1
2

Table of Contents

Introduction................................................................................................................................3

Agenda .......................................................................................................................................4

Tutorial.......................................................................................................................................5

Introduction, Project Summary, and Trace Elements By Ronald H. Affolter........................6

Laboratory Setup, How Elements are Analyzed, and Quality Assurance/Quality Control 

(QA/QC) By Jamey D. McCord ...........................................................................................24

Petrology of Feed Coal and Fly Ash By James C. Hower....................................................37

Characterization of Feed Coal and Fly Ash Using X-Ray Diffraction and Microbeam 

Methods By Michael E. Brownfield.....................................................................................52

Leaching Studies by Batch, Sequential, Toxicity Characteristic Leaching Protocol (TCLP), 

and Synthetic Precipitation Leaching Protocol (SPLP) By Cynthia A. Rice .......................68

References................................................................................................................................78

Contact Information .................................................................................................................79
3

Introduction

The principal mission of the U.S. Geological Survey (USGS) Energy Resources 

Program (ERP) is to (1) understand the processes critical to the formation, accumulation, 

occurrence, and alteration of geologically-based energy resources; (2) conduct scientifically 

robust assessments of those resources; and (3) study the impact of energy resource 

occurrence and (or) production and use on both environmental and human health. The ERP 

promotes and supports research resulting in original, geology-based, non-biased energy 

information products for policy and decision makers, land and resource managers, other 

federal and state agencies, the domestic energy industry, foreign governments, nongovernmental groups, academia, and other scientists. Investigations include research on the 

geology of oil, gas, and coal and the impacts associated with energy resource occurrence, 

production, quality, and utilization. The ERP’s main focus on coal is to support 

investigations into current issues pertaining to coal production, beneficiation and (or)

conversion, and the environmental impact of the coal combustion process and coal 

combustion products (CCPs). To accomplish, the USGS combines its activities with other 

organizations, including donor organizations, to address domestic and international issues 

relating to the development and use of energy resources. 

Coal quality, composition of stack emissions, and coal combustion products (CCPs) 

have become major environmental concerns as the rate of coal utilization increases 

nationally. With increasing emphasis on environmental issues, information on the quality of 

coal, which includes ash yield, sulfur content, and heat value, as well as major-, minor-, and 

trace-element content, has become as important as information on the quantity of the 

resource. Therefore, it is important to determine how these elements are distributed in the 

feed coal, the resulting changes in composition as coal is processed, and the chemical 

composition of the CCPs. Because (1) coal-quality data are important to the resource 

classification system (as applied by the USGS), and (2) utilization of coal may be regulated 

for its possible effect on the environment, any evaluation of future coal resource potential 

should therefore consider quality as well as quantity.

It is a widely accepted fact that the environmental “footprint” of coal utilization will 

have to continue to be reduced in the future. One of the basic building blocks to accomplish 

this goal is the development of sound databases that document the relation between 

geological controls on coal quality and the resultant CCPs. An integrated approach to coal 

quality work-- a “cradle to grave” approach-- focuses on more than one aspect of the coal, 

such as how and (or) where different coal quality characteristics form and what happens to 

them through the process of mining, production, transport, utilization, and waste disposal. 

In order to determine these characteristics, an extensive suite of coal-quality analyses, 

mineralogical, petrology, and leaching investigations are performed on samples (both preand post-combustion) taken during different phases of the coal-utilization process. The feed 

coal, fly ash, and bottom ash sampling times are closely coordinated so that feed coal 

samples can be matched as closely as possible with the corresponding CCP samples. The 

goals of these types of study are to follow the flow of coal through the power plant, and 

finally to the disposal or utilization of the various CCPs. The results help to evaluate the 

relation of coal composition to the resultant CCPs, because the content, distribution, and 
4

behavior of elements during and after the combustion process depend in large part on the 

content and distribution of trace elements in the feed coal. With an adequate amount of data 

from these studies, general predictive models could be developed so that issues like ash 

disposal and CCP utilization are addressed with greater precision. 

This type of research fosters a greater understanding of the fate and partitioning of 

elements during coal combustion, and leads to data that can be used to more accurately 

evaluate how coal-quality parameters affect air emissions and waste-disposal efforts. This 

tutorial will (1) examine how these studies are conducted under the Coal Quality and 

Utilization issues task and the importance of providing improved, comprehensive, sciencebased data sets that can be utilized by policy and decision makers; and (2) discuss the history 

of collecting quality USGS data on trace elements, laboratory methods and procedures, 

petrology, mineralogy, and leaching characteristics of CCPs.

Agenda

12:15 p.m. Introduction, Project Summary, and Trace Elements—By Ronald H. Affolter

12:35 p.m. Laboratory Setup, How Elements are Analyzed, and Quality 

Assurance/Quality Control (QA/QC)—By Jamey D. McCord

12:55 p.m. Petrology of Feed Coal and Fly Ash—By James C. Hower

1:15 p.m. Break

1:20 p.m. Characterization of Feed Coal and Fly Ash Using X-Ray Diffraction and 

Microbeam Methods—By Michael E. Brownfield

1:40 p.m. Leaching Studies by Batch, Sequential, Toxicity Characteristic Leaching 

Protocol (TCLP), and Synthetic Precipitation Leaching Protocol (SPLP)—By

Cynthia A. Rice

2:00 p.m. Questions and Answers—By Ronald H. Affolter
5

Tutorial
6

Introduction, Project Summary, and Trace Elements
7

Slide 1

U.S. Department of the Interior

U.S. Geological Survey

Introduction, Project Summary, and 

Trace Elements

By

Ronald H. Affolter 

U.S. Geological Survey, Denver, Colorado

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Slide 2

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Instructor

Ronald H. Affolter

Ron Affolter is a geologist with the U.S. Geological Survey who works 

on coal quality and database issues involving the characterization of 

the chemistry, mineralogy, and overall quality of U.S. and world 

coals. 

Ron has been an integral member of several multidisciplinary research 

teams providing coal quality data and quantity interpretations for the 

Colorado Plateau and Illinois Basin coal Assessment projects. He is 

currently a task leader for both the Coal Quality: Geologic Controls 

and Utilization Issues task and the Laboratory Analytical Issues and 

Quality Databases task. He is also the supervisor for the U.S. 

Geological Survey’s Geochemical Laboratory in Denver, CO and 2nd

Vice Chairman for the Coal Geology Division of the Geological 

Society of America (GSA).
8

Slide 3

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

 History of Collecting Coal 

Quality Data Within the U.S. 

Geological Survey

 U.S. Geological Survey 

Energy Resource Program 

(ERP) 5-Year Plan

 Coal Quality: Geologic 

Controls and Utilization 

Issues Task

 Trace Element Studies

Slide 4

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

History of Coal Quality

 Since 1970, the U.S. Geological 

Survey has pursued a program to 

evaluate the chemical composition 

of coals in the United States. 

 Collection of samples involved a 

cooperative effort among many 

different State and Federal 

agencies, private corporations, 

mines, and utilities. 

 Data consist of geologic, 

stratigraphic, and chemical 

information collected from drill 

holes, face channels, mine 

cuttings, power plants, and outcrop 

samples.
9

Slide 5

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

 Documentation and chemical analyses for most coal 

samples processed during this program are available to the 

public in more than 2,000 reports listed in part by Finkelman 

and others, (1991); Affolter and Hatch, (1995); and Ellis 

(1995).

 These reports list location, depth, thickness, and the basic 

geology of the sampled coal beds and summarize proximate 

and ultimate analyses and major-, minor-, and trace-element 

composition of the coal samples. 

 Bed summaries are also available on the COALQUAL 

Database CD-ROM (Bragg and others, 1997) and individual 

samples on the National Geochemical (PLUTO) Database 

(Baedecker and others, 1998).

Slide 6

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Coal Quality

Because coal quality 

data are essential 

components of the 

U.S. Geological 

Survey's resource 

classification system 

(Wood and others, 

1983),

any evaluation of coal 

resource potential 

must consider quality 

as well as quantity.
10

Slide 7

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

PP-1625A

PP-1625B

PP-1625D

PP-1625C

U.S. Geological Survey's National Coal Resource 

Assessment Areas

Slide 8

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Graduated Symbol Map for Sulfur Content (percent, asreceived basis) of the Herrin Coal in the Illinois Basin
11

Slide 9

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Mercury Concentration in Coal Samples from the 

Colorado Plateau Region

Slide 10

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

World Coal Quality Inventory (WoCQI)
12

Slide 11

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

The Mission of the Energy Resources 

Program (ERP) 

The ERP promotes and 

supports research resulting 

in original, geologically 

based, 

non-biased energy 

information products

for policy and decision 

makers, land and resource 

managers, other federal and 

state agencies, the domestic 

energy industry, foreign 

governments, nongovernmental groups, 

academia, and other 

scientists.

Slide 12

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

The U.S. Geological Survey Energy 

Resources Program (ERP) 5-Year Plan

 Understand the processes 

critical to the formation, 

accumulation, occurrence, 

and alteration of geology 

based energy resources. 

 Conduct scientifically robust 

assessments of those 

resources. 

 Study the impact of energy 

resource occurrence and (or) 

production and use on both 

environmental and human 

health. 
13

Slide 13

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Coal

 Improve the understanding of the 

coal endowment of the United 

States. 

 Maintain state-of-the-art data 

management and data distribution 

systems in order to organize, 

provide ease of use, archive, and 

deliver critical ERP information 

both internally and externally. 

 Partner with other organizations, 

including donor organizations, to 

address domestic and international 

issues regarding energy 

resources. 

Slide 14

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Given increasing attention on 

the impacts of coal utilization, 

coal-quality research must 

address a more 

comprehensive suite of coal 

quality-related issues beyond 

fundamental coal quality 

parameters (such as ash 

yield, sulfur content, and 

heating value) and

develop the possibility for a 

predictive capability

addressing the effect of 

variations in spatial 

occurrence and coal 

utilization processes. 

Proposed Direction
14

Slide 15

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

The ERP should focus 

research efforts to support 

investigations into the current 

issues pertaining to 

coal production and 

beneficiation, and the impact of 

the coal combustion process 

and coal combustion products 

(CCPs). 

Also provide information and 

data on a variety of coal quality 

parameters including sulfur, 

nitrogen, major-, minor-, and 

trace-elements, and coal 

mineralogy.

Slide 16

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

 Compile quality chemical information on the coals 

currently being mined and utilized throughout the 

United States. Evaluation of the distribution of 

element contents with emphasis between the feed 

coal and various coal combustion product (CCP) 

components.

 Relating that information to the geologic framework 

and possible environmental problems.

Coal Quality: Geologic Controls and 

Utilization Issues Task
15

Slide 17

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

 Studies should focus on how or where different 

quality parameters form and (or) occur, what happens 

to them through mining, production, transport, and, 

most importantly, utilization.

 Batch, flow through column, and sequential leaching 

studies to evaluate either disposal scenarios or to 

selectively dissolve mineral matter and help support 

microprobe, scanning electron microscope (SEM), 

and X-ray diffraction (XRD) analysis of selected 

inorganic elements.

Coal Quality: Geologic Controls and 

Utilization Issues Task--Continued

Slide 18

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Coal Mine

Power Plant CCPs

Coal Deposit

•Mine product (selective mining)

•Product trace element chemistry

•Modes of occurrence

•Depositional environment

•Trace element chemistry

•Modes of occurrence

•Feed coal

•Trace element chemistry

•Modes of occurrence

•Temporal variation

•Fly ash / bottom ash

•Trace element chemistry

•Modes of occurrence 

•Temporal variation
16

Slide 19

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Mine

Landfill

Modified from EERC (2006).

Utilization

Slide 20

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly ash concrete used in 

decking and piers of the 

Sunshine Skyway Bridge, 

Tampa Bay, Florida*

Gypsum produced by wet 

scrubbers was used in the 

manufacture of wallboard*

*Modified from Schweinfurth, S.P. (2003)
17

Slide 21

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

COMPONENTS IMPACTS

Chemical

Mercury, lead, arsenic,

selenium, others

•Power plant 

efficiency

Mineralogical

Iron-sulfide,

quartz, others

Petrological

Macerals, reflectance

•Coal combustion 

products

•Water quality

•Air quality

•Solid waste 

disposal

Coal

Quality

Slide 22

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Periodic Table of Naturally Occurring Elements

Blue=MAJOR EL EMENTS Modified from, Schweinfurth (2003) 

Orange=MINOR ELEMENTS

Yellow=TRACE ELEMENTS

Green=HAZARDOUS AIR POLLUTANTS (HAPs)
18

Slide 23

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Western U.S. Colorado Plateau Interior Province

ELEMENT Tertiary coal Cretaceous coal Pennsylvanian

ppm whole coal Mean Value Mean Value Mean value

Antimony 0.63 0.48 1.1

Arsenic 7.4 1.6 11

Beryllium 1.1 1.2 2

Cadmium 0.1 0.1 0.43

Chromium 10 4.5 15

Cobalt 3.5 1.5 7

Lead 4.2 6.5 30

Manganese 60 22 70

Mercury 0.12 0.06 0.15

Nickel 4.6 3.7 20

Selenium 0.72 1.2 2.8

Uranium 1.7 1.3 1.8

ppm= parts per million

Slide 24

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Previous Studies

 Kentucky- Multiple sources from Illinois 

and Appalachian Basins

 Indiana-Powder River Basin, Wyoming 

(7 mines-Wyodak/Anderson coal zone)

 Washington-Blend of Powder River 

Basin (Spring Creek) and Washington 

coal
19

Slide 25

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Temporal Variation of Elements in Feed Coal 

and Fly Ash from a Kentucky Power Plant

Slide 26

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Variation in Arsenic Content by 

Sampling Scheme
20

Slide 27

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Variation in K2O Content by Sampling Scheme

Slide 28

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Distribution of Arsenic, Barium, Na2O, and MgO

In Various Types of Samples
21

Slide 29

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Old sampler

New sampler

Slide 30

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Current Studies

 Indiana power plant

 Ohio power plant

 Wyoming power plant

 New Mexico (planning)

 Colorado (planning)

 Alaska ?

 Texas ?
22

Slide 31

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Benefits and Extensions of this 

Proposed Work

 There seems to be a lack of solid data, especially with regard 

to trace elements in the by-products. These studies could aid 

coal by-product utilization research.

 The creation of improved, practical databases to assist policy 

makers in making more informed decisions. 

 Maintain high analytical standards (QA/QC) for the Energy 

Program Geochemistry Laboratory. 

 Address coal ash disposal issues.

QA/QC=Quality Assurance/Quality Control

Slide 32

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Benefits to Contributors 

Data on Feed Coal and CCPs

 Trace element 

 Proximate/ultimate, forms-of-sulfur, ash fusion temperatures, 

heat value

 Mineralogy (XRD, SEM, Microprobe)

 Petrography

 Leaching

 Interpretation of data

 Special samples
23

Slide 33

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

 Private energy companies

 Environmental groups

 Consultants

 Educators, universities

 Utilities 

 Other government agencies – DOE, EIA, NPS, BLM, NRC, 

EPA, SEC, OSM, State Geological Surveys (COOP)

 ASTM International

 American Coal Ash Association (ACAA)

There are Many Challenges, Especially Getting 

Cooperation from Mines and Utilities for Obtaining 

Representative Samples
24

Laboratory Setup, How Elements are Analyzed, and Quality 

Assurance/Quality Control (QA/QC) 
25

Slide 34

U.S. Department of the Interior

U.S. Geological Survey

Laboratory Setup, How Elements are 

Analyzed, and Quality 

Assurance/Quality Control (QA/QC)

By

Jamey D. McCord 

U.S. Geological Survey, Denver, Colorado

Slide 35

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Instructor

Jamey McCord is a physical scientist for the 

Central Region Energy Resource Team in 

Denver, Colorado. He has been with the U.S. 

Geological Survey for 12 years and is 

responsible for overseeing lab operations and 

maintaining the laboratory information system 

(LIMS). His primary focus is on coal, oil, and 

gas geochemistry. 

Jamey D. McCord
26

Slide 36

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

USGS Energy Program Geochemistry 

Laboratory Capabilities

 Rock and coal

 Water

 Plant

 Gas and oil

Slide 37

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Analysis Offered

 ICP (Inductively Coupled Plasma)

 ICPMS (Inductively Coupled 

Plasma Mass Spectrometer)

 GFAA (Graphite Furnace Atomic 

Absorption)

 Hydride / Cold vapor 

 Sulfur by direct read

 Chloride by direct read

 Ash-Moisture-LOI (Lost on ignition)

 Custom analysis and method development

Dragoset and others (2003)
27

Slide 38

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

ICPAES (Inductively Coupled Plasma )

ICPAES is used to analyze major and trace elements in 

coal. It is capable of attaining values in the low parts 

per billion (ppb) range. 

Slide 39

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

ICPMS (Inductively Coupled Plasma Mass Spectrometer)

ICPMS is capable of 

analyzing coal to 

low parts per billion 

(ppb). It is also 

used for rare earths 

and limited isotopic 

ratioing.
28

Slide 40

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Sample Digestions for ICP and ICPMS

After the coal is received it 

is ashed and put through 

the appropriate digestion 

for the desired analyses.

Slide 41

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Different Digestions for ICP/ICPMS

Major Digestion

 Weigh 0.1 gram ash (LOI 750oC)

Trace Digestion

 Weigh 0.2 gram ash (LOI 500oC)

Sinter Decomposition

 Weigh 0.1 gram ash (LOI 500oC)

LOI= Lost on ignition
29

Slide 42

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Mercury Analysis

HG analysis is done two ways:

 Direct read on the DMA (Direct 

Mercury Analyzer)

 Hydride generation on the FIMS 

(Flow Injection Mercury System) Mercury Ore

Slide 43

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Chloride Analysis

Tox-100 Direct Read 

Chloride Analyzer 

detects chloride 

down to 10 ppm 

compared to IC 

(Ion Chromatography)

detection limits of 

500-1,000 ppm.

ppm= Parts per million
30

Slide 44

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Sulfur Analysis

LECO SC-432 for 

direct analysis 

of sulfur in coal. 

A coal industry 

standard for 

years. 

Slide 45

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Selenium Analysis

AA-200 used with a heating mantel and a flow injection 

system for selenium analysis. Detection limits are 

around 1ppm in coal.

ppm= Parts per million
31

Slide 46

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Low Temperature Ashing

Low temperature ashing is done to preserve the crystal 

structure of minerals while removing organic matter 

that would interfere with X-ray diffraction analysis.

Slide 47

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction (XRD)

We have two X-ray diffraction units to provide 

mineralogical analysis. The Panalytical Expert-Pro is 

new and is making a big impact on how long it takes to 

analyze samples. 
32

Slide 48

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Example of XRD Scan from New 

and Old

The new XRD will bring speed and better mineral 

determinations.

10 20 30 40 50 60 Two-Theta (deg)

x103

10

20

30

40

50

60

Intensity(Counts)

[USGS3_USGS3 TAFA 1-2-2 Fine Long Scan.xrdml] USGS3 TAFA 1-2-2 Fine Long Scan

10 20 30 40 50 60 Two-Theta (deg)

0

1000

2000

3000

4000

5000

Intensity(Counts)

[TAFA_122_t24.MDI] TAFA 122 (sp 2 of 3), Fly Ash, Centralia, WA; Siem40/30, 24 hr run, 0.02st 28s d

24 Hour Old 1 Hour New

Slide 49

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Geochemical Testing

Geochemical Testing is the contract laboratory used 

by the USGS Energy Resource Team to grind and 

split samples and to provide proximate and ultimate 

analysis.

Geochemical Testing has been quality control tested by 

the USGS Energy Resource Team and has been a 

part of the lab audit.
33

Slide 50

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Organic Lab Capabilities

API (Amer. Petroleum Inst.) gravity and weight percent sulfur

Whole oil GC-FID (Gas Chromatography Flame Ionization Detector) 

nC3 thru nC40

Column chromatography

Saturate, aromatic, resin and asphaltene (SARA)

GC-FID (Gas Chromatography Flame Ionization Detector)

Bitumen, saturate and aromatic fractions

GC-MS (Gas Chromatography Mass Spectrometer) biomarker 

analysis

Whole oil 

Bitumen, saturate and aromatic fraction

Isotope ratio mass spectrometry (IRMS)

Whole oil bitumen, saturate and aromatic fraction

Petrography and vitrinite reflectance

Soxhlet extraction (bitumen)

Elemental analysis

Slide 51

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Quality Control in the Laboratory

The Energy Program Geochemistry Laboratory uses a 

three-tiered approach to quality control (QC). 

 The First Tier 

Method Performance: QC samples are analyzed by laboratory personnel. 

At this level, laboratory personnel use the QC sample data to control the 

analytical process for each batch of samples. If the acceptance criteria are 

not met, the analysis is discontinued until corrected.

 The Second Tier

Data Review and Blind Sample Programs: Laboratory personnel use data 

from these programs to monitor method performance throughout the 

laboratory and for long term tracking. 

 The Third Tier

Performance-Evaluation Studies: These studies are managed by private 

laboratories, local, State, and Federal agencies, all external to the Energy 

laboratory. Data from these studies can be used to compare laboratories 

or to select a laboratory for analytical work. Summary reports from many 

of these studies will be available on the Energy Program Geochemistry 

Laboratory web page.
34

Slide 52

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

First Tier: Method Performance

 Energy laboratory personnel trying to determine elements in any 

sample evaluate two areas of performance: (1) instrument and (2) 

method. Accurate instrument operation can be verified by analyzing 

known standards at different concentrations. Blank water, which has 

negligible concentrations of the constituents of interest, is also 

analyzed to evaluate and eliminate potential sources of bias.

 The analyst uses QC samples to assess whether the method is working 

properly. Data produced from these samples are the most useful for 

customers to evaluate the labs entire analytical process. In addition to 

blank samples, standard reference materials are the primary tools for 

evaluating method bias and variability. Laboratory replicate data are 

also used to evaluate and obtain method variability information. 

 Standard Reference Materials (SRMs) are obtained through internal and 

external sources, such as NIST, CANSPEX, USGS, and EPA. The SRM 

is thought to be sufficiently tested to be used to assess method 

performance. Several SRMs of differing concentrations and elements 

are analyzed alongside everyday samples. The SRM data are evaluated 

to assess bias for each analysis. Additionally, as the data are compiled, 

long-term estimates of method variability can be obtained. 

Slide 53

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Data Review Program. All Energy laboratory analytical results initially are 

stored in the Laboratory Information Management System (LIMS) data 

base. A QC check is done by the laboratory manager to review all 

analytical results in the data base. Examples of QA checks include the 

following:

 Duplicate within limits

 SRMs fall within limits

 Internal blinds tests

 Internal standards

 Historical trends checked if available

 Correlation is within limits

 Proper amount of QA used in job

Blind Sample Programs. The blind sample programs are administered by 

internal and external personnel to the Energy laboratory. The internal 

program quantifies bias caused by random laboratory contamination. 

The external blind checks method performance and reproducibility.

Second Tier: Data Review and Blind Sample 

Program
35

Slide 54

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Third Tier: Performance-Evaluation Studies

The Energy laboratory participates in the following 

national and international inter-laboratory 

performance-evaluation studies: USGS Branch of 

Quality Systems Evaluation Program for Standard 

Reference Samples; CANSPEX

Slide 55

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Outside Audit and Blind Program

 The laboratory has gone through an outside audit to 

ensure its operations are consistent with the 

requirements of good laboratory practices specified 

in ISO 17025, ASTM D4621-99, and D4182-97.

 The laboratory also participates in a blind sample 

program and various round-robin sample programs 

to assure analytical quality. 
36

Slide 56

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Energy Program Geochemistry Laboratory

 Geology

 Mineralogy

 Chemistry

All used to help with questions and arising problems 

in the coal, oil, and gas environment.

Dragoset and others (2003)
37

Petrology of Feed Coal and Fly Ash
38

Slide 57

U.S. Department of the Interior

U.S. Geological Survey

Petrology of Feed Coal and Fly Ash

By

James C. Hower 

University of Kentucky, Lexington

Slide 58

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Instructor

Jim Hower is an adjunct professor at the University of Kentucky with his primary work conducted 

in the Environmental & Coal Technologies Group at 

the Center for Applied Energy Research. With the 

cooperation of the Kentucky Geological Survey and the 

U.S. Geological Survey, he maintains research in the petrology and 

geochemistry of coals. Much of the research is directed toward the 

utilization of coal and of products derived from coal. Recent 

research has focused on the mercury content of fly ash carbons.

Jim is the editor-in-chief of the International Journal of Coal Geology, 

was an author of the Atlas of Coal Geology (AAPG and The Society 

for Organic Petrology), and is the Eastern Region Director for the 

Combustion Byproducts Recycling Consortium 

(http://wvwri.nrcce.wvu.edu/CBRC/), a national program funded by 

the U.S. Department of Energy.

James C. Hower
39

Slide 59

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography

 Inorganic 

neoformed

 glass

 70 to >90% of most FA

 mullite

 spinel

 Inorganic 

coal derived

 Quartz

 Organic 

neoformed

 isotropic coke

 anisotropic coke

 Organic

coal (or fuel) derived

 inertinite

 petroleum coke

Slide 60

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography--Continued

Glass, including glassy 

edge of partially vitrified

shale fragment (left)
40

Slide 61

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography--Continued

Spinel (magnetite)

Isotropic 

coke

Glass

Slide 62

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography--Continued

Mullite
41

Slide 63

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography--Continued

Quartz (top);

Vitrified rock fragment 

(right)

Slide 64

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography--Continued

Inertinite

Anisotropic coke
42

Slide 65

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography--Continued

Partially combusted coal

Slide 66

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Petrography--Continued

Petroleum coke

Biomass 

(Rice hull ash)

Tire-derived fuel ash (right)

with coal-derived carbons
43

Slide 67

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Chemistry

 Volatile trace elements display different 

characteristics in the ash-collection system

 Arsenic, lead, zinc, and others will tend to be more highly 

concentrated in back rows of electrostatic precipitators 

(ESP)

 Flue gas temperature decreases in direction away from 

boiler

 Fly ash particle size decreases towards back rows

 Therefore, cooler temperature (T ) and greater surface area

 Most volatile elements, Hg is exception, tend to be 

associated with inorganic fly ash constituents

Slide 68

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Chemistry--Continued

Example from an eastern Kentucky 

power plant burning mid-S hvAb coal

As Distribution (ppm)
44

Slide 69

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Chemistry--Continued

Selenium shows trends 

that are less distinct 

than latter elements

 Some power plants do 

show distinct increase 

towards cooler rows 

 Others, as on next slide, 

show a distinct peak in 

warmer row

 More detailed study is 

underway

Slide 70

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Chemistry--Continued

Se Distribution (ppm)
45

Slide 71

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Chemistry--Continued

Mercury capture by fly ash is complex, depends on:

 Speciation of Hg in flue gas

 T at collection point

 Amount of carbon in fly ash

 Type of carbon in fly ash

Hg

Slide 72

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fly Ash Chemistry--Continued

Factors influencing Hg speciation include:

 Coal rank influences on combustion temperature

 Amount of Cl in coal (greater in eastern US coals)

 Enhances oxidation

 Amount of Ca in coal (greater 

in western US coals)

 Inhibits oxidation

 Fe-oxides (greater in eastern

coals) may catalyze 

oxidation of Hg
46

Slide 73

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash

Studies have demonstrated relations among:

 Amount of fly ash carbon and Hg capture

 More C = More Hg

 Decreasing flue gas T and Hg capture

 Lower T = More Hg

 Fly ash carbon type and Hg capture

 Increased Hg from inertinite to isotropic coke to anisotropic 

coke

Slide 74

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash--Continued

Unit 1 Fly Ash Carbon vs. Hg

Carbon (%, ultimate analysis)

0 2 4 6 8 10 12 14

Hg (ppm)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Carbon vs Hg 

Hower and others (1999)
47

Slide 75

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash--Continued

Studies have demonstrated relations among:

 Amount of fly ash carbon and Hg capture

 More C = More Hg

 Decreasing flue gas T and Hg capture

 Lower T = More Hg

 Fly ash carbon type and Hg capture

 Increased Hg from inertinite to isotropic coke to anisotropic 

coke

Slide 76

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

10.5/

0.07

19.6/

0.10

7.4/0.50

Mechanical 

separation

Baghouse 

separation

Gas flow Gas flow

12.7/

0.08

5.7/0.50

7.0/0.53

7.2/0.55

14.0/

0.06

Unit 1

364 oC

172 oC

Key: 

C (ultimate analysis)/Hg (ppm)
48

Slide 77

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash--Continued

Appalachian coal: C vs. Hg Relationship with carbon and temperature

C (%, ultimate analysis)

2 4 6 8 10 12 14 16 18 20 22

Hg (ppm)

0.0

0.1

0.3

0.4

0.5

0.6

ultimate C vs mechanical Hg 

ultimate C vs baghouse Hg 

Unit 1

Unit 2

Unit 2

Unit 1

Hower and others (2000)

Note greater 

concentration of Hg 

in cooler baghouse 

hoppers compared to 

concentration in 

mechanical hoppers, 

despite higher C 

in latter 

Slide 78

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash--Continued

Studies have demonstrated relations among:

 Amount of fly ash carbon and Hg capture

 More C = More Hg

 Decreasing flue gas T and Hg capture

 Lower T = More Hg

 Fly ash carbon type and Hg capture

 Increased Hg from inertinite to isotropic coke to anisotropic 

coke

 Surface area increases along same trend
49

Slide 79

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash--Continued

 Collected mechanical fly ash at 

70 MW unit 3 at East Kentucky 

Power’s Dale Station

 Screen ash at 140 mesh (106 

microns)

 Concentrate C with 

triboelectrostatic separation

 Isolate C forms through 

density-gradient centrifugation 

(right)

 Petrographic and chemical 

analyses of DGC splits

Hower and others (2000)

Maroto-Valer and others (2001)

Slide 80

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Dale: DGC concentrate vs. Hg content

Sample

parent 2 5 6 7 8 11 12

Hg (ppm)

0.12

0.14

0.16

0.18

0.20

0.22

Sample vs Hg (ppm) 

Inertinite

Isotropic coke

Anisotropic coke

Intermediate

Intermediate

Isotropic coke

Anisotropic coke
50

Slide 81

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash--Continued

Mardon and Hower (2004)

Study of single-seam/ 

single-mine coal burned 

at 220-MW utility boiler 

(USGS NaCQI-funded 

study)

Hg Distribution by Hopper

Slide 82

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fundamental Relations of Mercury with 

Fly Ash--Continued

Maximum Temperature, oC

0 100 200 300 400 500

%Hg remaining

0

20

40

60

80

100 mechanical

ESP

Rubel and others (2006)

Hg in fly ash has a 

reasonably good 

thermal stability, 

remaining in fly ash 

until 300-400oC range.

Good indicator for 

stability in industrial 

utilization of fly ash. 
51

Slide 83

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Summary

 Fly ash has constituents that 

can be identified 

microscopically.

 Combination of inherited and 

neoformed constituents from 

coal and, in some cases, from 

other fuels or contaminants

 Composition of fly ash is a 

function of chemistry of feed 

coal and other fuels, flue gas T 

at collection point, and fly ash 

petrology among other factors.
52

Characterization of Feed Coal and Fly Ash Using X-Ray Diffraction and 

Microbeam Methods
53

Slide 84

U.S. Department of the Interior

U.S. Geological Survey

Characterization of Feed Coal and Fly 

Ash Using X-Ray Diffraction and 

Microbeam Methods

By

Michael E. Brownfield 

U.S. Geological Survey, Denver, Colorado

Slide 85

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Instructor

Michael Brownfield is a geologist with the U.S. 

Geological Survey in Denver, Colorado where he 

conducts studies on modes of occurrence of 

elements in coal and coal combustion products 

utilizing X-ray diffraction and microbeam 

techniques. Recent studies have focused on the 

characterization of feed coal and coal combustion 

products at an Indiana power plant burning 

Powder Basin coal and the characterization of 

coals and the modes of occurrence of elements 

(including Hg) from the Eocene Puget Group, 

John Henry No. 1 mine, King County, Washington.

Michael E. Brownfield
54

Slide 86

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Characterization of Feed Coal and 

Fly Ash

 Coal is a complex combustible rock made up of organic 

and inorganic mineral components.

 During combustion, elements present in the organic and 

mineral components of the coal are transformed into new 

gaseous and solid phases.

 In fly ash, elements may be uniformly distributed, 

enriched in certain grains or areas of grains, or present 

as coatings on grains or absorbed onto grain surfaces.

Slide 87

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Characterization of Feed Coal and Fly 

Ash--Continued

• Particle size, coal rank, amount of ash, coal mineralogy, 

and trace element content are important variables in 

controlling the combustion of coal and the mobility of 

elements in coal.

• For fly ash, the composition of the feed coal, combustion 

conditions, size of the fly ash particles, and fly ash 

mineralogy influence the distribution and mobility of trace 

elements.
55

Slide 88

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Mineralogy of Feed Coal and Fly Ash

Determination of minerals in coal and fly ash is 

important because minerals can affect:

 Coal combustion and fly ash utilization and disposal

 Location (modes of occurrence) and leachability of 

elements in coal and fly ash

 Acidity (pH) during interaction with water 

Slide 89

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Mineralogy of Feed Coal and Fly Ash--

Continued

Many of the examples in this discussion of 

mineralogy of feed coal and fly ash are from a 

study involving a power plant that was utilizing 

feed coal from the Wyodak-Anderson coal zone in 

the Powder River Basin, Wyoming*.

*Brownfield and others (2005)
56

Slide 90

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis

Coal ash, for X-ray diffraction mineralogical 

studies, is derived by two methods:

 Low-temperature ashing (LTA) and

 Digesting the coal with aqueous sodium hypochlorite 

(NaOCl) or chlorine bleach

Slide 91

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis--Continued

X-ray diffraction methods:

 X-ray diffraction data of bulk LTA and fly ash samples are 

digitally collected and analyzed. Relative abundance of 

minerals can be determined using reference intensity 

methods. 

 Quantitative mineral data are determined on LTA ash and 

fly ash with Rietveld Refinement XRD methods (Larson 

and Von Dreele, 1994) using General Structure Analysis 

System (GSAS) and Materials Data Inc. (MDI) software. 

Rutile (TiO2) can be added as a standard to determine 

amorphous material. 
57

Slide 92

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

 X-ray diffractogram 

of low-temperature 

ash (LTA) from the 

Wyodak-Anderson, 

Powder River Basin, 

Wyoming

 Mean ash yield = 

5.5 weight percent 

X-Ray Diffraction Analysis--Continued

Slide 93

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis--Continued

Quartz Subhedral crystal of 

calcite
58

Slide 94

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis--Continued

Kaolinite–Al2Si2O5(OH) Subhedral crystal of gorceixite–

BaAl3(PO4)2(OH)5

.H2O

Slide 95

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis--Continued

 X-ray diffractogram of 

fly ash derived from a 

Wyodak-Anderson 

feed coal, mined from 

the Powder River 

Basin, Wyoming

 Mean amorphous 

content = 60.4 percent, 

determined using 

General Structure 

Analysis System 

(GSAS) Rietveld 

software 
59

Slide 96

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis--Continued

Fly ash grain derived 

from a feed coal mined 

from the WyodakAnderson coal zone, 

Powder River Basin, 

Wyoming.

Slide 97

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis--Continued

 X-ray diffractogram of 

bottom ash from the 

Wyodak-Anderson 

coal, Powder River 

Basin, Wyoming

 Bottom ash contains 

lesser amounts of 

amorphous material 

because of the 

increase in cooling 

time
60

Slide 98

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

X-Ray Diffraction Analysis--Continued

SEM image of a bottom 

ash grain from an 

Indiana power plant 

utilizing the WyodakAnderson coal from the 

Powder River Basin, 

Wyoming.

Slide 99

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis

Two electron microbeam instruments are 

utilized in the collection of coal and fly ash 

chemical and modes of occurrence data:

 Electron Probe Microanalyzer (EPMA), 

commonly known as a microprobe

 Scanning Electron Microscope (SEM)
61

Slide 100

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

Sample preparation:

 Polished epoxy-bound sections of coal and fly 

ash are prepared for the Electron Probe 

Microanalyzer and Scanning Electron 

Microscope.

 Low-temperature ash and sodium hypochloritetreated samples are mounted on conductive 

carbon tape.

Slide 101

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

The microprobe can collect both quantitative and 

semiquantitative chemical data:

 Quantitative chemical data (generally within ± 1 percent) 

on macrocrystalline phases greater than 5μm) using 

EPMA wavelength dispersive spectral (WDS) analysis is 

conducted using standards

 Semiquantitative analysis using energy dispersive X-ray 

analysis (EDS)
62

Slide 102

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

X-ray intensity mapping with 

the microprobe:

 Very good in determining 

relative abundances and 

distribution of elements in a 

fly ash or bottom ash grain

 Can take as much as 8 hours 

to map a fly ash grain

Chromium, nickel, and silica in a 

ferrite-rich fly ash grain

Slide 103

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

Scanning Electron Microscope analysis (SEM):

 Imaging: using backscattered electron images 

(BEI) or secondary electron images (SEI) 

 Semiquantitative analysis using Energy 

dispersive X-ray analysis (EDS)

 X-ray element intensity mapping, SEM scans are 

faster when compared to the microprobe
63

Slide 104

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

Euhedral beta-form quartz 

from digested coal.

Authigenic quartz that replaced 

plant matter, from digested coal. 

SEM Imaging

Slide 105

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

Euhedral crystal of zircon 

(ZrSiO4) from digested coal.

SEM Imaging

Irregular cleavage fragment of 

K-feldspar from digested coal.
64

Slide 106

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

SEM Imaging

Secondary electron image (SEI) 

showing cinnabar (HgS), iron–

magnesium oxide, and quartz 

in a polished sample of washed 

coal (specific gravity of 1.5 

g/cm3) from the Franklin No. 12 

coal bed in the John Henry No. 

1 mine, King County, 

Washington.

Slide 107

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

SEM Imaging

Secondary electron image 

(SEI) arsenic sulfide 

(realgar, AsS) from a 

washing plant reject 

sample from the Franklin 

7–8 coal bed, John Henry 

No. 1 mine, King County, 

Washington.
65

Slide 108

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

Ca+Mg- rich fly ash grain 

derived from a WyodakAnderson feed coal.

Phosphorus-rich fly ash grain 

derived from a Wyodak-Anderson 

feed coal.

SEM Imaging

Slide 109

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Microbeam Analysis--Continued

X-ray element intensity 

mapping:

SEM backscattered image 

(BEI) showing bright anhydrite 

(CaSO4) and element X-ray 

intensity maps showing 

relative abundances and 

distribution of sulfur (S), 

calcium (Ca), and magnesium 

(Mg) from a fly ash grain 

derived from the a WyodakAnderson feed coal, Powder 

River Basin, Wyoming. 
66

Slide 110

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Conclusions

X-ray diffraction and microbeam analysis of feed coal and 

CCPs are important tools in the characterization of feed 

coal and fly ash.

Determination of minerals and the chemistry of amorphous 

materials in coal and fly ash are important because these 

compounds can affect:

 Coal combustion and fly ash utilization and disposal;

Location (modes of occurrence) and leachability of elements; and

Acidity (pH) during interaction with water

Slide 111

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Radiographic Analysis

Distribution of uranium in fly and bottom ash particles 

can be directly observed using fission-track 

radiography:

• Polished thin sections of grains of fly and bottom ash are 

prepared and irradiated with neutrons.

• During irradiation, fission fragments recoil from the surface of 

the thin section and pass into an overlying sheet of muscovite 

detector material causing linear paths of damage or tracks.

• High fission-track density can be related to areas of high 

uranium concentration in the sample.
67

Slide 112

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Radiographic Analysis--Continued

Photograph (left) of a Ca-P rich fly ash grain and its fission 

track radiograph. Size of images is about 0.25 by 0.15 mm. 

Slide 113

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Radiographic Analysis--Continued

Photography (left) of fly ash 

grains with mineral 

inclusions and its 

radiograph (right). Bright 

mineral inclusions are 

quartz and contain very low 

concentrations of uranium. 

Size of images are about 1.0 

by 0.6 mm. Sample is fly 

ash derived from a WyodakAnderson feed coal, mined 

from the Powder River 

Basin, Wyoming.
68

Leaching Studies by Batch, Sequential, Toxicity Characteristic Leaching 

Protocol (TCLP), and Synthetic Precipitation Leaching Protocol (SPLP)
69

Slide 114

U.S. Department of the Interior

U.S. Geological Survey

Leaching Studies by Batch, Sequential, 

Toxicity Characteristic Leaching 

Protocol (TCLP), and Synthetic 

Precipitation Leaching Protocol (SPLP)

By

Cynthia A. Rice 

U.S. Geological Survey, Denver, Colorado

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Slide 115

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Instructor

Cynthia A. Rice

Cyndi Rice is a retired U. S. Geological Survey scientist.

She received a master’s degree from the Colorado 

School of mines in geochemistry with an emphasis in 

aqueous geochemistry.

Cyndi has investigated the leaching behavior of trace elements in studies 

focusing on a power plant that utilized multi-source high and low S 

coals and a power plant that utilized a sole-source low S coal. More 

recently, Cyndi has devoted all of her time to environmental issues 

associated with the development of coalbed natural gas (CBNG). 

These studies include the characterization of waters co-produced with 

CBNG in the Ferron Sandstone in Utah and in the Fort Union Formation 

in the Powder River Basin. In addition, the interactions between CBNG 

water and the shallow subsurface are focuses of her studies.

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial
70

Slide 116

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Trace Elements in Coal and Coal

Combustion Residues

 Important for recycling and disposal 

 What factors control trace element leaching 

and mobility?

 How can we characterize the material to 

understand trace element leaching and mobility? 

Slide 117

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Controls on Element Leaching and 

Mobility

 Solubilities of initial phases

Surface coatings, oxides readily soluble

Sulfates, carbonates varyingly soluble 

Arsenates, vanadates, selenates varyingly soluble

Silicates, spinel groups sparingly soluble

 Adsorption of elements

Cd, Cu, Mn, Ni, Zn adsorb at high pH

As, Mo, Se, and V desorb at high pH

 Aqueous chemistry

Cationic vs. anionic behavior

 Secondary phase formation

Fe and Al oxyhydroxides, ettringite

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial
71

Slide 118

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Fast Reactions: Seconds to Minutes

Oxide Hydrolysis

CaO + H2O Ca2+ + 2OHCoatings and Carbonates Dissolve

Secondary Phase Formation

AlK(SO4)2 + H2O AlOH2+ + K+ + 2SO4

- + H+

FeOH2+ + OH- FeOOH + H+

Slide 119

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Intermediate to Slow Reactions:

Days to Months

Glass Hydrolysis

NaAlSi2O6 + 2H2O Na+ + Al3+ + 2SiO2(aq) + 4OHSecondary Phase Formation

CO2 Equilibration

2Al3+ + 3SO4

2- + 6Ca2+ + 38H2O Ettringite + 12H+

2CO2 + Ca2+ + 2H2O CaCO3 + HCO3

- + 3H+
72

Slide 120

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

pH

Adsorption

Trace element leaching and mobility

Secondary

phases

Aqueous

speciation

Solubility

“Master” Control on Leaching and Mobility

Slide 121

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Trace Elements in Coal and Coal

Combustion Residues

 Important for recycling and disposal 

 What factors control trace element leaching and 

mobility?

 How can we characterize the material to 

understand trace element leaching and mobility?
73

Slide 122

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Variety of Leaching Tests

 Toxicity Characteristic Leaching Protocol (TCLP) EPA 

method 1311 using acetic acid with pH = 2.88 or 4.93 

in 18 hour batch tests to simulate disposal in a 

municipal landfill 

 Synthetic Precipitation Leaching Protocol (SPLP) 

Batch and column leaching using solution that 

mimics rainfall and disposal in environment exposed 

to precipitation 

 Other: Deionized water, variety of reagents such as 

ammonium chloride, acetic acid, HCl, H2SO4, HNO3, 

and HF 

Slide 123

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Strategy for Leaching Tests

Determine environment of disposal or use:

e.g. monofill, municipal landfill, mine fill, land 

application and exposure 

Select appropriate leaching protocol:

e.g. TCLP, SPLP, batch, column, short time, 

longer time 

 Apply leaching tests to determine representative 

behavior 
74

Slide 124

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Examples from Multi-source Power Plant

2.5 – 3.5 weighted percent sulfur

Feed coal, bottom ash, fly ash

Precipitator temperature about 130oC 

0.6 – 0.9 weighted percent sulfur

Feed coal, bottom ash, 2 fly ashes

Precipitator temperature about 470oC

2 fly ashes are coarse and fine 

High sulfur furnace

Low sulfur furnace

Slide 125

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Leaching Experiments

18 hour, 20:1 water to solid ratio

< 1 hour, 20:1 water to solid ratio

Column: > 64 flow days, water to solid 

ratio varied
75

Slide 126

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

18-Hour Batch Leach of Fly Ash

High S Low S

Coarse

Low S

Fine

pH Cu Zn As Mo V

Avg 11

% Total

<.0005

<.004

0.13

0.10

0.04

0.47

1.1

48

0.1

0.65

Avg 8.3

% Total

0.13

1.6

0.013

0.29

0.06

4.4

0.30

37

0.15

1.0

Avg 4.6

% Total

4.2

28

0.55

4.3

0.02

0.49

0.099

7.8

0.025

0.13

Averages for elements are in ppm

Slide 127

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

18-Hour Batch Leach of Fly Ash

High S Low S

Coarse

Low S

Fine

pH Al Ca K Na SO

4

Avg 11

% Total

9.4

0.16

310

25

11

1.3

15

6.8

450

66

Avg 8.3

% Total

4.6

0.06

53

13

19

1.8

7.1

4.8

140

77

Avg 4.6

% Total

58

0.73

91

18

110

11

26

14

830

100

Averages for elements are in ppm
76

Slide 128

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

18-Hour Batch Leach of Fly Ash

High S Low S

Coarse

Low S

Fine

pH Al Ca K Na SO

4

Min 9.1

Max

0.24

24

230

420

1.3

25

8.4.

30

220

670

Min 4.7

Max

0.08

10

21

100

9.0

35

2.9

22

74

220

Min 3.3

Max

0.007

170

53

140

15

220

6.5

10

150

1,900

12

10

8.1

Minimum and maximum values for elements are in ppm

Slide 129

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Low Sulfur Coarse Fly Ash

-
77

Slide 130

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

High Sulfur Fly Ash--20:1 Water to Ash Ratio

Slide 131

Fly Ash: From Cradle to Grave, 2007 Clearwater Coal Conference Tutorial

Summary

 Trace element leaching and mobility in coal and 

coal combustion residue depends primarily on pH

 Leaching tests can identify important reactions

 Multiple samples provide best estimate of behavior

 Recent research now provides basis for improved 

understanding of trace element behavior
78

References

Affolter, R.H., and Hatch, J.R., 1995, Cretaceous and Tertiary coals and coal-bearing rocks 

of the western United States; a bibliography of the U.S. Geological Survey data for 

resource estimation, quality determination, and reclamation potential evaluation: U.S. 

Geological Survey Circular 1108, p. 44-45.

Baedecker, P.A., Grossman, J.N., and Buttleman, K.P., 1998, National geochemical data 

base; PLUTO geochemical data base for the United States: U.S. Geological Survey DDS47, CD-ROM.

Bragg, L.J., Oman, J.K., Tewalt, S.J., Oman, C.L., Rega, N.H., Washington, P.M., and 

Finkelman, R.B., 1998, Analytical data, sample locations, descriptive information, 

analytical methods and sampling techniques, database perspective, and bibliographic 

references for selected U.S. coal samples, in U.S. Geological Survey Coal Quality 

(COALQUAL) Database: version 2.0: U.S. Geological Survey Open-File Report 97-134, 

CD-ROM.

Brownfield, M.E., Affolter, R.H., Cathcart, J.D., Rice, C.A., Brownfield, I.K., O'Connor, 

J.T., Zielinski, R.A., Bullock, J.H., Jr., Hower, J.C., and Meeker, G.P., 2005, 

Characterization and modes of occurrence of elements in feed coal and coal combustion 

products from a power plant utilizing low sulfur Powder River basin coal: U.S. 

Geological Survey Scientific Investigations Report 2004-5271, 36 p.

Dragoset, R.A., Musgrove, A., Clark, C.W., and Martin, W.C., 2003, Periodic table atomic 

properties of the elements: Physics Laboratory, National Institute of Standards and 

Technology (NIST), Technology Administration, U.S. Department of Commerce, NIST 

SP 966, poster available at http://physics.nist.gov/PhysRefData/PerTable/index.html.

EERC (Energy and Environmental Research Center), 2006, Mercury in coal and 

transformations in combustion flue gases, in Mercury Control Short Course: EERC, 

September 7, 2006, Denver Airport Marriott at Gateway Park, Denver, Colorado, p. 18.

Ellis, M.S., 1995, Bibliography of publications by members of the Branch of Coal Geology, 

Office of Energy and Marine Geology, U.S. Geological Survey, January 1, 1985-

September 30, 1994: U.S. Geological Survey Open-File Report 95-65, 194 p., 

http://pubs.usgs.gov/of/1995/ofr-95-0065-a/.

Finkelman, A.C., Wong, C.J., Cheng, A.C., Finkelman, R.B., 1991, Bibliography of 

publications containing major, minor, and trace element data from the National Coal 

Resources Data System: U.S. Geological Survey Open-File Report 91-123, 19 p.

Hower, J.C., Trimble, A.S., Eble, C.F., Palmer, C.A., and Kolker, Allan, 1999, 

Characterization of fly ash from low-sulfur and high-sulfur coal sources: partitioning of 

carbon and trace elements with particle size: Energy Sources, v. 21, p. 511-525. 

Hower, J.C., Finkelman, R.B., Rathbone, R.F., and Goodman, J.H., 2000, Intra- and interunit variation in fly ash petrography and mercury adsorption: examples from a western 

Kentucky power station: Energy & Fuels, v. 14, p. 212-216.
79

Hower, J.C., Maroto-Valer, M.M., Taulbee, D.N., Sakulpitkakphon, Tanaporn, 2000, 

Mercury capture by distinct fly ash carbon forms: Energy & Fuels, v. 14, p. 224-226.

Larson, A.C., and Von Dreele, R.B., 1994, General Structure Analysis System (GSAS): Los 

Alamos National Laboratory Report 86-748, 231 p.

Mardon, S.M., and Hower, J.C., 2004, Impact of coal properties on coal combustion byproduct quality: examples from a Kentucky power plant: International Journal of Coal 

Geology, v. 59, p. 153-169.

Maroto-Valer, M.M., Taulbee, D.N., and Hower, J.C., 2001, Characterization of the carbon 

types present in fly ash separated by density gradient centrifugation: Fuel, v. 80, p. 795-

800.

Rubel, A.M., Hower, J.C., Mardon, S.M., and Zimmerer, M.J., 2006, Thermal stability of 

mercury captured by ash: Fuel, v. 85, p. 2509.

Schweinfurth, S.P., 2003, Coal—a complex natural resource; an overview of factors affecting 

coal quality and use in the United States, with a contribution on coal quality and public 

health by Finkelman, R.B.: U.S. Geological Survey Circular 1143, 39 p.

Wood, G.H., Jr., Kehn, T.M., Carter, M.D., and Culbertson, W.C., 1983, Coal resource 

classification system of the U.S. Geological Survey: U.S. Geological Survey Circular 

891, 65 p.

Contact Information

Ronald H. Affolter, Box 25046, MS 939, Denver Federal Center, Denver, Colorado 80225, 

303-236-7752, affolter@usgs.gov

Michael E. Brownfield, Box 25046, MS 939, Denver Federal Center, Denver, Colorado 

80225, 303-236-5742, mbrownfield@usgs.gov

Margaret S. Ellis, Box 25046, MS 939, Denver Federal Center, Denver, Colorado 80225, 

303-236-7775, mellis@usgs.gov

James C. Hower, 2540 Research Park Dr., Lexington, Kentucky 40511, 859-257-0261, 

hower@caer.uky.edu

Jamey D. McCord, Box 25046, MS 939, Denver Federal Center, Denver, Colorado 80225, 

303-236-2460, jdmccord@usgs.gov

Cynthia A. Rice, Box 25046, MS 939, Denver Federal Center, Denver, Colorado 80225, 303-

236-1989, crice@usgs.gov