. Preparation of the EIR and other state permit application documents for a new 

alternative fuel application could cost $250,000 - $500,000.

The California Integrated Waste Management Board regulates scrap tire usage and also 

regulates non-hazardous solid waste landfills. The CIWMB charges $4 per tire for tire 

management. The state legislature recently passed regulations so that cement plants 

cannot apply for grants for tire-derived fuel projects anymore. In 2005, the Redding Plant 

installed an automated system for tire feed based on 2004 grant, including installing a 

sorting hopper to replace a manual sort system. Grants are no longer available to cement 

kilns for these types of projects. Grants can still go to crumb rubber and other scrap tire 

uses. Most cement plants in California also operate aggregate plants. The aggregate is 

used in asphalt plants, and crumb rubber goes to asphalt plants among other applications. 

Chipped tires can also be used in playground construction and other applications. Scrap 

tires can also be landfilled in California. 

California is a “free market” with respect to scrap tires. The Redding plant anticipates that 

despite the competition for scrap tires, scrap tires will continue to be available to the plant 

if a free market environment for scrap tires is maintained. 

CEMEX, Knoxville, TN
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The State of Tennessee has an active scrap tire management program, and the State 

Agency approached the CEMEX plant about eight years ago concerning their ability to use 

scrap tires. The plant is using about the same amount of scrap tires now as it was then. 

Scrap tires are a significant source of heat input; somewhat less than 5 percent of heat 

input to the cement kiln is scrap tires. The plant is permitted to burn three tires a minute, 

but the plant can only burn one tire a minute because of process limitations. While 

studies have been done to increase the throughput of scrap tires, capital expenditure 

would be needed to improve the rate, and no decision has been made as to whether to 

make the capital expenditure.

The scrap tires are supplied by a third party supplier. The State scrap tire management 

program gets a fee for each scrap tire and the supplier gets a fee for each scrap tire. Tire 

customers (people purchasing new tires) pay a dollar per tire to dispose of scrap tires; the 

state gets half, the supplier a gets part, and the end user gets part.

Lafarge, Tulsa, OK

The Lafarge Tulsa Oklahoma plant is a dry process plant that uses whole scrap tires. 

Approximately 12 percent of entire raw feed is tire-derived fuel. In the first quarter of 2004 

the plant used 216 tons of scrap tires. This is a relatively constant feed rate. The plant first 

started burning tires in 1994; the operating permit including scrap tires was issued in 1995. 

The permit revision incorporated scrap tires, landfill gas, and onsite generated oils and 

greases into permit [the permit conditions for landfill gas and onsite generated oils and 

greases were never used]. 

For scrap tires the permitting process was a prequalification program – i.e., the scrap tires 

are not hazardous waste and use of scrap tires would not increase emissions; the plant 

modeled ambient air concentration for SO2 and estimated the fence line concentration 

beyond the baseline. The plant does not have a Continuous Emission Monitoring System, 

so the plant is using emission factors for emissions estimation. The plant CAAA Title V 

operating permit was issued in November 2007, no criteria pollutant stack testing was 

required before that time. The plant was required to conduct opacity determination by 

May 2008; NOx and PM determination by May 2008; and a one-time test for criteria 

pollutants and HCl emissions within five years of permit issuance. This test is to be 

conducted at one set of operating conditions. No parametric testing was required for 

scrap tires vs. no scrap tires. (This differs from other states, e.g., California, in which 

parametric testing was required for cement kilns using scrap tires).

7.1.8 Automobile Shredder Residue

TXI, Midlothian, TX

TXI has been investigating use of automobile shredder residue (ASR) at their Midlothian 

plant. The material is generated by Chaparral Steel. Chaparral Steel is a former subsidiary 

of TXI that is now a separate company, and is located in Midlothian. Chaparral Steel 

generates ASR from shredding automobiles for its steel mill operation. The ASR, also 

referred to as “fluff,” includes non-metallic material from seats, dashboards, etc. ASR 

generated by automobile shredders has historically been landfilled.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

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TXI has worked with Chaparral Steel on processing ASR at the Chaparral site. The steel 

mill first processes the automobile shredder residue to separate out non-ferrous metals. 

Nickel, aluminum, copper, and other non-ferrous metals sell at prices on the order or 

$1000 per ton, so the additional material processing of the ASR to remove the non-ferrous 

metal is cost effective. Shredders use eddy current or other processes to remove the nonferrous metals to capture this value. As a final processing step, Chaparral puts the ASR 

through a “vertical mill” to get the material processed and sized to cement kiln standards. 

Chaparral processes the material down to – 1⁄4 inch size and to low moisture content. 

After this final treatment step the ASR has a calorific value similar to coal. 

The regulatory barrier to use of ASR in cement kilns is the Toxic Substances Control Act 

regulations. The TSCA regulations (referred “Superrules”) for PCB wastes affect the status 

of automobile shredder waste. Shredder waste is categorized as a “PCB waste” until proven 

otherwise, and according to TXI it is very difficult to prove otherwise. Therefore,

automobile shredders can landfill this material relatively easily, but cement kilns cannot 

burn the material without encountering major regulatory hurdles under the PCB 

regulations. TXI is continuing correspondence with EPA concerning the TSCA issue. 

7.1.9 Miscellaneous Materials

VEXOR Fuels, Medina OH / CEMEX, Wampum PA /ESSROC, Bessemer PA

Engineered Fuel (Biosolids/Plastic/Paper)

Engineering Fuel Production and Specifications

Vexor Fuels operates a facility in Medina OH that manufacturers “engineered fuel” for 

cement kilns and cogeneration plants. The engineered fuel consists of various types of 

non-hazardous materials, including used oil, wood and other biosolids, paper, and plastic. 

Vexor engineered fuel can have as much as 40 percent biomass in it, depending upon the 

alternative fuel material feedstocks used.

Vexor Fuels started processing non-hazardous materials in 2000 and by 2003 was blending 

non-hazardous fuel for cogeneration units, including Covanta and Wheelabrator facilities. 

Holcim cement contacted Vexor Fuels in 2005 concerning supplying engineered fuel to 

the Holly Hill cement plant. Vexor then purchased an existing alternative fuel processing 

facility in Dorchester SC specifically for Holly Hill supply. Holcim now owns this facility 

and Vexor Fuels is contracted as an operations consultant. The Dorchester facility 

manufactures 6,500 BTU per pound calorific value alternative fuel. The alternative fuel is 

fed into the preheater/precalciner of the Holly Hill cement kiln.

Vexor Fuels is supplying engineered fuel to cement kilns in Pennsylvania located close to 

Medina OH. These cement kilns are wet kilns without preheater/precalciners. Therefore 

the engineered fuel must be delivered into the kiln along with the coal. Engineered fuel 

therefore must have different characteristics for wet kilns than for preheater/precalciner 

kilns. 
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The CEMEX plant in Wampum PA conducted a test program using Vexor engineered fuel 

in July 2007. The “engineered fuel” looks like mulch, has a minimum calorific value of 

10,000 BTU per pound, 10 percent moisture or less, and can be conveyed into the kiln 

through a four inch pipe. The CEMEX Wampum plant test was successful, and the facility 

is now permitted by the Pennsylvania Department of Environmental Protection (PADEP) 

to use Vexor engineered fuel. Vexor Fuels indicated that they would commence delivering 

engineered fuel to the CEMEX plant in mid May 2008. Vexor Fuels anticipated a 60,000 

tons-per-year delivery contract with the Wampum plant. Vexor Fuels anticipated that the 

ESSROC cement kiln in Bessemer PA will be performance tested using for Vexor 

engineered fuel in mid-2008. The ESSROC kiln is also a wet kiln and engineered fuel 

would be delivered to the kiln along with the coal.

The cost to make engineered fuel for a wet kiln is higher than for a preheater/precalciner 

kiln, because for a wet kiln the engineered fuel has t0 meet 10,000 BTU per pound spec. 

For a preheater/precalciner kiln the spec is 6,500 BTU per pound to 8,000 BTU per pound, 

therefore Vexor Fuels can mix more wet material into the fuel; mixing this fuel is much 

easier than making fuel for wet kilns, because for wet kilns the fuel has to be like coal and 

there is only one fuel entry point into the kiln. Vexor Fuels can put inorganic material 

into the wet kiln fuel as long as they meet the 10,000 BTU per pound spec. For dry kilns

Vexor Fuels can develop both types of fuel for precalciner and for the kiln itself. The 

difference in spec is moisture content and particle size for the wet kiln fuel and the dry 

kiln fuel. The ash content is silicates and aluminates and lowers the calorific value of the 

engineered fuel, but the ash content is also raw material for the cement kiln. 

For wet kilns, any ash in the fuel goes into the clinker, so the ash content in the fuel for 

wet kilns has to be controlled. Engineered fuel cannot replace all of the coal; coal 

generates 10-12 percent ash, which goes into clinker; Vexor engineered fuel has 3 to 8 

percent ash; therefore the cement kiln would be missing some clinker production from 

burning Vexor engineered fuel rather than coal. The target for engineered fuel is 50

percent replacement of coal.

The average coal calorific value is 12,000 BTU per pound (Western PA). A 10,000 BTU per 

pound spec is established for wet kiln engineered fuel. The spec is not as high as coal 

(e.g., 12,500 BTU per pound) because making engineered fuel at this higher spec is more 

difficult, and difficult to make consistently.

One issue encountered by Vexor Fuels is that wet cement kilns could not build a separate

delivery system for this material; the existing delivery systems could not handle the

material. Vexor Fuels therefore had to develop the equipment to blow the material into 

the wet kiln right beside the coal feed; precalciner feed equipment design is much easier; 

Holcim did this modification themselves for the Holly Hill cement kiln. 

For introduction of engineered fuel with the coal, the introduction cannot change the 

flame shape because this would change the clinker production characteristics. 

Introduction of engineered fuel also cannot create gas flow backpressure in the kiln

because this would also change the flame characteristics. 

Market Characteristics
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The Vexor Fuels Medina OH facility can easily supply wet kilns because they are close to 

the facility. However, wet kilns are being phased out in favor of precalciner kilns that can 

burn 1/3 as much coal as a wet kiln does. Vexor Fuels can supply both the wet kiln and dry 

kiln markets with different spec products. However, wet kiln operators particularly want 

waste fuels to remain cost competitive with kilns that are more modern. Vexor Fuels 

worked on how to deliver a non-hazardous engineered material consistently with a narrow 

range of spec, consistent quality, and consistent supply. 

The Vexor Fuels Medina OH facility can produce sufficient engineered fuel to feed one or 

two wet kilns. Vexor Fuels plans to build additional facilities at cement kilns in Eastern 

Pennsylvania and other locations. Landfill prices are $60-$80 per ton in Eastern 

Pennsylvania and coal prices are high, but Vexor Fuels still cannot economically transport 

their engineered fuel 400 miles to cement kilns in Eastern Pennsylvania. Therefore, they 

have to build facilities in Eastern Pennsylvania to service this market. 

Raw Materials and Suppliers

Non-hazardous alternative fuel material comes from many types of facilities to the Vexor 

Fuels facility. Vexor Fuel’s customers supply this material because they want to deal with a 

“best practices” plant and avoid landfill disposal. Suppliers include petrochemicals, 

rubber, tire manufacturing scrap, pharmaceuticals, plastics, paper, food, and fragrance 

chemicals, and consumer products manufacturers. Vexor Fuels is now looking to obtain 

unrecyclable papers and plastics from MSW recyclers. This unrecyclable material has a 

high calorific value, good particle size, and other favorable qualities; but the material is 

very cheap because this material can go to landfill. Vexor Fuel’s customers are paying 

them for “complete elimination of their waste” Including elimination of the need for ash 

disposal. Cement kilns don’t generate ash. “Waste-to-Energy” facilities generate 10 -15

percent ash that still has to be landfilled. 

For precalciner kiln fuel, Vexor Fuels is incorporating aqueous waste, latex paint, epoxies, 

and related materials into the feedstock. Approximately 85 percent of materials coming 

into the Vexor Fuels facility can be blended into precalciner fuel. For wet kiln fuel, less 

aqueous material can be added to the feedstock. For both precalciner kiln fuel and wet 

kiln fuel, PVC plastics cannot be used because cement kilns have to control the feed rate 

of halogens to the kilns. 

Vexor Fuels has established direct relationships with suppliers. Some suppliers are 

contracted to supply material, while some are not contracted and the material is 

purchased on a spot basis. One issue with establishing supplier relationships is that until 

Vexor Fuels has a supply agreement it is difficult for them to establish a contract with a 

cement kiln, and vice versa. Vexor Fuels cannot simply approach DuPont and say that 

Vexor Fuels will dispose of all their byproduct materials unless they first have a contract 

with a cement kiln.

Vexor Fuels is not overly concerned with volume of supply of feedstock for engineered 

fuels because they understand the alternative fuel materials business and markets. Some 
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streams are priced high because generator can’t easily manage them; other streams are 

priced low because they can go to landfills.

Vexor Fuels indicated that markets for alternative fuel materials (feedstock) and 

engineered fuel product vary by region. For example, South Florida does not have 

industrial base to generate plastics; but South Florida does have lots of MSW. MSW is 

cheap, but coal costs $80 per ton in Miami, so the supply and demand costs for engineered 

fuel balance out to some extent. Vexor Fuels is competing with low landfill costs and 

relatively low coal costs in some areas. Coal is $40 per ton in western PA; Coal is $80 per 

ton in southern CA.

Every material that comes into the Medina OH facility is “preapproved” by Vexor Fuels; 

there are standard approval procedures and an Ohio EPA-approved Waste Analysis Plan

(WAP); each waste is given a unique Waste Approval Number. Shipments are subject to 

100 percent QA/QC using fingerprint analysis on every container to ensure that the 

material shipped is what the generator identified and what the WAP approved; generators 

are notified within 24 hours of any discrepancies and the material must then be removed 

from the site within 10 days; these procedures ensure that Vexor Fuels does not 

inadvertently process hazardous waste.

Regulatory Barriers

Vexor Fuels has encountered regulatory barriers mainly at state level, and indirectly with 

EPA through implementation of the CAAA Title V Program. One issue is that Vexor Fuels 

is blending feedstocks to make a specification-driven engineered fuel product. Therefore,

Vexor Fuels is unique operation. The quality of the engineered product supplied to the 

cement kiln is not going to vary regardless of the specific alternative fuel materials used to 

produce it; the calorific value, particle size, and carbon hydrogen nitrogen ratios are all 

controlled product specifications. One regulatory agency from which Vexor Fuels was 

seeking a permit (to supply a lime kiln) did not clearly understand at first that the 

engineered fuel product spec doesn’t vary regardless of the variability of the specific 

feedstocks used to make the material.

Vexor Fuels also identified an issue that there are different testing protocols for different 

kilns in different regions; a uniform testing program would help to allow testing first and 

then allow modeling for new permits after a certain number of tests were conducted; at 

present Vexor Fuels has to test each kiln every time a new alternative fuel is introduced; 

stack testing is expensive for cement kilns. In recent performance testing for Vexor Fuels, 

stack testing has shown either no increases in emissions or increases below action levels 

and Title V operating permit thresholds. The cost of testing is $30,000 to $100,000 per 

stack test per kiln, and despite the consistent results, each kiln has to be tested before 

engineered fuel can be introduced. 

Vexor Fuels also identified as an issue at the municipal and local government level 

concerning the definition of “solid waste” and what gets paid for. The “unrecyclable” 

material generated by MSW authorities is classified as “waste.” If the state regulatory 

agency requires “solid waste fees” and “solid waste facility permits” for facilities that are 

handling this unrecyclable material, the material may not be able to be used for recycling. 
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South Carolina was very proactive on this issue. The Vexor Fuels facility in South Carolina 

did not need to be regulated as a “solid waste facility;” South Carolina regulations are that 

if 75 percent of the solid waste material is “recycled” including used as a fuel, the facility is 

exempt from state solid waste regulations. 

Lafarge, Seattle, WA

Biodiesel

The Lafarge Seattle plant permit process does not prevent the plant from using alternative 

fuels and raw materials; the plant is investigating some new opportunities such as 

biofuels. If state agencies determine that a material is a “waste,” then cement kilns are 

capped as to the number of tons per day they can use. There is no corresponding cap on 

use of materials that are “fuels.” Glycerin generated from biodiesel plants, for example, 

has a high calorific value, but the mid-level state environmental agency staff want to 

classify this material as a “waste” rather than as a fuel. If the plant was designed as a 

biodiesel plant, it is uncertain whether the glycerin produced by the plant a “byproduct” 

or a “waste.” 

Used Oil

The Lafarge Seattle plant uses “used oil” including tank bottoms oil and used motor oil, 

and other types of non-hazardous oils. This material comes from intermediate sources; a 

supply contractor brings in loads in range of 4000 gallons, two to three truckloads per 

week. The Lafarge Seattle plant reported that the used oil market is dynamic and that 

there is competition for used oil. Because of rising energy costs, pricing of used oil is 

starting to rival coal and petroleum coke in some places, and other industries are 

competing for the used oil, specifically the asphalt industry.

California Portland Cement, Colton, CA

Latex Paint Solids

The California Portland Cement Colton plant uses processed latex paint solids as a raw 

material. This material is obtained from paint recycling company that conducts 

household paint waste collection. Household recycling of non-hazardous waste is 

common in California. This material does not include oil-based paint, only latex paint. 

The recycling company separates the latex paint solids from the paint waste and resells 

the liquids as “graffiti removal paint.” California Portland Cement adds CKD to the latex 

paint solids, and then the CKD/latex paint solids mixture is fed into kiln. The latex paint 

solids are “sticky” and aggregate the CKD; this allows recycling of more CKD into the kiln. 

The methylcellulose content of latex paint is made into a grinding agent and plasticizing 

agent for cement. 

Holcim/Geocycle, Midlothian, TX

Oil Filter Fluff
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The Holcim Midlothian plant has been using oil filter fluff as an alternative fuel for the 

past ten years. Oil filter fluff is generated from used vehicle motor oil filters after the free 

oil and the metal parts are removed. The remaining oil-soaked paper is used as an 

alternative fuel. The oil filters are generated by automobile service centers in the Dallas 

and Houston metropolitan areas. The oil filter fluff market is relatively stable and the 

plant does not have any supply issues

Holcim/Geocycle, Devil’s Slide, UT

Scrap Carpet

Geocycle is responsible for supplying alternative fuels and raw materials to Holcim cement 

plants in Utah, Montana, and Colorado, including the Utah Devil’s Slide plant. None of 

the Holcim Mountain State plants are permitted to accept hazardous waste. Geocycle 

operations receives alternative fuel materials and conducts preprocessing / blending 

operations to prepare “engineered fuel.” Geocycle delivers “engineered fuel” to the Devil’s 

Slide cement kiln.

The Devil’s Slide plant is more than 100 years old; updated in 1998 to dry process plant. 

Alternative fuels and raw materials are used at the Utah plant: scrap tire chips and diaper 

scrap (cubed) have been used for about 15 years. The new dry process plant was designed 

to accommodate these alternative fuels. The Utah operation also uses plastics and scrap 

from mattress companies, including fluff, foam, fabric, etc. after wood and metal (frames) 

are removed. The fuel mix for the Utah plant is approximately: 

 15,000 tons of tire chips per year

 6,000 tons of plastics per year

 2,000 tons of textiles and carpet per year

This constitutes approximately 30 percent of the heat input into the kiln. Geocycle / 

Holcim has a goal to increase this number. Utah was at 20-25 percent for years before 

Geocycle started adding new alternative fuels. Holcim recently invested 2 million dollars 

for installing another feeding point at the Utah kiln. Holcim could install a second 

additional feeding point to feed wood or some other type of material if the material is 

available. 

Geocycle processes scrap carpet into alternative fuel. Geocycle first analyzes the scrap 

carpet to create a “profile” both for the purposes of material management and process 

control/cement clinker quality control. Geocycle then shreds the material and sends it to 

the Utah cement plant.

Geocycle receives carpet pad/cutting scrap, e.g., from regional carpet supplier RC Willey 

and Company. This includes old carpet pads, cutting scraps, rolls, etc. from residential 

and commercial carpet replacement. Geocycle preprocesses the scrap carpet to remove 

metal strips, nails, wood, etc. from the carpet prior to processing. Scrap carpet has 12,000 

– 15,000 BTU per pound. Geocycle is working with CARE, a national carpet recycling 

organization, on carper recycling issues. 
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Geocycle has found it difficult to find suppliers for scrap carpet; small carpet installers 

cannot manage consistent production of quality scrap carpet material because it is 

difficult to control the practices of their installers. The installers need to separate the 

scrap carpet from other debris generated from the installation job. This segregation of 

material involves time and cost, and the need for separate transportation of the scrap 

carpet from the installation site to the cement kiln also involves time and cost. Large 

carpet companies can coordinate better because they send out carpet installers from 

central location.

Geocycle takes whatever scrap carpet installers bring them at the moment, approximately 

2,000 tons of textiles and scrap carpet per year. Geocycle can use different types of scrap 

carpet, but Geocycle cannot accept “trash” that is mixed with scrap carpet. The customer 

(e.g., carpet installers) pays Geocycle for taking the scrap carpet material for material 

disposal, as opposed to paying a local landfill a tipping fee for material disposal. CARE is 

waiting to see if Geocycle can make relationships with “big companies” and work out 

issues with processing and transportation of the material. 

The cost of transportation of scrap carpet is an issue: the hauling capacity of a truck may 

be only three to five tons of carpet, as opposed to a truck hauling capacity of 20 - 25 tons 

of tire chips. Landfill cost involves tipping fee and transportation, and scrap carpet takes 

up a lot of space in landfills because it is loose. Therefore, there is a cost for landfilling 

this material.

Geocycle’s price for services takes into account transportation distance to the cement 

kilns. Geocycle is targeting customers close to Geocycle, e.g., within a 50 mile radius of 

the cement kiln. Geocycle’s major “competitor” for waste carpet is the relatively low cost 

of landfill disposal in Utah. If there is a landfill close to the carpet installation site, the 

carpet installer would ordinarily send the material there. Therefore, Geocycle deals with 

corporate sustainability goals, etc., and sells a “value added” service to divert scrap carpet 

and other materials away from landfills. . 

Geocycle has service agreements with customers, some are multi-year, and some are for a 

specific event, such as a ski resort changing their carpet. Service agreements with 

individual companies may have an estimated tonnage per month and quality specification, 

e.g., waste volume not to exceed 20,000 pounds per year. 

The Devil’s Slide plant has a CAAA Title V operating permit that lists the conventional 

and alternative fuels that the plant can accept individually. Conventional fuels, such as 

TDF or diaper scrap, are separately listed in the permit. The permit has various 

specifications, such as maximum percent sulfur in coal and specifications on used oil. Up 

to 15 percent “coal additives” can be added under the permit. Holcim can request addition 

of additional alternative fuels to permit, working under the “15 percent” threshold limit. 

For introduction of a new alternative fuel, Holcim submits “ultimate/proximate” analysis 

of fuel to the state regulatory agency. Geocycle does a more detailed analysis of the 

material beyond an “ultimate/proximate” analysis because of process control reasons. So 

far, no stack tests have been needed to introduce new fuels under the Title V operating 

permit limits for emissions of criteria pollutants, PM, SO2, NOx, etc.
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Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

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8. Appendix B: Study Contacts 

Company City State

Ash Grove Cement Foreman AR

Ash Grove Cement 

Overland 

Park

KS

California Portland Cement Glendora CA

CEMEX Knoxville TN

GRR: Giant Resource Recovery Harleyville SC

Lafarge Seattle WA

Lafarge Sugar Creek MO

Lafarge Tulsa OK

Lafarge Tulsa OK

Lehigh Cement Company Fleetwood PA

Lehigh Cement Company Allentown PA

Lehigh Cement Company Glens Falls NY

Lehigh Cement Company Redding CA

Texas Industries Midlothian TX

Holcim Morgan UT

Geocycle (Holcim) Devil’s Slide UT

Geocycle (Holcim) Midlothian TX

Geocycle (Holcim) Dundee MI

Supplier and Other Contacts City State

Exxon Mobil Baytown TX

Shell Houston TX

Marathon Oil Houston TX

Vexor Fuels Medina OH
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

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Regulatory Agency Contacts

Agency City State

Texas Commission on 

Environmental Quality (TCEQ) Austin TX

Shasta Air Quality District Redding CA

Missouri Department of Natural 

Resources (MoDNR) Columbia MO

California Integrated Waste 

Management Board (CA IWMB) Sacramento CA

California Integrated Waste 

Management Board (CA IWMB) Sacramento CA

Pennsylvania Department of 

Environmental Protection 

(PADEP) South Central District

Reading PA

Puget Sound Clean Air Agency Seattle WA

Washington Department of 

Ecology (WDOE) Solid 

Waste/Financial Assistance

Lacey WA

Texas Commission on 

Environmental Quality (TCEQ) Austin TX

Texas Commission on 

Environmental Quality (TCEQ) Austin TX

Texas Commission on 

Environmental Quality (TCEQ) Austin TX

Pennsylvania Department of 

Environmental Protection 

(PADEP) Northwest District

Meadville PA

South Carolina Department of 

Health and Environmental 

Conservation (SCDHEC)

Columbia SC

South Carolina Department of 

Health and Environmental 

Conservation (SCDHEC)

Columbia SC

California Department of Toxic 

Substance Control (CA DTSC) Sacramento CA
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9. Appendix C: Kiln Types

9.1 Wet Process

The wet process is so named because the proportioned raw materials mixed with water 

and fed into the kiln in the form of a slurry. The amount of water varies depending on the 

physical and chemical properties of the raw materials, and the raw meal typically contains 

30 to 40 percent moisture.210 Wet grinding of hard minerals is usually much more efficient 

than dry grinding, and wet processing might be preferable when raw materials contain 

high moisture content.

The kiln is generally larger in plants using the wet process because the water is first 

evaporated in the lower temperature zone. The length to diameter ratio may be up to 38, 

with lengths up to 252 yards.211 Also, more fuel is needed to create sufficient energy to 

evaporate the water. Fuel use in a wet kiln can vary between 4.6 and 6.1 MBtu per ton 

clinker.212 The capacity of large units may be up to 3,970 short tons of clinker per day.213

9.2 Long Dry Process

In dry processing, the materials are ground into a flowable powder in horizontal ball mills 

or in vertical roller mills. The feed material has about 0.5 percent moisture content and is 

pneumatically or mechanically conveyed to the upper end of the kiln. Two types of dry 

process plants predominate: (1) preheater and precalciner kilns (discussed below) and (2) 

long dry kilns.

Dry process kilns operate with a high exit gas temperature of approximately 449° C and 

typically employ water sprays to cool the gas before it enters the dust control equipment. 

The fast-flowing combustion gases tend to blow the powdery raw meal out from the kiln.

Cyclones are used to collect cement kiln dust (blown out by the heat of the kiln) from the 

exhaust gas in order to facilitate the return of the particulate back to the kiln. Additional 

dust is collected as the exhaust gas enters a baghouse. The CKD collected is then fed back 

into the kiln, recycled in other processes, or disposed.

9.3 Variations of the Dry Process

Preheaters and precalciners are modifications of the dry process. With these processes, 

operators preheat and calcine the raw meal before it enters the kiln – using some heat that 

escapes from the kiln, which reduces the energy demands of the pyroprocess.

The preheater and precalciner process kilns have only calcining and clinkering zones, 

because the material has been dried before entering the kiln. Accordingly, these kiln 

types may in some cases be very short (under 61 meters).214 The wet process was initially 

used to improve the chemical uniformity of raw materials being processed; however, it 

requires 47 percent more energy per ton of clinker production than the average for dry 

processes.215 Technological improvements have allowed cement makers to utilize the dry 

process without quality deficiencies, and no new wet kilns have been built in the United 

States since 1975.216 Some plants are switching from the wet to the dry process.217 About 80

percent of U.S. cement production capacity now relies on the dry process technology.218
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9.4 Dry Process with Gas-Suspension Preheaters:

Suspension preheater kilns preheat and partially calcine raw meal by passing it through a 

system of heat exchange cyclones before it enters the kiln. In traditional dry process kilns, 

the intense heat causes dust-laden gas to escape the kiln. To collect the escaping dust, 

operators used “cyclones.” The cyclone is conical vessel into which a dust-bearing gasstream passes tangentially, producing a vortex within the vessel. The solids are thrown to 

the outside edge of the vessel by centrifugal action, and leave through a valve in the vertex 

of the cone.

Because of the heat associated with the escaping gas, operators can send the raw materials 

through the cyclone, resulting in a heat exchange. The gas is cooled, producing less waste 

of heat to the atmosphere, and the raw materials are heated. 

Fans draw the gases through the string of cyclones. The number of cyclones stages used 

in practice varies from 1 to 6. Generally, the cost of powering the fans outweighs the 

benefits when more than 6 cyclones are used. Typical fuel consumption of a dry kiln with 

4 or 5 stage preheating can vary between 2.7 and 3.0 MBtu per ton of clinker, and the most 

efficient preheater, precalciner kilns use approximately 2.5 MBtu per ton clinker.219

A disadvantage of the preheater kiln is that plug-up problems can occur at he lower 

cyclone stage and the kiln inlet due to high concentrations of volatile constituents such as 

alkalis, sulfur, and chlorides in the kiln exit gases. To mitigate this problem, alkali and 

sulfur bypass systems allow evacuation of some of the kiln exit gases before they reach the 

preheater cyclones.

9.5 Precalciner Kilns

Precalciner technology involves a second combustion chamber added between the kiln 

and a conventional pre-heater, allowing for further reduction of the kiln fuel 

requirements. Precalciner systems associated with kilns with tertiary air ducts are supplied 

with air from the exhaust gases from the clinker cooler. Precalciner kilns without tertiary 

air ducts receive air that passes through the kiln itself. 

Precalciners using the hot air from the kiln use that air to ignite fuel in a combustion 

chamber at the base of the preheater. Less expensive, lower grade fuels such as sub 

bituminous coal, lignite, and oil shale, as well as tires and waste oil, can be burned in the 

auxiliary firing unit, reducing fuel cost per unit of clinker. 

The hot combustion air for precalciners with tertiary air ducts arrives in a duct directly 

from the cooler, bypassing the kiln. The feed entering the rotary kiln is 92-98 percent

calcined (100 percent calcined meal would be sticky and cause feed pipe plugs), so the kiln 

has only to raise the feed to sintering temperature. An advantage of this type of 

precalciner is that a large proportion of the alkali-laden kiln exhaust gas can be taken off 

as alkali bleed. Because this accounts for only 40 percent of the system heat input, it can 

be done with lower heat wastage than in a simple suspension preheater bleed.
Figure 5 Preheater Unit 

Source: California Environmental Protection Agency, Compliance Assistance Program, Cement Kilns, October 1996, excerpted from Figure 300.5 

Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

108
Figure 6. Basic Workflow with Preheater unit 

California Environmental Protection Agency, Compliance Assistance Program, Cement Kilns, October 1996, excerpted from Figure 200.4 

Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials 

109
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

110

 

1 U.S. and Canadian Labor-Energy Input Survey 2006, Portland Cement Association and Economic 

Research, December 31, 2006.

2 U.S. Geological Survey Mineral Yearbook: Cement, 2006.

3

EU Directive 94/67/EC, http://rod.eionet.europa.eu/show.jsv?id=508&mode=S; WBCSD, 

“Guidelines for the Selection and Use of Fuels and Raw Materials in the Cement Manufacturing 

Process Cement Sustainability Initiative,” http://www.wbcsdcement.org/pdf/tf2/tf2_guidelines.pdf.

4 Holcim: “Guidelines on Co-processing Waste Materials in Cement Production,” pg. 7, 2006.

5

EPA Office of Solid Waste and Emergency Response: Environmental Fact Sheet

Final Standards Promulgated for Petroleum Refining Waste, EPA530-F-98-014, July 1998.

http://epa.gov/osw/hazard/wastetypes/wasteid/petroleum/petrofs6.pdf

6

CEMBUREAU, Alternative Fuels in Cement Manufacture – Technical and Environmental Review, p. 

3, 1997.

7USGS, 2005 Minerals Yearbook, February 2007, p. 16.2. 

http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmyb05.pdf. The 10 largest 

companies in 2005 were Holcim (US) Inc.; Lafarge North America, Inc.; CEMEX, Inc.; Buzzi Unicem 

USA, Inc.; Lehigh Cement Co.; Ash Grove Cement Co.; Essroc Cement Corp.; Texas Industries Inc.; 

California Portland Cement Co.; and St. Mary’s Cement, Inc.

8 USGS, Mineral Commodity Summaries – Cement, January 2008, 

http://minerals.usgs.gov/minerals/pubs/commodity/cement/mcs-2008-cemen.pdf. 

9 U.S. Geological Survey Mineral Commodity Summary, Cement, 2008 

http://minerals.usgs.gov/minerals/pubs/commodity/cement/mcs-2008-cemen.pdf

10 Lawrence Berkeley National Laboratory, Energy Efficiency Improvement Opportunities for 

Cement Making, January 2004.

11 USGS Mineral Yearbook: Cement (USGS 1993 through 2006)

12 Murray, A.E., and Price, L., 2008. Use of Alternative Fuels in Cement Manufacture, Ashley 

Murray, Energy and Resources Group, UC Berkeley, Lynn Price Energy Analysis Department

Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, May 2008

13 U.S. and Canadian Labor-Energy Input Survey 2006, Portland Cement Association and Economic 

Research, December 31, 2006.

14 U.S. Geological Survey Mineral Yearbook: Cement, 2006.

15 Holcim: “Guidelines on Co-processing Waste Materials in Cement Production,” pg. 7, 2006.

16 EPA Office of Solid Waste and Emergency Response: Environmental Fact Sheet

Final Standards Promulgated for Petroleum Refining Waste, EPA530-F-98-014, July 1998.

http://epa.gov/osw/hazard/wastetypes/wasteid/petroleum/petrofs6.pdf

17 Beneficial Use of Industrial By-Products in Cement Kilns: Analysis of Utilization Trends and 

Regulatory Requirements, Prepared under EPA Contract No. 68-W-03-028, Work Assignment 2-13, 

Draft Report, April 21, 2005

18 SSD, Beneficial reuse of Industrial Byproducts in the Gulf Coast Region, February 2008, 

www.epa.gov/ispd/pdf/beneficial-reuse-report.pdf.

19 SSD, Beneficial reuse of Industrial Byproducts in the Gulf Coast Region, February 2008, 

www.epa.gov/ispd/pdf/beneficial-reuse-report.pdf.

20 See FIRST website, accessed at: 

http://www.foundryrecycling.org/Home/WhatisRecycledFoundrySand/tabid/294/Default.aspx.

21 Alicia Oman, American Foundry Society (AFS), personal communication, 12/21/07, and, Foundry 

Industry Benchmarking Survey, August 2007, accessed at: 

http://www.strategicgoals.org/benchmarking/foundryresults8-7.pdf. 

22 U.S. Geological Survey, 2006 Minerals Yearbook, Slag – Iron and Steel, 

http://minerals.usgs.gov/minerals/pubs/commodity/iron_&_steel_slag/myb1-2006-fesla.pdf

23 U.S. Geological Survey. Minerals Yearbook, Cement: 1999, 2000, 2001, 2002, 2003, 2004, 2005. 

http://minerals.usgs.gov/minerals/pubs/commodity/cement/
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

111

 

24 Robert H. Falk and David B. McKeever, “Recovering wood for reuse and recycling A United States 

Perspective,” Management of Recovered Wood Recycling, Bioenergy, and other Options, ed. 

Christos Gallis (Thessaloniki: University Studio Press, 2004) 29-40.

25 Holcim/Geocycle, Theodore, AL

26 Holcim/Geocycle, Midlothian TX

27 ExxonMobil; Shell

28 ExxonMobil

29 ExxonMobil; Shell

30 Communication, Tom Purcell, API, to Kevin Easley and Carl Koch, EPA; 9/8/2008, “Additional 

comments on Cement Sector Document;” attached file, 

“CementSectorReportDataReview5Sep08.doc;” containing memo developed by Mary Catherine Fish 

and Nick Bauer, MCF Consulting.

31 Communication, Tom Purcell, API, to Kevin Easley and Carl Koch, EPA; 9/8/2008, “Additional 

comments on Cement Sector Document;” attached file, 

“CementSectorReportDataReview5Sep08.doc;” containing memo developed by Mary Catherine Fish 

and Nick Bauer, MCF Consulting.

32 Lafarge, Seattle WA; Lehigh Cement, Redding, CA; California Portland Cement, Colton CA; 

Lehigh Cement, Fleetwood PA

33

 U.S. and Canadian Labor-Energy Input Survey 2006, Portland Cement Association and Economic 

Research, December 31, 2006.

34 United States Geological Survey. Minerals Yearbook, Cement: 1994 

http://minerals.usgs.gov/minerals/pubs/commodity/cement/170494.pdf (accessed on October 19, 

2007); and United States Geological Survey. Minerals Yearbook, Cement: 2004 

http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmyb04.pdf (accessed on 

October 19, 2007)

35 American Coal Ash Association (ACAA), CCP Production & Use Surveys (2001 through 2005)

http://www.acaa-usa.org/CCPSurveyShort.htm (accessed on October 19, 2007)

36

 Portland Cement Association, 2006 U.S. and Canadian Portland Cement Industry: Plant 

Information Summary, http://www.cement.org/smreport07/sec_page2_1.htm (accessed on October 

19, 2007)

37 American Coal Ash Association, Coal Combustion Products Production and Use Survey; See press 

release at http://acaa.affiniscape.com/associations/8003/files/2006_CCP_Survey_(Final-8-24-

07).pdf.

38 United States Geological Survey. Minerals Yearbook, Cement: 2005, Table 6, (calculation of coal 

combustion products includes fly ash, other ash, and other slags).

39 Rubber Manufacturers Association, Scrap Tire Markets in the United States, 2005, p.6; 

https://www.rma.org/publications/market_information/index.cfm?PublicationID=11453&CFID=188

42373&CFTOKEN=17873005

40 United States Geological Survey. Minerals Yearbook, Cement: 2005 

http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmyb05.pdf (accessed on April 

2, 2008)

41 Id.

42 Rubber Manufacturers Association: Scrap Tire Markets in the United States 2005 Edition, 

November 2006, Page 93, as cited in: Murray, A.E., and Price, L., 2008. Use of Alternative Fuels in 

Cement Manufacture, Ashley Murray, Energy and Resources Group, University of California, 

Berkeley; Lynn Price, Energy Analysis Department, Environmental Energy Technologies Division, 

Lawrence Berkeley National Laboratory, 2008, Page 23.

43 Corti, A. and L. Lombardi, 2004. "End life tyres: Alternative final disposal processes compared by 

LCA." Energy 29(12-15): 2089-2108, as cited in: Murray, A.E., and Price, L., 2008. Use of Alternative 

Fuels in Cement Manufacture, Ashley Murray, Energy and Resources Group, University of 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

112

 

California, Berkeley; Lynn Price, Energy Analysis Department, Environmental Energy Technologies 

Division, Lawrence Berkeley National Laboratory, 2008, Page 23.

44 Rubber Manufacturers Association: Scrap Tire Markets in the United States, 2005 Edition 

November 2006.

45 Rubber Manufacturers Association: Scrap Tire Markets in the United States, 2005 Edition 

November 2006.

46 Rubber Manufacturers Association, “Energy Recovery from Scrap Tires,” press release, July 2007. 

47 http://www.ciwmb.ca.gov/Organics/Biosolids/ (accessed April 4, 2008)

48 North East Biosolids and Residuals Association, A National Biosolids Regulation, Quality, End Use 

& Disposal Survey, 2007.

49 EPA Municipal and Industrial Solid Waste Division, Biosolids Generation, Use, and Disposal in the 

United States, September 1999, page 49.

50 Lafarge/Systech, Sugar Creek, MO

51 TXI, Midlothian, TX; Lehigh Cement, several plants

52 EPA, Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and 

Figures for 2006, p. 5.

53 Lehigh Cement, York, PA, Redding, CA; Lafarge/Systech, Sugar Creek, MO

54 Argonne National Laboratory, 2003.

55 Kent Kiser, Editor of Scrap Magazine: personal communication with Jonathan Kiser, ICF 

International, April 3. 2008

56 Steel Recycling Institute (SRI) Fact Sheet, 2006 Steel Recycling Rates. http://www.recyclesteel.org/PDFs/2006Graphs.pdf (accessed on April 3, 2008)

57 TXI, Midlothian, TX

58 Evaluation of Shredder Residue as Cement Manufacturing Feedstock March 2006 CA Department 

of Toxic Substances Control 

http://www.dtsc.ca.gov/TechnologyDevelopment/upload/auto_shredder_report.pdf

59 Argonne National Laboratory: Green Technologies Fact Sheet – Recycling Automotive Scrap, June 

2007. http://www.transportation.anl.gov/pdfs/R/253.pdf (accessed on April 4, 2008)

60 http://www.transportation.anl.gov/features/asr.html

61Recycling: Salyp Solutions For WEEE & ELV Recycling: http://www.salyp.com/ (accessed on April 

4, 2008)

62 Boughton, B., Horvath, A. (2006). "Environmental assessment of shredder residue management." 

Resources, Conservation and Recycling 47: 1-25, as cited in: Murray, A.E., and Price, L., 2008. Use of 

Alternative Fuels in Cement Manufacture, Ashley Murray, Energy and Resources Group, University 

of California, Berkeley; Lynn Price, Energy Analysis Department, Environmental Energy 

Technologies Division, Lawrence Berkeley National Laboratory, 2008, Page 28, Page 29. 

63 Holcim/GeoCycle, Devil’s Slide UT, Midlothian TX

64 http://www.carpetrecovery.org/annual.php, Figure 5, Page 21.

65 http://www.carpetrecovery.org/annual.php, Figure 2, Page 17.

66 Realff, M., Lemieux, P., Lucero, S., Mulholland, J., Smith P., 2005. Characterization of transient 

puff emissions from the burning of carpet waste charges in a rotary kiln combustor. Cement 

Industry Technical Conference, 2005. Conference Record, as cited in: Murray, A.E., and Price, L., 

2008. Use of Alternative Fuels in Cement Manufacture, Ashley Murray, Energy and Resources 

Group, University of California, Berkeley; Lynn Price, Energy Analysis Department, Environmental 

Energy Technologies Division, Lawrence Berkeley National Laboratory, 2008, Page 23.

67 Holcim/GeoCycle, Devil’s Slide UT.

68 Realff, M., Lemieux, P., Lucero, S., Mulholland, J., Smith P., 2005. Characterization of transient 

puff emissions from the burning of carpet waste charges in a rotary kiln combustor. Cement 

Industry Technical Conference, 2005. Conference Record, as cited in: Murray, A.E., and Price, L., 

2008. Use of Alternative Fuels in Cement Manufacture, Ashley Murray, Energy and Resources 
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

113

 

Group, University of California, Berkeley; Lynn Price, Energy Analysis Department, Environmental 

Energy Technologies Division, Lawrence Berkeley National Laboratory, 2008, Page 26, Page 27.

69 California Portland Cement, Colton CA

70 Lafarge, Seattle WA

71 Lehigh Cement, Redding CA

72 Lehigh Cement, Corporate HQ

73 California Portland Cement, Colton CA

74 Vexor Fuels, Medina OH

75 Lehigh Cement

76 CEMEX

77 Lafarge, Seattle WA; Lehigh Cement, Redding CA

78 Lafarge, Seattle WA

79 Lehigh Cement, Redding CA

80 Vexor Fuels, Medina OH

81 California Portland Cement Company, Colton CA

82 Vexor Fuels, Medina OH

83 Vexor Fuels, Medina OH

84 Holcim/Geocycle, Devil’s Slide, UT

85 Lafarge/Systech, Sugar Creek, MO

86 Lehigh Cement, Redding CA

87 TXI, Midlothian, TX

88 Holcim/Geocycle, Midlothian TX

89 Puget Sound Clean Air Agency WA.

90 South Carolina Department of Health and Environmental Control (SCDHEC)

91 Shasta County Air Quality District

92 Shell, ExxonMobil

93 Marathon Oil

94 ExxonMobil; Shell

95 TCEQ

96 Rubber Manufacturers Association: Scrap Tire Markets in the United States, 2005 Edition 

November 2006, Page 83.

97 SCDHEC

98 SCDHEC

99 Personal communication between Ms. Erika Guerra, Holcim and Mr. Robert Lanza, ICF 

International, August 13, 2008, 1:00 PM.

100 Washington, California

101 Puget Sound Clean Air Agency

102 Vexor Fuels, Medina OH

103 CEMEX, Victorville CA

104 TXI, Midlothian TX

105 http://ecfr.gpoaccess.gov/cgi/t/text/textidx?c=ecfr&sid=7ac7957d31405806e269b992d0a3abaa&rgn=div8&view=text&node=40:30.0.1.1.17.4.1.

4&idno=40

106 Personal communication with Tom Tyler, EPA [email to Robert Lanza, April 15, 2008]

107 Evaluation of Shredder Residue as Cement Manufacturing Feedstock March 2006 CA 

Department of Toxic Substances Control 

http://www.dtsc.ca.gov/TechnologyDevelopment/upload/auto_shredder_report.pdf Page 2.

108

 Lafarge/Systech; Holcim/Energis (now Holcim/GeoCycle); Giant Cement/Giant Resource 

Recovery

109 Cadence Environmental

110 Lehigh Cement, Fleetwood, PA
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

114

 

111 CEMEX, Knoxville TN

112 Lafarge/Systech, Sugar Creek MO

113 Lehigh Cement, York PA

114 Vexor Fuels, Medina OH

115 Holcim, Trident, MT

116 Holcim, Artesia MS; Giant Cement, Harleyville SC

117 For further information on trends in fuel use, see PCA, U.S. and Canadian Labor-Energy Input 

Survey 2006,

118 Holcim/GeoCycle, Midlothian TX

119 Lafarge/Systech, Sugar Creek, MO

120 Lehigh Cement, Fleetwood PA; Lehigh Cement, Redding CA

121 Ash Grove Cement, Foreman AR/Chanute KS; Giant Resource Recovery, Harleyville SC

122 Shell, ExxonMobil

123 Lehigh Cement, Fleetwood PA; CEMEX, Knoxville TN

124 Holcim/Geocycle, Midlothian TX; Ada OK

125 Lehigh Cement, Fleetwood PA; California Portland Cement, Colton CA; Lehigh Cement, Union 

Bridge, MD

126 TXI, Midlothian TX

127 CEMEX, Victorville, CA

128 Vexor Fuels; Synagro

129 Synagro; Vexor Fuels 

130 Lafarge/Systech, Sugar Creek, MO; Lehigh Cement, York PA; TXI, New Braunfels TX

131 Lafarge/Systech, Sugar Creek, MO

132 Holcim/Geocycle, Holly Hill SC; Artesia MS

133 Holcim/GeoCycle, Devil’s Slide UT

134 Holcim/GeoCycle, Holly Hill SC; Midlothian TX

135 Holcim/GeoCycle, Theodore, AL.

136 Lehigh Redding CA.

137 Lehigh Fleetwood PA.

138 ExxonMobil.

139 Lafarge, Fredonia KS.

140 ExxonMobil.

141 Shell, ExxonMobil.

142 Marathon Oil, Houston TX.

143 Rubber Manufacturers Association, “Energy Recovery from Scrap Tires,” press release, July 2007.

144 TXI, Midlothian TX.

145 Lehigh Cement, Fleetwood PA.

146 CEMEX, Knoxville TN.

147 CEMEX, Knoxville TN.

148 Lafarge, Tulsa OK.

149 Washington Department of Ecology, California Integrated Waste Management Board.

150 U.S. Environmental Protection Agency: Management of Scrap Tires – Ground Rubber 

Applications. http://www.epa.gov/garbage/tires/ground.htm (accessed on March 31, 2008)

151 Rubber Manufacturers Association: Page 16, Figure 2: 2005 U.S. Scrap Tire Disposition

152 The California Integrated Waste Management Board reported that approximately 1o million tires 

are landfilled in California annually.

153 Washington.

154 Lafarge, Sugar Creek, MO.

155 California Portland Cement, Colton CA; Lehigh Cement, Redding, CA.

156 Including Montana

157 California Portland Cement, Colton CA
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

115

 

158 Lehigh Cement, Redding CA

159 CEMEX, Victorville CA; Vexor Fuels.

160 Lehigh Cement, Union Bridge MD; CEMEX, Victorville CA; Vexor Fuels

161 The Lehigh Cement Union Bridge MD cement kiln is now using biosolids; the CEMEX Victorville 

CA performance test was also reported to be successful.

162, PADEP; Lehigh Cement; TXI, Midlothian TX.

163 PADEP; Lehigh Cement.

164 TXI, Midlothian TX.

165 Lafarge/Systech, Sugar Creek OK.

166 Evaluation of Shredder Residue as Cement Manufacturing Feedstock March 2006 CA 

Department of Toxic Substances Control 

http://www.dtsc.ca.gov/TechnologyDevelopment/upload/auto_shredder_report.pdf

167 Final Rule To Reduce Air Toxics Emissions From Area Source Electric Arc Furnace Steelmaking 

Facilities: EPA Fact Sheet http://www.epa.gov/ttn/oarpg/t3/fact_sheets/eaf_fs_121707.html

[accessed April 16, 2008.]

168 National Voluntary Mercury Switch Program, EPA Fact Sheet: 

http://www.epa.gov/mercury/switch.htm [accessed April 16, 2008.]

169 SCDHEC.

170 Lehigh Cement, Redding, CA.

171 Vexor Fuels.

172 Holcim/Geocycle, Holly Hill SC; Midlothian TX.

173 Holcim/Geocycle, Devil’s Slide UT.

174 Realff, M., Lemieux, P., Lucero, S., Mulholland, J., Smith P., 2005. Characterization of transient 

puff emissions from the burning of carpet waste charges in a rotary kiln combustor. Cement 

Industry Technical Conference, 2005. Conference Record, as cited in: Murray, A.E., and Price, L., 

2008. Use of Alternative Fuels in Cement Manufacture, Ashley Murray, Energy and Resources 

Group, University of California, Berkeley; Lynn Price, Energy Analysis Department, Environmental 

Energy Technologies Division, Lawrence Berkeley National Laboratory, 2008, Page 26, Page 28.

175 Lafarge, Tulsa OK.

176 Ash Grove Cement.

177 CEMEX, Knoxville TN.

178 Holcim/Geocycle, Dundee MI.

179 Ash Grove Cement, Foreman AR.

180 Lehigh Cement.

181 CEMEX, Knoxville TN.

182 Lafarge, Tulsa OK; Ash Grove Cement, Foreman AR.

183 Lehigh Cement.

184 CEMEX, Knoxville TN.

185 Lafarge, Tulsa OK, CEMEX, Knoxville TN.

186 Shasta County Air Quality District CA; Puget Sound Clean Air Agency WA.

187 Shasta County Air Quality District CA.

188 PADEP SC.

189 Lehigh Cement, Pennsylvania.

190 TXI, Midlothian TX.

191 California Portland Cement, Colton CA.

192 CEMEX, Knoxville TN; California Portland Cement, Colton CA.

193 Lafarge, Seattle WA and Lehigh Cement, Glens Falls NY.

194 Lehigh Cement.

195 Lehigh Cement; Ash Grove Cement

196 CEMEX, Knoxville TN; California Portland Cement, Colton CA.

197 TXI, Midlothian TX.
Cement Sector Trends in Beneficial Use of Alternative Fuels and Raw Materials

116

 

198 California Portland Cement, Colton CA.

199 Lafarge, Seattle WA.

200 Lehigh Cement, Redding CA.

201 South Carolina, Texas.

202 PADEP.

203 California.

204 Systech, Lafarge Sugar Creek MO.

205 Lehigh Cement.

206 Lehigh Cement.

207 CEMEX.

208 Lafarge.

209 See EPA, NPEP Success Story: Motiva Enterprises, 

http://www.epa.gov/osw/partnerships/npep/success/motiva.htm.

210 Berkeley National Laboratory, Energy Efficiency Improvement Opportunities for Cement 

Making, January 2004. See also, EPA, Report to Congress on Cement Kiln Dust, 1993.

211 Berkeley National Laboratory, Energy Efficiency Improvement Opportunities for Cement 

Making, January 2004.

212 Berkeley National Laboratory, Energy Efficiency Improvement Opportunities for Cement 

Making, January 2004.

213 Berkeley National Laboratory, Energy Efficiency Improvement Opportunities for Cement 

Making, January 2004.

214 EPA, Report to Congress on Cement Kiln Dust, p. 2-17. 

215 PCA, U.S. and Canadian Labor-Energy Input Survey, 2000.

216 U.S. Department of Energy, Industrial Technologies Program. Energy and Emission Reduction 

Opportunities for the Cement Industry. (December 2003). 

217 U.S. Department of the Interior, USGS, 2005 Mineral Yearbook: Cement, p. 16.3.

218 PCA. U.S. and Canadian Portland Cement Industry: Plant Information Summary. (2005).

219 Berkeley National Laboratory, Energy Efficiency Improvement Opportunities for Cement 

Making, January 2004.