Project Summary

United States

Environmental Protection

Agency

Recycling of Electric Arc Furnace

Dust: Jorgensen Steel Facility

Risk Reduction

Engineering Laboratory

Cincinnati, OH 45268

Research and Development

The Ek GlassificationTM* process was

evaluated under the Waste Reduction

Innovative Technology Evaluation

(WRITE) Program, a formal program

established by the United States Environmental Protection Agency (EPA) to

accelerate the development of new and

innovative technologies used to recycle

or reduce waste and pollution. The process has potential to effectively reduce

hazardous waste generated in the steelmaking industry (K061-listed waste,

defined as “emission control dust/

sludge from the primary production of

steel in electric furnaces,” 40 CFR

261.32) by recycling Electric Arc Furnace (EAF) dust and converting it into

usable products.

An economic assessment was made

of applying this process to a plant producing approximately 21,000 tons of

product/yr. These estimates indicate

that a profitable operation is possible.

Products range from $2/ton (Portland

cement materials) to $650/ton (glass

ceramics/ architectual tile feedstocks).

Air emissions and process wastewater were not analyzed for this test. For

full scale applications these may need

to be investigated under actual operating conditions.

This Project Summary was developed

by EPA's Risk Reduction Engineering

Laboratory, Cincinnati, OH, to announce

key findings of the research project

that is fully documented in a separate

report of the same title (see Project

Report ordering information at back).

Introduction

The steel-making industry produces a

large amount of Electric Arc Furnace (EAF)

dust as part of normal production. A glass

technology called Ek GlassificationTM

(hereafter called “the Process”) has been

developed by Roger B. Ek and Associates, Inc. (hereafter called “the Developer”)

to recycle this listed waste (K061) and

convert it, along with other byproducts of

the steel-making industry (i.e., spent steel

slags, spent refractories, mill scale, and

grinding swarf), into marketable commodities that are defined as nonleachable by

Toxicity Characteristic Leaching Procedure

(TCLP) protocols. These products may include colored glass and glass-ceramics;

ceramic glazes, colorants, and fillers; roofing granules and sand-blasting grit; and

materials for Portland cement production.

For this project, a portable pilot-scale

process furnace was utilized (see Figure

1). Natural gas burners were used to heat

the furnace to its operating temperature of

approximately 2,500 ̊F. The furnace was

also equipped with molybdenum metal

electrodes for partial or complete electric

heating. The use of natural gas results in

volatilized metal emissions whose levels

are regulated. Electrical resistance heating using electrodes is the preferred

method of supplying heat to the furnace

once the glass has become molten. This

is because of better heat transfer between

the electrodes and the melt and because

no additional volume of pollutants are genEPA/600/SR-95/007 March 1995

* Mention of trade names or commercial products does

not constitute endorsement or recommendation for

use.

Trevor W. Jackson and Jamie Sue Chapman

REVISED COPY

If earlier version

was received,

please discard it.
2

Exhaust

port

Furnace refractory lining

Natural gas

burner nozzle

Batch blanket

Throat

wall

Glass

pouring

through

Refiner

Molybdenum Throat

electrode

Glass batch

port

Melter

Figure 1. Ek GlassificationTM test furnace for EAF dust.

erated by the addition of air and fuel and

the associated products of combustion that

may sweep volatile metals out of the exhaust port. Additionally, the heating takes

place below an insulating blanket of cool

feed material that retains/recondenses

volatile metals.

The glass batch, consisting of the mixture of glass forming ingredients, EAF dust

and other steel mill waste products, forms

an insulating blanket on the surface of the

melted glass in the melter section of the

furnace. As the level of melted glass rises

in the melter, the molten product flows

into the refiner section through a port in

the throat wall. The melted glass can then

be ladled out or allowed to exit via the

pouring trough. For this test, both ladling

and pouring were utilized, the latter enhanced by elevating the feed end of the

furnace. Glass was dispensed either into

molds to form castable products or into a

granulator (water quench) to form granular products. Once ladling or pouring was

complete, the furnace was refilled with

glass batch and the process was repeated.

Procedure

The goal of this project was to evaluate

the effectiveness of the Process in generating a nonleachable product from K061-

listed waste. Testing was performed at

the Earle M. Jorgensen Steel Co. (EMJ),

from July 8 to 10, 1991. Three glass recipes were designed for use at EMJ, identified as Glass I, II and III. The EPA test

program focused on recipe II.

Due to the scope of the effort, the EPA

work was restricted to the collection of

two duplicate samples from each of the

solid products for the Glass II recipe

(granular and castable). A split of each

sample was also taken and given to the

Developer. These samples were subjected

to TCLP and analyzed for the eight RCRA

metals plus zinc, since the leachability

characteristic of the metals in the final

product is the critical parameter that determines if the product meets treatment

standards for K061-listed wastes. The

samples analyzed as part of the EPA program were compared with the analyses of

split samples taken for the Developer. The

complementary sampling and analysis conducted by EPA was to compare the

Developer’s analytical results for (TCLP)

with that of an independent laboratory and

to obtain a “snap-shot” of the process in

operation at the facility. Sampling of the

stack gas for metals emissions was not

implemented during these tests.

Stack gas sampling data were gathered

by Horizon Engineering during earlier, independent tests of the system conducted

at Oregon Steel Mills, Inc. (OSM). These

data, however, were not suitable for projecting full scale performance at EMJ or

for generalizing about regulatory compliance issues for other applications of this

technology. Process quench water generated during the granulation procedure was

also not characterized during this test.

The Developer’s sampling program consisted of the sampling and analysis of all

three glass recipes and included the batch

feed, the glass products (castable and

granular), and other manufactured products made from the glass produced during the tests. These products included

glass ceramic, tile glaze, and three varieties of brick glaze. Process monitoring was

conducted throughout the tests by the Developer.

Representatives of EMJ supplied

samples of feed materials for all of the

tests. The EAF dust sample was taken

directly from the baghouse hopper.

Chemical analysis was performed on

the feed materials to serve as a basis for

mixing the three recipes. The feed materials used for the production of the glass

included EAF dust, spent steel slags, spent

refractories, bricks, mill scale, and grinding swarf.

All feed materials, with the exception

the EAF dust, spent slag, and grinding

swarf, required crushing and screening to

reduce particle size to minus 10 mesh

(U.S. sieve standard).
3

The crushed and screened materials

were placed in steel drums and plastic

pails, labeled, and covered. Weighing was

performed on a 3 ft2 platform scale with a

capacity of 5,000 lb.

Each ingredient for the 260-lb batch

was weighed in a 5-gal plastic pail and

added to a paddle mixer equipped with

plow blades intended for dry mixing of

refractory castables. The blender was covered and sealed to eliminate fugitive dust

emissions. Blending was carried out for at

least one minute in accordance with

blender manufacturer’s recommendations,

followed by visual inspection for homogeneity. To avoid contamination of the

blender with EAF dust, the dust

componentwas hand-blended into the

batch just prior to loading into the furnace.

The furnace was charged with a steel

shovel. At the start of charging, particulate emissions were very noticeable in the

furnace stack. However, once the glass

batch covered the molten glass surface to

a depth of about one inch, the visible

emissions diminished rapidly.

The furnace was located in the steelmelting area of the EMJ plant so that

fugitive emissions could be collected with

the steel plant’s dust collection system

and routed to the baghouse.

Gas burners were used to bring the

furnace up to operating temperature (2,400

to 2,500 ̊F). This operation required approximately 12 hr. Once the operating temperature was reached, the glass batch

was added. Approximately 1-1/2 hr were

required to load one batch. At the completion of loading the batch, electrode tests

were conducted intermittently. The electric heating system utilized two commercial-sized, 1-1/4-in. diameter molybdenum

electrodes. The testing used natural gas

as the primary melt energy. The purpose

of the electric melting tests was to establish melt conductivity, measure the amperage flow at constant voltage and select

glass temperature isothermal conditions.

These data were used to determine the

specifications for transformer equipment

(especially the operating voltage range) to

be used in full-scale operations. The electrodes also provided heat to maintain the

furnace temperature between 2,400 and

2,500 ̊F. Each batch produced about 250

to 300 lb of molten product. Approximately

30 min were required to ladle the glass

into moulds. At the end of the day, the

furnace temperature was dropped slightly

and maintained between 2,200 and

2,300 ̊F during the night.

The Glass II recipe was sampled and

analyzed as part of the EPA testing activities. This recipe was used to prepare glaze,

iron silicate for Portland cement production and sandblasting grit. For the castable

product, the glass was poured into a 6-in.

diameter disc mold to a depth of approximately 2 in. and allowed to cool into a

solid monolith. For the granular product,

the molten glass was quenched with water as it was poured into a storage vessel.

Quenching of the molten glass produced

a granular material known as “frit.”

Duplicate samples of both a castable

product and a granular product were collected at the end of the day of testing. For

the castable product, the solid monolith

was fractured into small pieces (no greater

than 1 in. in diameter) by placing the monolith of glass on a hard surface and striking

the disk with a heavy object. Samples

obtained were split for analysis by both

EPA’s laboratory (NET Pacific, Inc.) and

the Developer’s laboratory (Sound Analytical Services, Inc.) and placed in 1-L

glass jars.

For the case of the granular product,

the complete batch of product was manually homogenized using a drum and stainless steel trowel. Representative aliquots

were then obtained from various random

locations within the drum, split for analysis

by the two laboratories, and placed into

1-L glass jars.

Process monitoring and furnace operating parameter data were gathered by the

Developer. The primary granular, and a

composite of the castable samples were

subjected to the TCLP in accordance with

SW-846 Method 1311 and subsequently

analyzed for eight RCRA metals plus zinc.

Results and Discussion

Samples analyzed by NET Pacific for

EPA indicated low leachability characteristics for metals in the final products as

shown in Table 1. The leachable metal

content in both the castable and the granular samples was within the TCLP limits for

all compounds for which they were analyzed. Barium, chromium, lead, and zinc

were the only compounds detected in either of the EPA samples. Comparison of

these data to those obtained by Sound

Analytical Services, Inc. (see Table 1) produced similar results (for the granular product only) even though the Developer’s

laboratory could not achieve the same

detection limits as the EPA laboratory.

TCLP analyses were performed on

Glasses I and III by the Developer’s laboratory. The results of these analyses indicated that the products are within the TCLP

leaching maximums.

Stack gas sampling data were previously gathered during earlier tests at the

Oregon Steel Mill (OSM). Although these

data suggest acceptable air emissions,

the data are of questionable quality because they do not satisfy EPA stack testing protocols and standards.

Cost estimates were performed for the

OSM plant. A full-scale system producing

60 tons of glass/day, and operating 350

EPA Castable EPA Granular Developer

Sample2 Sample2 Granular Regulatory

EPA HW No.1 Contaminant (mg/L) (mg/L) Sample (mg/L) Level3 (mg/L)

D004 Arsenic <0.0025 <0.0025 <0.2 5.0

D005 Barium 0.043 0.025 <0.1 100.0

D006 Cadmium <0.0035 <0.0035 <0.1 1.0

D007 Chromium 0.050 0.13 0.1 5.0

D008 Lead 0.067 0.120 <0.1 5.0

D009 Mercury <0.000086 <0.000086 <0.002 0.2

D010 Selenium <0.001 <0.001 <0.3 1.0

D011 Silver <0.0092 <0.0092 <0.1 5.0

—— Zinc 0.95 0.60 0.6 NR

1 Hazardous Waste Number 2 Average of duplicate samples 3 Regulatory levels taken from 40 CFR ch. 1 (7-1-90 Edition), Section 261.24, Table 1

NR Not Regulated

Table 1. TCLP Results and Comparison to Regulatory Limits for Samples from EMJ
4

days/yr would require an initial cost of

$10,500,000 for design, construction and

start up.

For a 10 yr period, the Process could

produce a gross profit of $63,195,000 while

avoiding $43,040,000 in disposal costs,

for a total savings of $106 million, not

including reduced liability benefits, and

avoidance of administrative costs for permits and managing of hazardous waste

under the old system.

The actual savings realized will depend

on the types and amounts of products

sold (at present market conditions, the

lowest value products are cement additives at $2 to $6/ton. The highest value

products, such as glass ceramics and architectural tiles sell from $175 to $650/

ton.

Conclusions

A number of conclusions may be drawn

regarding the Process as a result of this

study:

• The glass product types which were

prepared by the Process and tested

as part of this study resulted in

relatively non-leachable glasses. For

the metals of interest for K061 waste

(calcium, chromium, and lead), these

values were lower than those allowed

under RCRA regulations for TCLP.

• The Process utilizes other (non-listed)

foundry wastes to replace constituents

that would be purchased as virgin

additives for glass-making. Ideally this

results in both a conservation of

resources and recycling of both

hazardous and non-hazardous wastes

at the foundry.

• This project did not focus on

investigating compliance issues in

terms of air emissions and waste

water generated during batch

charging, melting, quenching and

drying of the three glass products. It

is believed that significant variation in

emission species and concentrations

are possible, due to the specific

application and associated operational

procedures.

Compliance issues should be evaluated

on a case-by-case basis at least until fullscale data are accumulated to better identify the variability associated with applying

this technology.

The full report was submitted in fulfillment of contract 68-C8-0062, WA 3-18

SAIC under the sponsorship of the U.S.

Environmental Protection Agency.

Trevor W. Jackson and Jamie Sue Chapman are with Science Applications

International Corporation, San Diego, CA 92121

Ivars Licis is the EPA Project Officer (see below).

The complete report, entitled "Recycling of Electric Arc Furnace Dust:

Jorgensen Steel Facility," (Order No. PB95-167219; Cost: $19.50, subject

to change) will be available only from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at:

Risk Reduction Engineering Laboratory

U.S. Environmental Protection Agency

Cincinnati, OH 45268

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/600/SR-95/007