U.S. Department of Energy
U.S. Environmental
Protection Agency
Assistant Secretary for Energy Technology
Division of Solid Fuel Mining and Preparation
Washington, D.C. 20585
Industrial Environmental
Research Laboratory
Research Triangle Park, N.C. 27711
EPA-600/7-78-038
March 1978
A WASHABILITY AND ANALYTICAL
EVALUATION OF POTENTIAL
POLLUTION FROM
TRACE ELEMENTS IN COAL
Interagency
Energy-Environment
Research and Development
Program Report
z
7_
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
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The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
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This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
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essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
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EPA REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/7-78-038
March 1978
UC-13
A WASHABILITY AND ANALYTICAL
EVALUATION OF POTENTIAL POLLUTION
FROM TRACE ELEMENTS IN COAL
by
J.A. Cavallaro, G.A. Gibbon, and A.W. Deurbrouck
U.S. Department of Energy
Division of Solid Fuel Mining and Preparation
Washington, DC 20585
EPA Interagency Agreement No. OXE685-AJ
Program Element No. EHE623A
EPA Project Officer David A. Kirchgessner
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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DISCLAIMER
This report was prepared as an account of work sponsored by
the United States Government. Neither the United States nor
the United States Department of Energy, nor any of their employees,
makes any warranty, express or implied, or assumes any legal
liability or responsibility for the accuracy, completeness, or a
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial product,
process, or service by trade name, mark, manufacturer, or otherwise,
does not necessarily constitute or imply its endorsement, recommenda-
tion, or favoring by the United States Government or any agency thereof.
The views and opinions of authors expressed herein do not necessarily
state or reflect those of the United States Government or any agency
thereof.
Available from:
National Technical Information Service (NTIS)
U.S. Department of Cotmaerce
5285 Port Royal Road
Springfield, Virginia 22161
Price: Printed Copy: $
Microfiche: $ 3.00
ii
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ABSTRACT
This report presents the results of a washability study showing the trace
element contents of various specific gravity fractions for 10 coal samples
collected from various coal-producing regions of the United States.
Reliable analytical methods were developed to determine cadmium, chromium,
copper, fluorine, mercury, manganese, nickel, and lead in the whole coals and
the various specific gravity fractions of the coals.
The material balances for the 8 trace elements for the 10 coals ranged
from 85 to 115 percent with an average of 99 percent and a 95-percent confi-
dence interval of ±3 percent.
The magnitude of the concentrations of the various trace elements varied
quite a bit from coalbed to coalbed within a region and also from region to
region.
The data from the analytical determinations on the washed coals are
plotted as washability curves so that the quantity and quality of the clean
coal products can be obtained at the desired specific gravity of separation.
Generally, the data showed that most of the trace elements of interest
concentrated in the heavier specific gravity fractions of the coal, indicating
that they are associated with mineral matter; removal of this material should
result in significant trace element reductions, ranging up to 88 percent.
A list of references of other studies of trace elements in coal is
presented.
iii
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CONTENTS
Abstract iii
Figures v
Tables vi
Acknowledgments . viii
Introduction 1
Experimental Work 1
Sample Collection 1
Sample Preparation 1
Gravimetric Testing . 2
Analytical Methods 2
Methods Employed 4
Experimental Results: Washability Data 6
Discussion of Results 14
Northern Appalachian Region Coals 14
Southern Appalachian Region Coals 18
Eastern Midwest Region Coals 18
Western Region Coals 23
Conclusions 7. . 23
References 28
iv
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FIGURES
Number
1 Washability analyses of Pittsburgh bed coal, Allegheny County,
Pa., showing the trace element content at various specific
gravities of separation and clean coal recoveries 15
2 Washability analyses of Waynesburg bed coal, Belmont County,
Ohio, showing the trace element content at various specific
gravities of separation and clean coal recoveries 16
3 Washability analyses of Upper Freeport bed coal, Garrett County,
Md., showing the trace element content at various specific
gravities of separation and clean coal recoveries 17
4 Washability analyses of Hazard No. 4 bed coal, Bell County, Ky.
(East), showing the trace element content at various specific
gravities of separation and clean coal recoveries ....... 19
5 Washability analyses of No. 6 bed coal, Perry County, 111., show-
ing the trace element content at various specific gravities of
separation and clean coal recoveries 20
6 Washability analyses of No. 5 bed coal, Perry County, 111., show-
ing the trace element content at various specific gravities of
separation and clean coal recoveries 21
7 Washability analyses of No. 7 bed coal, Ohio County, Ky. (West),
showing the trace element content at various specific gravities
of separation and clean coal recoveries 22
8 Washability analyses of Red bed coal, Navajo County, Ariz., show-
ing the trace element content at various specific gravities of
separation and clean coal recoveries 24
9 Washability analyses of No. 8 bed coal, San Juan County, N. Hex.,
showing the trace element content at various specific gravities
of separation and clean coal recoveries 25
10 Washability analyses of Rock Springs No. 3 bed coal, Sweetwater
County, Wyo., showing the trace element content at various
specific gravities of separation and clean coal recoveries ... 26
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TABLES
Number Page
1 Analysis of NBS standard reference coals, 1630 and 1632 ...... 3
2 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, Pittsburgh coalbed,
Pennsylvania > 7
3 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, Waynesburg coalbed, Ohio ... 7
4 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, Upper Freeport coalbed,
Maryland 8
5 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, Hazard No. 4 coalbed,
Kentucky (East) 8
6 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, No. 6 coalbed, Illinois ... 9
7 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, No. 5 coalbed, Illinois ... 9
8 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, No. 7 coalbed, Kentucky
(West) 10
9 Washability analyses showing the levels of trace elements in the
sample crushed to 3/8-inch top size, Red coalbed, Arizona .... 10
10 Washability analyses showing the levels of trace elements in the
sample crushed to 3/8-inch top size, No. 8 coalbed, New Mexico . . 11
11 Washability analyses showing the levels of trace elements in the
sample crushed to 14-mesh top size, Rock Springs No. 3 coalbed,
Wyoming 11
vi
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Number Page
12 Summary of composite product analyses by region for coals crushed
to 14-mesh top size and cleaned at 1.60 specific gravity, show-
ing the trace element reduction attainable 12
13 Summary of "product analyses showing the ratio of trace element
concentration of the float 1.60 specific gravity product to
that of the sink 1.60 specific gravity product 13
vii
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ACKNOWLEDGMENTS
This report was made possible by the cooperation and assistance of the
officials of the mines from which the coal samples were collected. The authors
wish to thank those members of the Coal Preparation and Analysis Laboratory of
the U.S. Department of Energy who collected the samples and performed the wash-
ability studies and those members of the Environmental Analysis and Analytical
Chemistry Branches of the Pittsburgh Energy Research Center who performed the
trace element analyses.
The work was funded by the Environmental Protection Agency, and the
authors wish to acknowledge the assistance of T. Kelly Janes and James D.
Kilgroe from the Industrial Environmental Research Laboratory of the Environ-
mental Protection Agency, Research Triangle Park, N.C.
viii
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INTRODUCTION
There is a general awareness that trace elements in coal might contribute
substantial quantities of potentially hazardous materials to the environment.
Most of the 650 million tons of coal mined goes to powerplants where it is
burned. Thus, a coal containing concentrations of only 1 part per million
(ppm) could emit 650 tons per year of a potentially hazardous substance into
the environment.
Certain trace elements may concentrate in particular specific gravity
fractions of the raw coal; those that do, may be removed by conventional
coal-washing processes prior to combustion.
This report discusses (1) the development of reliable analytical methods
for quantifying eight trace elements in raw coals and in their various spe-
cific gravity fractions (During informal discussions with the Environmental
Protection Agency, they provided a list of 17 potentially toxic elements in
coal; this report evaluates 8 of those elements, Cd, Cr, Cu, F, Hg, Mn, Ni,
and Pb, and work is continuing on the remaining 9 elements), (2) the results
of washability analyses performed on selected coals to show the distribution
of the trace elements in the various specific gravity fractions, and (3) the
evaluation of the data to determine if the trace element concentrations of
the coals could be reduced by removal of selected specific gravity increments.
EXPERIMENTAL WORK
Sample Collection
Face samples were collected according to the procedure recommended by
Fieldner and Selvig (10) and Holmes (12), except that the dimensions of each
sample cut were expanded to permit 600 pounds of coal to be taken from the
face. Partings and impurities were not removed from the samples. The samples
were loaded into drums which contained plastic liners and shipped to the
Bureau of Mines coal preparation laboratories at Bruceton, Pa., for analysis.
Sample Preparation
Each 600-pound channel sample was air-dried and then crushed to 1-1/2-inch
top size. The sample was then coned, long-piled, shoveled into four pans, and
divided into two portions by combining opposite pans. One of the portions was
crushed and riffled in several stages until a 3-pound sample of 14-mesh by 0
material was obtained for washability analysis. This procedure was followed
for all samples except those from Arizona and New Mexico. For these samples
the material crushed to 3/8-inch top size was used since the 14-mesh by 0
material had been inadvertently discarded. The sample was then float-sink
-------
tested in gl^ss s.epara.tory vessels at 1.30, 1.40, and 1.60 specific gravities
using CERTIGRAV, a commercial organic liquid; the solution tolerance is
± 0.001 specific gravity unit and was monitored using a spindle hydrometer.
Gravimetric Testing
The sample was placed in the 1.30 specific gravity bath in small quanti-
ties to prevent particle entrapment, stirred, and allowed to separate. The
lighter density coal fraction was removed from the surface of the bath by
vacuum filtration, and the heavier density material which settled to the con-
tainer bottom was also vacuum-filtered. The heavier density material was then
placed in the next higher specific gravity solution, and the process was re-
peated until the sample was separated into the desired specific gravity
fractions.
Upon completion of the float-sink testing, the specific gravity fractions
were air-dried and analyzed for cadmium, chromium, copper, fluorine, mercury,
manganese, nickel, and lead. All results are the average of at least two
chemical analyses.
It should be noted that float-sink separations are based on the specific
gravity of the heterogeneous particles separated. If individual components of
the coal are small enough in size and are physically attached to larger parti'
cles, they will be separated into a specific gravity fraction that is the
average of the weighted specific gravity of the two particles. The finer a
coal is ground, the greater the liberation of the individual constituents
having different specific gravities, and the sharper the separation of these
particles. In coal preparation practice today, most coals are not crushed
finer than about 1-inch top size. Since the tests conducted in this study
were designed to simulate current practice, some of the particles float-sink
tested were not discrete particles of pyrite, rock, or coal. These hetero-
geneous particles lead to what may be interpreted as anomalous results. Al-
though this effect cannot be wholly eliminated, replicate analyses, which were
performed in this study, can help define the trace element content of the
various specific gravity fractions.
The float-sink data from the channel samples are not to be construed as
representing the quality of the product loaded at the mine where the sample was
taken but rather as indicating the quality of the bed in that particular geo-
graphical location. Float-sink data are based upon theoretically perfect
specific gravity separations, which are approached but not equaled in commer-
cial practice.
Analytical Methods
The complex and variable nature of coal makes any reliable chemical analy-
sis difficult. Add to the normal difficulties of coal analysis the many pit-
falls of trace element analysis, and the analyst must exercise extreme care in
order to produce precise and accurate results. The chemical analyses in the
present study were performed using standard coals, material balances, and the
method of standard additions in an effort to produce results that could be
presented with some degree of confidence.
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Contamination; A major concern for an analyst engaged in trace element
analyses is contamination. Additions of extremely small amounts of extraneous
material to a sample may yield erroneous results. The contamination of samples
may occur during storage, handling, or analysis.
Another source of contamination was found to be automobile exhaust pro-
ducts in airborne dust. Lead from these exhaust products will be deposited on
samples left out in the laboratory, particularly if the laboratory is located
near heavily traveled roads.
Mercury is ubiquitous in most laboratories and will contaminate samples
or equipment left out in the laboratory for any length of time. Mercury vapor
is also present in tanks of laboratory gases but can be eliminated by the use
of a charcoal filter in lines carrying the gases.
Many contamination problems can be eliminated by proper precautions if
one is aware of their presence. Others must be accounted for in blank cor-
rections with a resultant loss of precision.
Losses; Another source of error in trace element analysis is loss of the
analyte through contact with an adsorbing surface. An interesting example of
this "negative contamination" was observed with the use of "nonwetting" plati-
num crucibles that were tested for use in the lithium metaborate fusion pro-
cedure described below. The use of these crucibles, which are fabricated of
a platinum-5 percent gold alloy, results in serious loss of trace copper. The
results of a series of tests with these crucibles showed that the concentra-
tion of copper in the lithium metaborate was reduced from 16 ± 3 ug Cu/g to
4 ± 1 ug Cu/g when the lithium metaborate was fused in the "nonwetting" cruci-
bles. No loss was observed when the lithium metaborate was fused in standard
platinum crucibles.
Analysis of Standard Coals; The National Bureau of Standards has certi-
fied two coals for trace element content. SRM 1630 is certified for mercury,
and SRM 1632 is certified for 14 trace elements. The trace element concentra-
tions for the standard coals as determined in this laboratory are shown in
table 1.
TABLE 1. - Analysis of NBS Standard Reference Coals, 1630 and 1632
SRM No. Element Certified value (ppm)1 Determined value (ppm)2
1630
1632
1632
1632
1632
1632
1632
1632
Mercury
Mercury
Cadium
Lead
Nickel
Copper
Chromium
Manganese
0.126 ± 0.006
0.12 ± 0.02
0.19 ± 0.03
30 ± 9
15 ± 1
18 ± 2
20.2 ± 0.5
40 ± 3
0.125 ± 0.014
0.10 ± 0.01
0.17 ± 0.02
28 ± 3
15 ± 2
16.7 ± 0.6
20.1 ± 0.6
45.8 ± 0.8
Statistic defined by NBS as " ... in no case less than the 95 percent
confidence limits computed for the analyses."
21 standard deviation.
-------
Neither of the NBS standard coals was certified for fluorine so SKM 56b,
a phosphate rock containing 3.4 percent fluorine, was used as the standard.
The fluorine content was found to be 3.3 percent ± 0.1 percent.
Material Balances: The study of float-sink fractions affords an addi-
tional check on the analytical methods; namely, material balances. For each
element studied, the sum of the trace element content found in the various
specific gravity fractions should agree with the trace element content found
in the starting coal. Having no objective guidelines at the start of this
work, a rejection criterion of ±15 percent was arbitrarily set on the material
balance for each element. Thus, if a material balance did not fall between
85 percent and 115 percent for an element in a coal, the analyses were
repeated.
After processing all 10 coals, the average material balance was calculated
to be 99 percent with a 95-percent confidence interval of ±3 percent. The
average was calculated by including all material balances regardless of their
value, provided no objective reason was known for their rejection. An example
of an objective reason for rejection would be known contamination of a sample.
Method of Standard Additions; As mentioned earlier, the analysis of coals
is difficult owing to their nonuniformity. The nonuniformity of samples is
even greater in the float-sink fractions, where each fraction is chemically
quite different from all the others. No single standard material can be de-
vised to represent the varying chemical matrix in a series of float-sink
samples. To overcome this difficulty, the method of standard additions was
employed in all the analyses except for the determination of mercury and
fluorine, where isolation of the analyte element from the sample matrix is
part of the experimental method.
The method of standard additions overcomes matrix effects by utilizing
the sample itself as the standard. This is accomplished by splitting the
sample solution into four equal parts. Known amounts of the element of inter-
est are added to three of the sample aliquots. The additions are contained in
volumes that are small compared with the total volume of the sample solution,
so that dilution of the sample solution is negligible. When the four solu-
tions are analyzed, the absorption is plotted as the ordinate and the amount of
analyte added to each solution is plotted as the abscissa. The result should
be a straight line with a negative intercept. The magnitude of the intercept
is equal to the amount of analyte present in the original sample solution. In
practice, the plotting is accomplished on a programmable desk calculator using
a linear regression by the method of least squares.
Methods Employed
As the details of the analytical methods employed in this study will be
published separately, the descriptions to follow will only outline the
procedures.
Mercury? Mercury was determined by a double gold amalgamation-atomic
absorption procedure that has been described previously (£, 19).
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During this study it was discovered that several of the sink 1.60 samples
derived from high-sulfur coals produced H2S04 when combusted in oxygen. The
sulfuric acid tended to coat the gold wire used in the amalgamators, resulting
in loss of sensitivity. To overcome this difficulty, a modified procedure was
adopted in which a nitrogen pyrolysis method was used to analyze samples that
when burned in oxygen caused a loss of sensitivity due to the formation of
H2S04. The sample was pyrolyzed in a nitrogen stream, and the resultant gases
were burned in an oxygen atmosphere. After oxidation, the gases were processed
in the same manner as the gases that were produced by burning coal in an oxygen
stream.
Fluorine; A number of methods are reported in the literature for the
determination of fluorine in coal (2_, 5_, J3, 15). Most of them involve the
bleaching action of fluoride ion on a colored complex. The methods are sub-
ject to numerous interferences, and generally the colored complexes are not
stable for appreciable amounts of time. The method employed in this study
utilizes a fluoride-ion-specific electrode, which is simpler and faster to use
and is not as subject to interferences as were the methods used in the past.
A 2-gram coal sample was mixed with 0.8 gram of CaO in a platinum crucible
and ashed at 600° C until all carbonaceous matter was oxidized. The residue
was fused with 4 grams of Na2C03. The fusion cake was leached with phosphoric
acid, and the fluorine was distilled from a phosphoric acid-sulfuric acid
mixture at 135° C. The distillate was made basic to phenolphthalein with
1 percent sodium carbonate solution and evaporated to about 5 ml. The solu-
tion was neutralized with 1:1 I^SO^ using methyl orange as an indicator. Ten
milliliters of a commercial fluoride-ion-electrode buffer was added, and the
volume was adjusted to 25 ml with distilled deionized water. The solution
was transferred to a plastic beaker, and the potential measurements were made
on an expanded-scale pH meter.
At fluoride concentrations below 10 molar, the electrode response does
not follow the Nernst relationship (that is, the electrode response is not
linearly related to the logarithm of the fluoride concentration), and it be-
comes necessary to add a known quantity of fluoride to the solution in order
to bring the concentration into the linear range of electrode response. After
the concentration of fluoride in the solution has been determined, the fluoride
addition that has been made is subtracted; the difference is the fluoride ion
concentration in the solution from the sample.
Cadmium and Lead: Cadmium is normally present in coal at concentrations
well below 1 ppm, and while lead concentrations can run much higher, the atomic
absorption sensitivity for an aqueous solution of lead is only about 0.5 ug/ml
for 1 percent absorption. Solvent extraction offers a means for increasing the
sensitivity of the determinations by isolation and concentration of the metals
of interest. A procedure was developed utilizing the extraction of the iodide
complexes of lead and cadmium into methylisobutylketone (MIBK) (13).
A 10-gram sample of coal (or a 5-gram sample of the sink 1.60 fraction)
was weighed into a Vycor or platinum dish and placed in a cold muffle furnace.
The temperature was raised to 500° C in 1 hour, and ashing continued at that
temperature for about 16 hours. Tests in this and other laboratories (3_, 17)
showed no significant loss at this temperature for the trace metals investiga-
ted. The resulting ash was digested in concentrated HCl and filtered, and
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the insoluble residue was again ashed at 500° C. After treatment with HF and
H2S04 to volatilize silica, the sample was again leached with HC1 and filtered.
The residue after ignition was fused in potassium carbonate, the fusion cake
was dissolved in dilute HC1, the resulting solution was added to the combined
filtrates, and the solution was evaporated to near dryness. The residue was
dissolved in HC1, transferred to a volumetric flask, and diluted to volume.
Aliquots were taken, and standard additions of lead and cadmium were made.
Ascorbic acid, potassium iodide, and MIBK were added, and the lead and cadmium
iodides were extracted into the MIBK. The ketone layer was aspirated into the
flame of an atomic absorption spectrophotometer. Methyl isobutyl ketone was
used to establish a base line. The amount of analyte present was calculated
by means of a linear least squares regression procedure.
Chromium. Copper, Manganese, and Nickel; The procedure used for the
preparation of coal samples for the determination of Cr, Cu, Mn, and Ni was
similar to that used for the preparation of coal samples for Cd and Pb deter-
minations. A 2-gram sample of coal (or a 1-gram sample of the sink 1.60
fraction) was ashed at 500° C in a platinum crucible, and the ash was then
treated with H2S04 and HF to volatilize the silica. After evaporation, the
residue was leached with concentrated HC1 and filtered. If considerable
residue remained, it was again treated with HF and leached with HC1. Finally
the insoluble portion was fused at 950° C with LUB02- The fusion cake, after
cooling, was dissolved in 3 N HC1, and the solution was combined with the
filtrates. The solution was transferred to a 100 ml volumetric flask and
diluted to volume. Three 25 ml aliquots were taken, and additions of stand-
ards were made to each aliquot. As was done with the lead and cadmium deter-
minations, a linear least squares regression was used to calculate the con-
centration of analyte present.
EXPERIMENTAL RESULTS: WASHABILITY DATA
Ten sets of individual washability data were compiled to show the fate of
the various trace elements in the coals tested upon crushing to 14-mesh top
size and subsequent specific gravity fractionation (tables 2 through 11).
Three samples each were evaluated from the Northern Appalachian Region, the
Eastern Midwest Region, and the Western Region; one sample from the Southern
Appalachian Region was also evaluated.
Each set of washability data shows the direct and cumulative weight-
percents of each specific gravity fraction and the trace element contents of
each fraction in parts per million. The trace element contents of the head
sample are also shown for comparative purposes with the composite washability
analyses
Generally, the magnitude of the various trace element content levels, as
determined in the whole coals from the various regions, were comparable to
those as determined by R. R. Ruch et al. CIS). A summary of composite product
analyses by region is presented in table 12.
Table 13 is a summary of the product analyses expressing the trace element
content as a ratio of the trace element concentration of the float 1.60 spe-
cific gravity product to the trace element concentration of the sink 1.60
specific gravity product:
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TABLE 2. - Washability analyses showing the levels of trace elements in the sample
crushed to 14-mesh top size, Pittsburgh coalbed,
Direct
Product
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
percent
59.4
29.3
5.9
5.4
-
Parts per million
Cd
0.03
.09
.35
.39
-
Cr Cu
11 4.6
19 6.7
31 19
43 43
_ »
F Hg
17 0.08
33 .09
81 .28
125 1.7
-
Mn Ni
2.8 7.4
5.9 10
19 15
150 30
- -
Pb
1.7
3.9
13
26
-
Weight,
percent
59.4
88.7
94.6
100.0
100.0
P ennsy Ivania
Cumulative
Parts per million
Cd
0.03
.05
.07
.09
.09
Cr Cu F
11 4.6 17
14 5.2 22
15 6.1 26
16 8.1 31
16 9.0 35
Hg Mn
0.08 2.8
.08 3.8
.10 4.8
.18 13
.19 11
Ni Pb
7.4 1.7
8.2 2.4
8.7 3.1
9.8 4.3
11 4.3
Cd «* cadmium, Cr = chromium, Cu
Pb - lead.
copper, F - fluorine, Hg = mercury, Mn = manganese, Ni = nickel, and
TABLE 3. - Washability analyses showing the levels of trace elements in the sample
crushed to 14-mesh top
size,
Waynesburg coalbed, Ohio
Direct
Product
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
percent
23.4
40.7
20.6
15.3
-
Parts per million
Cd Cr
0.14 15
.06 18
.15 24
.36 30
_
Cu F
6.1 27
5.6 53
10 113
41 146
-
Hg Mn
0.13 4.3
.07 8.2
.15 20
.61 66
-
Ni
8.1
9.6
12
41
-
Pb
2.1
2.4
5.6
26
-
Weight,
percent
23.4
64.1
84.7
100.0
100.0
Cumulative
Parts per million
Cd Cr
0.14 15
.09 17
.10 19
.14 20
.14 21
Cu F
6.1 27
5.8 44
6.8 60
12 73
11 78
Hg Mn
0.13 4.3
.09 6.8
.10 10
.18 19
.18 18
Ni Pb
8.1 2.1
9.0 2.3
9.8 3.1
15 6.6
16 6.7
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TABLE 4. - Washability analyses showing the levels of trace elements in the sample
crushed to 14-mesh top size, Upper Freeport coalbed, Maryland
Direct
Product
Float-1.30
1.30 -1.40
1.4Q -1.60
Sink -1.60
Head sample
Weight,
percent
37.6
36.7
10.3
15.4
-
Parts per million
Cd Cr
0.07 13
.06 23
.20 34
.25 73
-
Cu
7.0
8.8
24
58
-
F
8
43
80
1279
-
Hg Mn
0.08 2.5
.16 6.5
.56 23
1.13 51
-
Ni
8.1
9.2
26
38
-
Pb
0.8
2.6
9.2
36
-
Weight,
percent
37.6
74.3
84.6
100.0
100.0
Cumulative
Parts per million
Cd Cr
0.07 13
.06 18
.08 20
.10 28
.10 27
Cu
7.0
7.9
9.8
17
16
F He Mn Ni Pb
*
8 0.08 2.5 8.1 0,8
25 .12 4.5 8.6 1.7
32 .17 6.7 11 2.6
170 .32 14 15 7.7
70 .28 13 16 6.5
1Insufficient sample; however, this number was calculated by compositing the other fractions and making a
material balance.
00
TABLE 5. - Washability analyses showing the levels of trace elements in the sample
crushed
to 14-mesh
top size, Hazard
No. 4 coalbed
, Kentucky (East)
Direct
Weight,
Product percent Cd
Float-1.30 51.0 0.08
1.30 -1.40 16.9 .20
1.40 -1.60 9.2 .24
Sink -1.60 22.9 .10
Head sample
Parts per million
Cr
6
11
33
73
-
Cu
13
26
55
66
-
F
11
26
110
400
-
Hg
0.04
.07
'.12
.22
-
Mn
30
89
240
1,100
-
Ni
10
15
28
38
-
Pb
3.5
9.7
25
40
**';,' .
Weight,
percent
51.0
67.9
77.1
100.0
100,0
Cumulative
Parts per million
Cd
0.08
.11
.12
.12
.12
Cr
6
7
10
25
26
Cu
13
16
21
31
28
F
11
15
26
112
110
Hg
0.04
.05
.06
.09
.09
Mn
30
45
68
300
260
Ni
10
11
13
19
18
Pb
3.5
5.0
7.4
15
14
-------
TABLE 6. - Washability analyses showing the levels of trace elements in the sample
crushed to 14-mesh top size, No. 6 coalbed,
Product
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
Direct
Parts per million
percent Cd
44.1
29.5
13.9
12.5
-
TABLE 7.
Product
»
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
percent
49.3
31.8
12.1
6.8
-
0.00
.01
.09
5.00
-
Cr
10
17
19
29
-
Cu F
2.7 40
6.4 75
9.4 120
26 150
-
Hg Mn
0.06 8.4
.08 14
.12 22
.15 230
_ _
- Washability analyses showing
crushed
Direct
to 14-mesh
Ni
11
18
22
26
the
top
Parts per million
Cd
0.02
.06
.16
4.3
-
Cr
8.
14
13
6.
-
Cu F
5 4.6 18
7.0 39
11 72
0 18 63
-
Hg Mn
0.06 9
.04 15
.04 41
.09 1,100
-
Ni
7.
6.
10
1.
-
Weight,
Illinois
Cumulative
Parts per
million
Pb percent Cd Cr Cu F Hg Mn
2.4 44.1 0.
8.2 73.6
13 87.5
40 100.0
100.0
00 10 2.7 40 0
00 13 4.2 52
02 14 5.0 65
64 16 7.6 76
61 16 8.6 78
.06 8.4
.07 11
.08 12
.09 39
.09 37
Ni
11
13
15
16
18
Pb
2.4
4.7
6.0
10
9.5
levels of trace elements in the sample
size, No. 5 coalbed
Weight,
Pb percent
4 2.3 49.3 0
9 3.4 81.1
3.7 93.2
1 6.0 100.0
100.0
, Illinois
Cumulative
Parts per
Cd Cr Cu F
.02 8.5 4.6 18
.04 11 5.5 26
.05 11 6.2 32
.34 11 7.0 34
.33 12 6.3 37
million
Hg Mn
0.06 9
.06 11
.05 15
.06 88
.06 89
Ni
7.4
7.2
7.6
7.1
8.2
Pb
2.3
2.7
2.8
3.1
3.0
-------
TABLE 8< - Washability analyses showing the levels of trace elements in the sample
crushed to 14-mesh top
size, No.
7 coalbed, Kentucky (West)
Direct
product
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
percent
Parts per million
Cd Cr Cu F
Hg Mn
Ni Pb
38.7 0.01 5.8 1.6 32 0.06 6,2 4.9 1.0
39.8 .03 8.8 4.4 48 .09 11 6.6 2.7
15.1 .06 13 7.9 91 .19 21 9.2 5.1
6.4 .29 20 13 100 .55 47 7.6 17
TABLE 9. - Washability
Weight,
percent
38.7
78.5
93.6
100.0
100.0
Cumulative
Parts per million
Cd Cr Cu F Hg Mn Ni Pb
0.01 5.8 1.6 32 0.06 6.2 4.9*1.0
.02 7.3 3.0 40 .07 11 5.8 1.9
.03 8.2 3.8 48 .09 11 6.3 2.4
.04 9.0 4.4 52 .12 13 6.4 3.3
.06 9.6 5.0 57 .13 15 6.6 3.7
analyses showing the levels of trace elements in the sample
crushed to 3/8-inch top size, Red coalbed, Arizona
Direct
Product
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
percent
53.6
35.6
6.6
4.2
Parts per
Cd
0.05
.07
.07
.18
Cr
2.2
4.2
10
10
Cu
2.0
4.9
13
15
F
11
21
41
86
million
Hg Mn
0.03 13
.04 14
.03 22
.08 26
Ni
3.1
2.9
3.3
4.0
Pb
2.7
5.5
14
21
Weight,
percent
53.6
89.2
95.8
100.0
100.0
Cumulative
Parts per million
Cd Cr Cu F Hg Mn Ni
0.05 2.2 2.0 11 0.03 13 3.1
.06 3.0 3.2 15 .03 13 3.0
.06 3.5 3.8 17 .03 14 3.0
.06 3.8 4.3 20 .04 14 3.1
.07 3.7 4.8 21 .04 14 3.0
Pb
2.7
3.8
4.5
"5.2
5.8
-------
TABLE 10. - Waahability analyses showing the levels of trace elements in the sample
crushed to 3/8-inch top size, No. 8 coalbed, New Mexico
Product
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
percent
31.2
31.2
19.6
18.0
-
TABLE 11.
Product
Float-1.30
1.30 -1.40
1.40 -1.60
Sink -1.60
Head sample
Weight,
percent
60.7
24.1
9.6
5.6
-
Direct
Parts j>er million
Cd Cr Cu F Hg Mn Ni Pb
0.03 3.8 8.2 46 0.03 15 3.2 3.4
.03 4.9 13 35 .04 18 3.8 7.8
.09 6.7 16 40 .05 37 3.3 13
.27 3.2 25 110 .18 330 2.7 26
Weight,
percent
31.2
62.4
82.0
100.0
100.0
- Washability analyses showing the levels of trace
crushed to 14-mesh top size, Rock
Direct
Parts per million
Cd Cr Cu F Hg Mn Ni Pb
0.06 0.85 3.6 33 0.05 14 3.9 1.9
.13 3.7 4.5 46 .08 14 5.9 4.1
.61 8.3 9.4 64 .06 18 15 10
.61 8.5 7.9 180 .19 540 13 34
--------
Springs No.
Weight ,
percent
60.7
84.8
94.4
100.0
100.0
Cumulative
Parts per million
Cd Cr Cu F Hg Mn Ni Pb
0.03 3.8 8.2 46 0.03 15 3.2 3.4
.03 4.4 11 40 .04 16 3.5 5.6
.04 4.9 12 40 .04 21 3.4 7.4
.08 4.6 14 53 .06 77 3.3 11
.08 5.0 13 52 .07 88 3.4 12
elements in the sample
3 coalbed, Wyoming
Cumulative
Parts per million
Cd Cr Cu F Hg Mn Ni Pb
0.06 0.85 3.6 33 0.05 14 3.9 1.9
.08 1.7 3.9 37 .06 14 4.5 2.5
.13 2.3 4.4 39 .06 14 5.5 3.3
.16 2.7 4.6 47 .07 44 6.0 5.0
.15 3.1 4.3 51 .07 47 5.2 4.7
-------
TABLE 12. - Summary of composite product analyses by region for
coals crushed to 14-mesh top size and cleaned
at 1.60 specific gravity, showing the trace
Product
element reduction attainable
Cumulative analyses
Yield, Parts per million
percent Cd Cr. Cu F Hg
Mn
Ni
Pb
Northern Appalachian Region
Finaf- 1 fin i_
Composite washability-
Reduction, percent
88 0.08 18 8 39 0.12
100 .11 21 12 58 .23
27 14 33 33 48
7
12
42
10
13
23
2.9
6.2
53
Southern Appalachian Region
Float 1.60
Composite washability-
Reduction, percent
77 0.12 10 21 26 0.06
100 .12 25 31 110 .09
0 60 32 77 33
68
300
77
13
19
32
8
15
47
Eastern Midwest Region
Fln-n- 1 fin.- ____.___
Composite washability-
Reduction, percent
91 0.03 11 5 48 0.07
100 .34 12 6.3 54 .09
88 8 21 11 22
13
47
72
9.6
9.8
2
3.7
5.6
34
Western Region
Plnaf- 1 fin -ru-
Composite washability-
Reduction, percent
91 0.07 3.6 6.7 32 0.04
100 .10 3.7 7.6 40 .06
30 3 12 20 33
16
45
64
4.0
4.1
2
5.1
7.1
28
12
-------
TABLE
Product
13. - Summary of product analyses showing the ratio*
of trace element concentration of the float
1.60 specific gravity product to that of
the sink 1.60 specific gravity product
Ratios
Cd Cr Cu F Hg Mn Ni
Pb
Float 1.60
Sink 1.60--
Float 1.60
Sink 1.60
Northern Appalachian Region
10
Southern Appalachian Region
15
13
Eastern Midwest Region
Float 1.60
Sink 1.60
320
Western Region
Float 1.60
Sink 1.60
,
/
/
/
,
/
,
'
19
llt should be
only trace
noted that the ratio does not reflect weight balances but
element concentrations in each fraction.
13
-------
(trace element concentration of float 1.60 specific gravity product)
(trace element concjentration of sink 1.60 specific gravity product)
These are interesting numbers because the samples tested were raw coal channel
samples and therefore did not include any roof or floor material. The yields
of sink 1.60 specific gravity product (refuse material) for the four regions
tested averaged 12, 23, 9, and 9 percent. Under normal mining conditions, on
the average, 25 percent of the mined raw coal will report to the sink 1.60
specific gravity product. Thus using this criterion and assuming that the
trace element content of the roof and floor material would be in the same
concentration as in the sink 1.60 specific gravity material in the raw coal
channel sample, it can be seen that the percent of trace element reduction
would be greater than that shown for the coals tested in the four regions.
DISCUSSION OF RESULTS
Northern Appalachian Region Coals
Three coalbed samples collected from Pennsylvania (1)> Ohio (1), and
Maryland (1) were evaluated; the washability data are presented in tables 2
through 4 and plotted in figures 1 through 3. The trace element contents of
the composite washability samples of the region averaged 0.11 ppm cadmium,
21 ppm chromium, 12 ppm copper, 58 ppm fluorine, 0.23 ppm mercury, 12 ppm
manganese, 13 ppm nickel, and 6.2 ppm lead.
The washability data show that most of these trace elements concentrate
in the heavier specific gravity fractions, which indicates that they are
associated with the inorganic matter. Therefore, crushing the coal to 14-mesh
top size and removing the sink 1.60 specific gravity material would provide
significant trace element reductions ranging up to 53 percent (summary
table 12).
The ratios in table 13 show that the trace element concentrations of the
sink 1.60 specific gravity material were greater by factors ranging from 3 to
13, compared with those of the float 1.60 specific gravity material.
Figure 1 plots the washability data for the Pittsburgh bed coal sample
collected from Pennsylvania. The curves show that generally significant trace
element rejection would occur at a specific gravity of separation of about
1.40 with a clean coal recovery1 of 88 percent.
Figure 2 plots the washability data for the Waynesburg bed coal sample
collected from Ohio. The curves show that even though the cadmium and mercury
contents showed a high concentration in the 1.30 specific gravity fraction,
generally significant trace element reduction would occur at a specific
gravity of separation of 1.60 with a clean coal recovery of 85 percent.
Figure 3 plots the washability data for the Upper Freeport bed coal sample
collected from Maryland. The curves show that significant trace element re-
ductions would occur at a specific gravity of separation of 1.60 with an at-
tendant clean coal recovery of 85 percent. Generally, the range of the trace
element contents varied considerably for the three coals tested.
All recoveries are weight percent.
14
-------
i
8
3
Ul
I
I
Z
o
0.10
.04 r.
.02
1.30 1.40 1.60 Totol
SPECIFIC GRAVITY
OF SEPARATION
jj
S
\
\
i ii
GOPPER
*>*
N
N
S
S
\
\
*
*
\
\
\
x
\
\
f.
/
X
s
s
s
\
S
s
s
20
15
10
5
n
:
*j
\
N
S
>»
i i
CHROMIUM
x-
S,
\
\
s
\
i
s
\
\
S
\
\
^
\
S
s
s
s
*,
1
50 60 70 60 90 100
CUMULATIVE COAL
RECOVERY, percent
i i
LEAD
.15
.10
.05
1.30 1.40 1.60 Totol
SPECIFIC GRAVITY
OF SEPARATION
i i i i i
Ib
10
5
n
i i
_ NICKEL
5
\
I
\
\
\
1
1
T 1 I
I I I I I
16
12
8
n
i i i
_ t
MANGANESE /
/
/
*-,
i i
X
^
^
LN
i
\
\
\
s
N
s,
_
_
1
i i I I r
i I I I I
1
A
/
MERCURY /
y
' r*
^
\
S
\
\
\
1
\
\
\
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1
\
\
s
s
\
\
\
-
"
~
1
I I I I
I I I I I
50 6O 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
FIGURE 1. - Washability analyses of Pittsburgh bed coal, Allegheny County, Pa.,
showing the trace element content at various specific gravities of
separation and clean coal recoveries.
-------
100
80
60
40
20
n
i i i i i
- FLUORINE
^-
-jf
/
x]
.*-
\
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s
V
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E__
S
\
s
s
s
'
s
s
\
\
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-
-
-
-
1
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
16
12
8
4
n
i i i i i
- COPPER '
/
* j
\
\
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\,
l
S
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N
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-
20
15
10
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r>
CHROMIUM-
^
\
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N
\
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\
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l\
k
\
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r\i
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i
.15
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.05
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\
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CADMIUM
\
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l
*
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-
I I I
1111
1 I 1 1 I
0 20 40 60 80 100
CUMULATIVE COAL
RECOVERY, percent
LEAD
.20
.15
.10
.05
- MERCURY
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
16
'2
8
4
n
NICKEL
x
N
S
\
S
^**
S
\
N
S
S,
/
/
\
N
S
S
\
\
S
\
S
\
\
-
-
I I I
1 I I I
i r
i i i ii
0 20 40 60 80 100
CUMULATIVE COAL
RECOVERY, percent
FIGURE 2. - Washability analyses of Waynesburg bed coal, Belmont County,
Ohio, showing the trace element content at various specific
gravities of separation and clean coal recoveries.
-------
I
Q.
80
60
40
20
n
i i i
FLUORINE /
rC 1
\
\
\
\
\
\
s,
1
1
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
Id
_J
\
\
W *nr-
< 30
H 20
£
1 '°
4 o
\
\
t
I
\
s
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s
M
1
CHROMIUM s'
\
i1
3
;
s
\
\
\
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1
.12
.08
.04
,0
i i
CADMIUM
^q ^1
1
\
\
s
1
*
\
\
\
\
\
\
\
\
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1
|
J I L
20 40 60 80 100
CUMULATIVE COAL
RECOVERY, percent
8
6
4
2
n
1 ' ' /
/
LEAD /
/
/
/
|
/
k
\
\
t
t
/
\
\
\
S
\
s,
-
1
"ir
0 20 40 60 80 100
CUMULATIVE COAL
RECOVERY, percent
FIGURE 3. - Washability analyses of Upper Freeport bed coal, Garrett County,
Md., showing the trace element content at various specific
gravities of separation and clean coal recoveries.
-------
Southern Appalachian Region Coals
A sample of Hazard No. 4 bed coal from East Kentucky was evaluated, and
the washability data are presented in table 5 and plotted in figure 4. The
trace element contents of the composite washability sample analyzed 0.12 ppm
cadmium, 25 ppm chromium, 31 ppm copper, 112 ppm fluorine, 0.09 ppm mercury,
300 ppm manganese, 19 ppm nickel, and 15 ppm lead*
The washability data again show that all of the trace elements concen-
trated in the heavier specific gravity fractions, which indicates that they
are associated with the inorganic matter. Therefore, crushing the coal to
14-mesh top size and removing the sink 1.60 specific gravity material would
provide trace element reductions ranging up to 77 percent.
The ratios in table 13 show that except for the cadmium content, which
was the same in both specific gravity fractions, the other concentrations
would be greater in the sink 1.60 specific gravity fraction by factors ranging
from 3 to 16.
Figure 4 plots the washability data for the Hazard No. 4 bed coal sample
collected from East Kentucky. The curves show that significant and feasible
trace element reductions would occur at a specific gravity of separation of
1.60 for all elements except cadmium; the clean coal yield would be 77 percent.
Eastern Midwest Region Coals
Three coalbed samples collected from Illinois (2) and West Kentucky (1)
were evaluated with washability data presented in tables 6 through 8. The
trace element contents of the composite washability samples of the region
averaged 0.34 ppm cadmium, 12 ppm chromium, 6.3 ppm copper, 54 ppm fluorine,
0.09 ppm mercury, 47 ppm manganese, 9.8 ppm nickel, and 5.6 ppm lead.
The washability data show that most of these trace elements concentrate
in the heavier specific gravity fractions, which indicates that they are
associated with the inorganic matter. Therefore, crushing to 14-mesh top
size and removing the sink 1.60 specific gravity material would generally pro-
vide significant trace element reductions ranging up to 88 percent.
The ratios in table 13 show that except for the nickel content, which
was the same in both specific gravity fractions, the ratios would be greater
in the sink 1.60 specific gravity fraction by factors ranging from 2 to 320.
Figures 5, 6, and 7 plot the washability data for the coalbed samples
collected from the No. 6 bed, Illinois, the No. 5 bed, Illinois, and the No. 7
bed, Kentucky (West), respectively. The curves show that generally signifi-
cant trace element reductions would occur at a specific gravity of 1.60 with
clean coal recoveries ranging up to 94 percent.
Generally the range of the trace element contents varied considerably for
the three coals tested, especially the cadmium content, which ranged from
0.04 to 0.64 ppm, and the manganese content, which ranged from 13 to 88 ppm.
18
-------
H
vo
120
100
80
60
40
20
n
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i
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FLUORINE ,'
- * i
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40
30
20
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20,
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IUM
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-
-
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
50 60 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
.02
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
20
15
IO
5
n
1 ' ' /
NICKEL /
_ 1
t**;
N
\
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,~-
^
>s
I
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1
400
300
200
100
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l i 1 1 i
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c^TT"! lol
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-
-
-
i
i i I I
I I I
\ I I
50 60 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
FIGURE 4. - Washability analyses of Hazard No. 4 bed coal, Bell County,
Ky. (East), showing the trace element content at various
specific gravities of separation and clean coal recoveries.
-------
I
8
i
Hi
Id
Ul
I
0.60
.60
.40
.20
1.30 1.40 1.60 Totol
SPECIFIC GRAVITY
OF SEPARATION
I I
20
\S
10
5
n
l l
1 1
_ CHROMIUM ,.
^
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i i
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i i i
40 50 60 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
10
8
4
2
18
16
12
8
4
40
30
20
IU
n
-
/
3
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\
\
\
S
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1
-
-
1
i i i
_ NICKEL rf
-------
H
UJ
O
O
HI
Z
UJ
UJ
o
o
Q40
.20
8
6
4
n
i i i i i
COPPER
^\^
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\
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IS
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I
rf
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-
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I I I I
I I
i i i
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_ /
1
i
!
?«"T^""i k^l
\
N
\
\
S
\
i
_
i
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
40 50 6O 70 80 9O 100
CUMULATIVE COAL
RECOVERY, percent
4
3
2
1
n
i i i i i
LEAD
^
\
s
\
*f
fl
\
s
\
s
s
^
\
s
\
X,
N
s'
N
\
10
0.10
.05
1.30 1.40
1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
i i ii i i
NICKEL
*\
\
N
S
S
\
\
\
\
S
\
x
\
\
\
\
S
S
1
\
\
\
\
\
i
i
I I I I I I
100
80
60
40
20
n
i i i i i
- MANGANESE ,
/
r
- /
/
/
- '
t
i
i
f^t f'vl
o k i I rSJ
's
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_
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i
i i
t i
MERCURY
^
s
s
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MI
\
\
\
^
^.
<\
\
\
\
.'
N
\
\
\
V,
1
I
40 50 60 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
FIGURE 6. - Washability analyses of No. 5 bed coal, Ferry County, 111., showing the
trace element content at various specific gravities of separation and
clean coal recoveries.
-------
N3
80
60
40
20
c n
e v
2 5
I^J *
8 3
1-
Z 2
ui
Ul '
" 0
-
i
ii ii
FLUORINE
^*
^:
\
\
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.
1
A
S
\
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V
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/
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s
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ui 8
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3
" .04
.03
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0
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I
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1 1 1 ,'
COPPER /
S 1
/
Z
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1
\
\
\
\
\
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s
1
-
1
II II
CHROMIUM _-«
₯1
i k i
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\
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CADMIUM ,'
^\
/
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\
\
s
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SL
1
~
-
-
1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
I T I
I
I I
I
0 20 40 60 80 100
CUMULATIVE COAL
RECOVERY, percent
k
\
\
\
s,
1 1 1 1
NICKEL
s*
\
\
\
\
\
\
\
\
\
\
\
s
\
\
\
\
\
s
-
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
16
12
8
4
n
'
Mt
r
INGANESE
\
\
\
1
\
\
\
\
\
\
\
\
\
1
1
I
20 40 60 80 100
CUMULATIVE COAL
RECOVERY, percent
FIGURE 7. - Washability analyses of No. 7 bed coal, Ohio County, Ky. (West),
showing the trace element content at various specific gravities
of separation and clean coal recoveries.
-------
Western Region Coals
Three coalbed samples collected from Arizona (1), New Mexico (1), and
Wyoming (1) were evaluated with washability data presented in tables 9 through
11 and plotted in figures 8 through 10. The trace element contents of the
composite washability samples of the region averaged 0.10 ppm cadmium, 3.7 ppm
chromium, 7.6 ppm copper, 40 ppm fluorine, 0.06 ppm mercury, 45 ppm manganese,
4.1 ppm nickel, and 7.1 ppm lead.
The composite washability data show that most of the trace elements con-
centrated in the heavier specific gravity fractions. Therefore, removing the
sink 1.60 specific gravity material would provide significant trace element
reductions ranging up to 64 percent.
Table 13 shows that the trace element concentrations were greater in the
sink 1.60 specific gravity fraction by factors ranging from 2 to 19.
Figures 8, 9, and 10 plot the washability data for the coalbed samples
collected from the Red bed, Arizona, the No. 8 bed, New Mexico, and the Rock
Springs No. 3 bed, Wyoming. The curves show that generally significant trace
element reductions would occur at a specific gravity of separation of 1.40 at
clean coal recoveries ranging up to 89 percent for the coals from Arizona and
Wyoming, compared with 1.60 specific gravity of separation with a clean coal
recovery of 82 percent for the coal from New Mexico. Generally the three coals
of this region also showed a wide range in the levels of trace element content.
The ratios presented in table 13 show that the manganese had the greatest
concentration in the sink 1.60 specific gravity fraction of the coals for the
four regions tested, by factors ranging from 13 to 35. An exception to this
was the cadmium concentration in the sink 1.60 specific gravity fraction of
the Eastern Midwest region coals, which was greater by a factor of 310.
CONCLUSIONS
1. Reliable analytical techniques were developed to determine cadmium,
chromium, copper, fluorine, mercury, manganese, nickel, and lead contents in
the whole coal as well as the various specific gravity fractions of the coal.
The bias of the results produced by the developed techniques ranged from 0 to
17 percent for the various trace elements when comparing the determined values
with those certified by the National Bureau of Standards for SRM 1632. The
precision of the developed techniques was ±15 percent or less when comparing
the cumulative trace element contents of the various specific gravity fractions
of a coal with those obtained from the whole coal.
2. Contamination of samples can occur from lead in automobile exhaust
products, mercury vapor in tanks of laboratory gases, and laboratory equipment
such as beakers and stirring rods.
3. The method of standard additions was found most acceptable for deter-
mining the trace element content of the various specific gravity fractions of
the coals tested.
23
-------
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ro
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r
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1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
5
4
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2
1
3
2
1
n
i i i I
_ COPPER
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y
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i i i i i
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CADMIUM
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S
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1
I I I I
I I I I
i r
i i i i i
50 60 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
6
5
4
3
2
1
n
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_ LEAD ,,
/
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-
1
1.30 1.40 1.60 Total
SPECIFIC GRAVITY
OF SEPARATION
4
3
2
|!
r>
i i i
NICKEL
N
S
S
\
S
\
Sy
\
\
\
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1
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s
\
s
K
i
\
s
s
s
\
\
-
-
1
30
20
10
n
i i
MANGANESE
-------
ro
Ul
3
ttO
40
20
n
a
s
\
s
s
^
1 1 1
FLUORINE '
\
\
\
s
i
\
\
\
s
,'
\
\
\
\
s
1
1
.08
.06
.04
.02
& 15
z I0
UJ
£ 5
8 o
W
Z R
I D
s
u s
Ul
< 3
|E
I '
COPPER
~^-
^\
\|
X|
«M
x
\
\
X
1
xi
X
X
\
\
-------
NJ
UJ
i
60
40
20
n
FLUORINE
^
S
S,
\
\
\
^
1
s
\
\
s
-
\
\
\
^
1
1.30 1.40 1.60 Totol
SPECIFIC GRAVITY
OF SEPARATION
I 5
0.
t-~ 4
H 3
1 «
I '
iu n
i i i i
rt
\
\
\
S
\
\
S
,-"
\
\
\
\
\
\
\
1
R
\
\
\
\
\
\
\
s
"
's
\
\
\
\
\
\
1
_L I
I I
j I
50 60 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
60
40
20
ft
i i i i i
- MANGANESE /
/
\l 1 \| fs^
^1 iv. 1 i is. 1
N
\
\
\
-
-
i
.04
.02
1.30 1.40
Total
SPECIFIC GRAVITY
OF SEPARATION
i i i i i
j I
J-.
50 60 70 80 90 100
CUMULATIVE COAL
RECOVERY, percent
FIGURE 10. - Washability analyses of Rock Springs No. 3 bed coal,
Sweetwater County, Wyo., showing the trace element
content at various specific gravities of separation
and clean coal recoveries.
-------
4. Washability analyses performed on the coals showed that most of the
trace elements presented in this report concentrated in the heavier specific
gravity fractions of the coal, indicating that they are associated with the
inorganic matter. Thus removal of these heavier gravity fractions would re-
sult in significant trace element reductions in the clean coal product.
5. The concentrations of the individual trace elements varied quite a
bit for the various coalbeds within a region and thus for the various regions
also. However, in most instances the concentration ratios for cadmium, chro-
mium, copper, fluorine, mercury, nickel, and lead were 1/10 or less, while
that of manganese was always greater than 1/10 for the coals tested in all
four regions.
27
-------
REFERENCES
1. Abernethy, R. F., M. J. Peterson, and F. H. Gibson. (1969). Spectro-
chemical Analyses of Coal Ash for Trace Elements. BuMines Rept. of Inv.
7281, 30 pp.
2. Abernethy, R. F., and F. H. Gibson. (1967). Method for Determination of
Fluorine in Coal. BuMines Rept. of Inv. 7054, 13 pp.
3. Anderson, J. (1972). Wet Digestion Versus Dry Ashing for the Analysis
of Fish Tissue for Trace Metals. Perkin-Elmer Atomic Absorption News-
letter, vol. 11, No. 4, pp. 88-89.
4. Babu, S. P., ed. (1975). Trace Elements in Fuels. Advances in Chemistry
Series No. 141, American Chemical Society, Washington, D. C., 216 pages.
5. Blake, H. E., Jr. (1963). Fluorine Analyses, Control Methods for Various
Compounds. BuMines Rept. of Inv. 6314, 29 pp.
6. Bolten, N., J. Carter, J. Emery, C. Feldman, W. Fulkerson, T. Hulett, and
W. Lyon. (1973). Trace Element Mass Balance Around a Coal-Fired Steam
Plant. Oak Ridge National Laboratory, Contract W-7405-ENG-26, 80 pp.
7. Capes, E. E., A. E. McElhinney, D. S. Russell, and A. F. Sirianni. (1974).
Rejection of Trace Metals From Coal During Beneficiation by Agglomeration.
Environ. Sci. Technol., v. 8, No. 1, pp. 35-38.
8. Crossley, H. E. (1944). Fluorine in Coal, II. The Determination of
Fluorine in Coal. J. Soc. Chem. Ind., v. 63, pp. 284-288.
9. Diehl, R. C., E. A. Hattman, H. Schultz, and R. J. Haren. (1972). Fate
of Trace Mercury in the Combustion of Coal. BuMines Tech. Prog. Rept. 54,
9 pp.
10. Fieldner, A. C., and W. A. Selvig. (1938). Notes in the Sampling and
Analysis of Coal. BuMines Tech. Paper 586, 48 pp.
11. Forney, A. J., W. P. Haynes, S. J. Gasior, R. M. Kornosky, C. E. Schmidt,
and A. G. Sharkey. (1975). Trace Element and Major Component Balances
Around the Synthane PDU Gasifier. U.S. ERDA/PERC TPR 75/1, 23 pp.
12. Holmes, J. A. (1918). The Sampling of Coal in the Mine. BuMines Tech.
Paper 1, 22 pp.
13. Luke, C. L. (1967). Spectrophotometrie Determination of Traces of
Several Metals and Alloys After Isolation by Iodide Extraction. Anal.
Chim. Acta., v. 39, pp. 447-456.
14. Magee, E. M., H. J. Hall, and G. M. Varga, Jr. (1973). Potential Pollu-
tants in Fossil Fuels. EPA-R2-73-249, 151 pp.
15. McGowan, G. E. (1960). The Determination of Fluorine in Coal, an
Adaptation of Spectrophotometric Methods. Fuel, v. 39, pp. 245-252.
28
-------
16. 0'Gorman, J. V., and P. L. Walter, Jr. (1972). Mineral Matter and Trace
Elements in U. S. Coals. The Pennsylvania State University, College of
Earth and Mineral Sciences, Research and Development Report No. 61,
183 pp.
17. Pollock, E. N. (1975). Trace Impurities in Coal by Wet Chemical Methods.
In Trace Elements in Fuels, ed. by S. P. Babu. Advances in Chemistry
Series 141, American Chemical Society, Washington, D. C., pp. 23-24.
18. Ruch, R. R., H. J. Gluskoter, and N. F. Shimp. (1974). Occurrence and
Distribution of Potentially Volatile Trace Elements in Coal.
EPA-650/2-74-054, 96 pages.
19. Schlesinger, M. D., and H. Schultz. (1972). An Evaluation of Methods for
Determining Mercury in Some U. S. Coals. BuMines Rept. of Inv. 7609,
11 pp.
20. Schultz, H., E. A. Hattman, and W. B. Booher. (1975). The Fate of Some
Trace Elements During Coal Pretreatment and Combustion. In Trace Elements
in Fuels, ed. by S. P. Babu. Advances in Chemistry Series No. 141, Ameri-
can Chemical Society, Washington, D. C., pp. 139-153.
21. von Lehmden, D. J., R. H. Jungers, and R. E. Lee, Jr. (1974). Determina-
tion of Trace Elements in Coal, Fly Ash, Fuel Oil, and GasolineA Pre-
liminary Comparison of Selected Analytical Techniques. Anal. Chem.
v. 46, 7 pp.
22. Zubovie, P., N. B. Sheffey, and T. Stadnichenko. (1967). Distribution of
Minor Elements in Some Coals in the Western and Southwestern Regions of
the Interior Coal Province. U. S. Geol. Survey Bull. 1117-D, 33 pp.
23. Zubovie, P., T. Stadnichenko, and N. B. Sheffey. (1966). Distribution of
Minor Elements in Coals of the Appalachian Region. U. S. Geol. Survey
Bull. 1117-C, 37 pp.
24. Zubovie, P., T. Stadnichenko, and N. B. Sheffey. (1964). Distribution of
Minor Elements in Coal Beds of the Eastern Interior Region. U. S. Geol.
Survey Bull. 1117-B, 41 pp.
25. Zubovie, P., T. Stadnichenko, and N. B. Sheffey. (1961). Geochemistry of
Miner Elements in Coals of the Northern Great Plains Coal Province.
U. S. Geol. Survey Bull. 1117-A, 58 pp.
29
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i. REPORT NO.
EPA-600/7- 7 8-038
2.
3. RECIPIENT'S ACCESSION-NO.
Washability and Analytical Evaluation
of Potential Pollution from Trace Elements in Coal
5. REPORT DATE
March 1978
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
J.A.Cavallaro, G. A. Gibbon, and A.W.Deurbrouck
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Department of Energy
Division of Solid Fuel Mining and Preparation
Washington, DC 20585
1O. PROGRAM ELEMENT NO.
E HE 62 3 A
11. CONTRACT/GRANT NO.
EPA/DoE Inter agency
Agreement DXE685 AJ
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
EPA, Office of Research and Development*
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
14. SPONSORING AGENCY CODE
EPA/600/13
15.SUPPLEMENTARY NOTESCosponsored by j^Ef EPA project officer is David A. Kirchges-
sner (IERL-RTP), Mail Drop 61, 919/541-2851.
16. ABSTRACT
repOrt giv6s results of a. was liability study showing the trace element
contents of various specific gravity fractions for ten coal samples collected from
four coal producing regions of the U.S. Reliable analytical methods were developed
to quantitatively determine cadmium, chromium, copper, fluorine, mercury, man-
ganese, nickel, and lead in whole coals. Generally, the data showed that most of the
trace elements of interest concentrated in the heavier specific gravity fractions of
the coal, indicating that they are associated with mineral matter. Removing this
material should reduce trace elements significantly.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Pollution
Coal
Trace Elements
Chemical Analysis
Analyzing
Washing
Pollution Control
Stationary Sources
Washability
13B
08G
06A
07D
14B
13H,07A
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
38
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
- 30 -
OUS. GOVERNMENT PRINTING OFFICE: 1978 261-324/23 1-3
------- |