&EPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 2771 1
EPA-600/7-80-003
January 1980
Abundance of Trace
and Minor Elements in
Organic and Mineral
Fractions of Coal
Interagency
Energy/Environment
R&D Program Report
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EPA-600/7-80-003
January 1980
Abundance of Trace and Minor Elements
in Organic and Mineral Fractions
of Coal
by
J.K. Kuhn, F.L Fiene, R.A. Cahill,
H.J. Gluskoter, and N.F. Shimp
Illinois State Geological Survey
University of Illinois
Urbana, Illinois 61801
Contract No. 68-02-2130
Program Element No. EHE623A
EPA Project Officer: N. Dean Smith
Industrial Environmental Research Laboratory
Office of Environmental Engineering and Technology
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ABSTRACT
New data on the abundance and mode of occurrence of trace and minor elements in coal are
presented in this report. A summary of related studies previously conducted at the Illinois
State Geological Survey is also included.
Twenty-seven coals, fifteen from Illinois, three from West Virginia, three from Alabama,
two from Montana, and one each from Pennsylvania, Arizona, North Dakota, and Wyoming, were
selected for study in the new phases of this work. Each coal sample underwent acid treatment,
and selected coals underwent float/sink and ion exchange treatments. From these treated samples,
coal fractions were obtained and analyzed by various methods.
An enriched organic-matter fraction, virtually free of mineral matter, was prepared by
extracting coal under prescribed conditions with dilute nitric, hydrofluoric, and hydrochloric
acids. Excluding organic sulfur, the resulting demineralized product contained no detectable
coal minerals and only 250 to 600 ppm of ash-forming elements. These elements, and certain
of the more volatile ones, are securely bound within the organic coal matrix; consequently,
they were termed organically associated.
The concept of an organic affinity index was used to measure the tendency of an element to
associate with the organic matter in coal. Of the elements studied, B, Be, Br, Ge, and Sb were
consistently classified organic; sulfide-forming elements, In, As, Cd, and Fe, were classified
inorganic; and others, such as Al, Ca, Ga, Ni, P, Si, and Ti, were intermediate or variable in
their association. Generally, concentrations of organically associated trace elements were low,
the lowest of which occurred in western coals. Conversely, western coals contained the greatest
number of elements associated with organic matter.
Three general observations were made: (1) the total concentration of an element in coal is
not indicative of its concentration in the organic phase; (2) because concentrations vary widely,
accurate appraisals of trace and minor element associations by the methods used require that
each coal be evaluated separately; and (3) the highest concentrations of trace and minor ele-
ments in coal are associated with mineral matter.
The validity (accuracy) of results for elements associated with the organic phase of coal
was supported by the unexpectedly good agreement between two independent sets of values. One
set was obtained by direct analysis of the acid-treated coal; a second set of values was derived
from extrapolation of adjusted washability curves to zero percent recovery. Initially, these
curves were used for calculating the organic affinity index. The values obtained by extrapola-
tion represent the theoretical concentration of an element in a coal when no mineral matter is
present. Further evidence for valid results stems from the fact that acid treatment did not
alter organic sulfur concentrations and, therefore, probably did not significantly alter the
coal structure itself.
In some coals, variations existed between values obtained from the two independent pro-
cedures for estimating organically associated elements; however, these differences can be
explained by exchangeable ions on coal surfaces and by the solubility of some minerals. Acid
treatment of coal removed exchangeable and soluble ions, but float/sink procedures did not.
Failure to remove these elements from the coal organic fraction inflated the organic affinity
index. Differences were apparent for Na, Ca, Mg, Ba, and B in western low-rank coals where,
for example, more than 70 percent of the total Ca and Mg occurred in soluble or exchangeable
forms. When allowance for such differences is made, the values for organically associated
elements obtained by the two methods are in good agreement; they are thought to be reasonable
estimates of concentrations in coal organic matter.
Despite evidence that many elements exhibit some degree of organic association, most of the
trace and minor elements in these coals were in a mineral form. Thus many elements could be
significantly reduced by physical cleaning procedures. The degree of reduction depends on the
mineral, its size, and its distribution. Detailed mineralogic and microscopic analyses of low-
temperature ash residues were made of gravity separations from nine of the coals. The same
mineral data were obtained for 26 of the 27 whole coals studied. Western coals had distinctly
in
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different mineral suites than Illinois and eastern coals; kaolinite predominated over other clay
minerals, and significant amounts of bassanite were formed during the low temperature ashing
process. Western coals also contained minor quantities of calcite, quartz, and pyrite. Gen-
eral associations were compiled for trace elements with minerals.
This report was submitted in partial fulfillment of Contract No. 68-02-2130 by the Illinois
State Geological Survey and the University of Illinois, under partial sponsorship of the U.S.
Environmental Protection Agency, Industrial Environmental Research Laboratory, Fuel Process
Branch, Research Triangle Park, NC.
ACKNOWLEDGMENTS
This publication is based on data which were obtained with partial support from U.S. EPA
Contract No. 68-02-2130 and U.S. EPA Grant R804403 and R806654.
This financial support is gratefully acknowledged as is the cooperation of the University
of Illinois, which administered the contracts. The coal companies in Illinois and other states
contributed greatly to the success of this project by allowing the collection of samples in their
mines. An expression of gratitude is extended to S. D. Hampton, L. R. Henderson, E. Fruth,
L. R. Camp, M. Siefrid, R. A. Keogh, L. B. Kohlenberger, R. D. Harvey, S. M. Rimmer, J. A.
Schleicher, R. J. Helfinstine, J. Thomas, Jr., and others at the Illinois State Geological Survey
for their efforts on the project. Special thanks are due E. S. Gladney, Los Alamos Scientific
Laboratories, NM, who performed the boron determinations, and to C. W. Kruse for helpful comments
on the manuscript.
iv
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CONTENTS
Abstract iii
Acknowledgments . . ' iv
Figures v
Tables vi
I. Introduction 1
II. Conclusions and recommendations 3
III. Methods 4
Sampling 4
Analytical 4
Chemical demineralization 5
Physical demineralization 8
Exchangeable ions. .-....' 10
Displaying washability data 10
Calculating the organic affinity index 12
Mineralogic methods 17
IV. Results 18
Whole coal and demineralized coal 18
Concentrations of organically associated elements 18
Exchangeable and soluble ions 43
Mineralogy 43
V. Discussion 50
Validity of organically associated elements 50
Variability of organically associated elements 53
Comparative data 54
Importance of mineral matter 58
Coal cleaning application 58
VI. References 64
FIGURES
Number Page
1 Germanium in specific gravity fractions (Davis Coal) 11
2 Gallium in specific gravity fractions (Blue Creek Coal, AL). . 11
3 Washability curve of sulfur in specific gravity fractions (Herrin [No. 6] Coal). ... 12
4 Washability curve for chromium in specific gravity fractions (Herrin [No. 6] Coal) . . 13
5 Adjusted washability curve for chromium in specific gravity fractions (Herrin [No. 6]
Coal) 14
6 Washability curves for lead in specific gravity fractions (Herrin [No. 6] seam). ... 16
7 Washability curves for boron in specific gravity fractions (Pittsburgh [No. 8]
seam, WV) 16
8 Organic affinity index for total sulfur and ratio of organic to total sulfur in 9
washed coals 17
9 Mineral distributions in a single sample (Herrin [No. 6] Coal) 46
10 Comparison of independently determined concentrations of organic sulfur in 9 coals . . 51
11 Comparison of independently determined'concentrations of organically associated
trace elements (Davis Coal) 51
12 Comparison of independently determined concentrations of organically associated
trace elements (Pittsburgh [No. 8] seam, WV) 51
13 Comparison of independently determined-concentrations of organically associated
trace elements (Rosebud Coal, MT) 51
14 Comparison of independently determined concentrations of organically associated
trace elements (Herrin [No. 6] seam) 52
15 Elemental concentrations of calcium in ammonium acetate (ion-exchanged) samples. ... 52
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TABLES
Number Page
1 Whole coal selections 5
2 Analytical methods used in this study 6
3 Effect of physical and chemical treatment on elemental concentrations (Illinois
No. 6 Coal) 7
4 LAH extraction versus HNOj extraction 9
5 Chromium in specific gravity fractions (Herrin [No. 6] Coal) 13
6 Comparison of concentrations of trace and minor elements in raw and demineralized
(MMF) Coal 19-30
7 Mean concentrations in mineral-matter-free and raw coals 31
8 Identification of coal samples and gravity separations 32-33
9 Concentrations and organic affinities of elements (Herrin [No. 6] Coal) 34
10 Concentrations and organic affinities of elements (Davis Coal) 35
11 Concentrations and organic affinities of elements (Herrin [No. 6] Coal) 36
12 Concentrations and organic affinities of elements (Pittsburgh [No. 8] seam, WV) . . . 37
13 Concentrations and organic affinities of elements (Pittsburgh [No. 8] seam, WV) . . . 38
14 Concentrations and organic affinities of elements (Pocahontas [No. 4] seam, WV) . . . 39
15 Concentrations and organic affinities of elements (Blue Creek seam, AL) 40
16 Concentrations and organic affinities of elements (Rosebud seam, MT) 41
17 Concentrations and organic affinities of elements (Black Mesa Field, AZ) 42
18 Comparison of concentrations of minor and trace elements in coal and NH,AC extracted
residue 44
19 Results of qualitative mineral analysis of low-temperature ashes 45
20 Results of mineralogical analysis 47-48
21 Results of clay mineral analysis (<2ym fraction of LTA) of 2 coals 49
22 Prediction of mean elemental concentrations in mineral-matter-free coal for 3 basins. 55
23 Total retention percentages of elements and concentration summations for demineralized
coal and ash or mineral-matter content for whole coal 56
24 Mean MMF values for coal compared to plant material and crustal abundance (ppm) ... 57
25 Elements commonly associated with the principal minerals found in coals 59
26 Organic association of trace elements in coal: Illinois coals 60-62
VI
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SECTION I
INTRODUCTION
Although coal is the most abundant fossil fuel resource in the United
States, environmental restraints are preventing its optimum use. A
primary cause of these restraints is the occurrence of accessory elements
and minerals in association with the coal. Their abundance and especially
their type of association or combination can have a significant effect on
the ease with which these elements and minerals are removed before the
coal is used. For example, organic sulfur, which is not removed from coal
by physical cleaning methods, appears in process streams and effluents as
an undesirable constituent and must be removed later. Adverse characteris-
tics may be identified in other organically associated elements in coal.
An element's form does affect the extent to which it can be removed or
recovered.
Little direct evidence for the kinds and concentrations of elements
in the organic fractions of coal is available. That some elements in coal
have either a high organic or inorganic affinity was considered more than
40 years ago by V. M. Goldschmidt, who pioneered modern investigations of
trace elements in coals. He identified trace elements in inorganic
(mineral) combination in coals. He also postulated the occurrence of metal-
organic complexes in coal; the observed concentrations of vanadium, molyb-
denum, and nickel were attributed to the presence of such complexes
(Goldschmidt, 1935).
Nicholls (1968) plotted the concentration of an element in coal or in
coal ash against the ash content of the coal. Diagrams depicting a number
.of such points for a single coal seam, or for a group of coal seams in a
single geographic area, were interpreted for degree of inorganic or organic
affinity of the element. Nicholls described elements as (1) associated
with the organic fraction, (2) generally associated with the inorganic
fraction; and (3) elements that could be associated with either or both
fractions.
Horton and Aubrey (1950) handpicked pure vitrain samples from coals
and separated the samples into five different specific gravity fractions.
They then analyzed these fractions for minor elements. For the three
,vitrains that were studied, they concluded that beryllium, germanium, vana-
dium, titanium, and boron were contributed almost entirely by the inherent
(organically combined) mineral matter and that manganese, phosphorus, and
tin were associated with the adventitious (inorganically combined) mineral
matter.
Results of investigations of the organic-inorganic affinities of trace
elements in coals were published by Zubovic, Stadnichenko, and Sheffey (1960,
1961, 1964). In more recent articles Zubovic (1966, 1976) listed 15 elements
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in decreasing order of percentage of organic affinity. He suggested also
(1976, p. 50) that the metals having high organic affinities in coal are
present as chelates.
Ruch, Gluskoter, and Shimp (1974) and Gluskoter (1975) published
tables of organic affinities for 21 elements determined on four samples
of Illinois coals, which had been separated into specific gravity fractions
in the laboratory. They listed the elements in decreasing order of organic
affinity, but numerical values were not given for the index. Since these
results were published, Gluskoter et al. (1977) and Kuhn et^al. (1978)
reported washability data for up to 53 elements and 10 coal parameters
from seven additional coals. They calculated an index of organic affinity
from washability curves for the elements determined in the washed coals.
Gluskoter et al. (1977) presented tables that listed the organic affinity
index values for nine coals and ranked the elements as "organic,"
"intermediate-organic," "intermediate inorganic," and "inorganic." Each
coal analyzed was ranked separately because an element that is "organic"
in a sub-bituminous coal from Wyoming may be "inorganic" in an Appalachian
coal. A study recently completed at the Illinois State Geological .Survey
and briefly reported by Kuhn et al. (1978) used chemical demineralization
of coal as a totally independent approach. The study obtained results
that were applied to the determination of organic affinities. Fiene,
Kuhn, and Gluskoter (1978) reported on the mineral phases found in the
same coal samples as those studied by Gluskoter et al. (1977), Kuhn et al.
(1978), and Kuhn, Fiene, and Harvey (1978). The study determined minerals
in both the low temperature ashes of the coals and their specific gravity
fractions. Data from these studies are summarized in this report and are
combined with results of our new research to provide a single source of
information on the occurrence of organically associated trace elements in
coal.
The scope of this work includes nine coals, separated into specific
gravity fractions, from the eastern, central, and western portions of the
United States. To gain a wider distribution of sample types, another 18
coals were also subjected to chemical demineralization. Ion exchange
determinations were performed on seven coals. Chemical and mineralogical
analyses were made on all of these materials; however, in an effort to
remain as concise as possible, only the values regarded as pertinent to
conclusions for this study are presented.
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SECTION II
CONCLUSIONS AND RECOMMENDATIONS
The chemical form of an element influences its behavior during coal
processing and pyrolysis. In this study, procedures for determining the
forms in which minor and trace elements occur in coal were investigated.
Two methods—chemical and physical—were used to prepare highly
enriched organic fractions of coal. Comparison of results from analyses
of these fractions enabled reasonable estimates to be made of the concen-
trations of up to 45 minor and trace elements associated with coal organic
matter. These values, all of which were low in comparison to total amounts,
are believed to represent the theoretical lower limit attainable for an
element in cleaned coal. The concept of an organic affinity index to
measure the tendency of an element to remain with the coal organic matrix
is reviewed and expanded.
Forms of elements other than organically associated ones were also
investigated; significant concentrations of exchangeable and acid soluble
.elements, e.g., Ca and Mg, are more abundant in western coals than in
eastern or Illinois Basin coals. Unless these elements were first removed
or taken into account, estimates of the organically associated elements
were inflated for the low rank coals. In addition, the western coals con-
tained different mineral suites. General mineral associations were
compiled for trace and minor elements.
Chemical form is believed to be only one of the factors controlling
element behavior. Preliminary evidence from our current research indicates
that the occurrence and distribution of certain elements in the products
of pyrolysis is also influenced by the conditions under which coal is
pyrolyzed. Thus, an element with a high organic affinity—or two different
elements with equally high affinities—may report to very different coal
fractions when pyrolyzed under different conditions. A knowledge of
process conditions and organic affinities needs to be considered if accurate
estimates are to be made of distributions of elements in process streams.
Organic affinity indexes, if made sufficiently accurate for a range
of coals, could be used in conjunction with total concentrations for deter-
mining, in addition to sulfur, the chemical forms of many elements, for
estimating the theoretical percentage of an element that can be removed
by coal cleaning, and for predicting material balances in the coal products
and wastes. Before this is feasible, however, additional evidence for the
validity of the organic affinity concept is needed.
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SECTION III
METHODS
SAMPLING
Twenty-five of the 27 coals used in this study were face-channel or com-
posite face-channel samples collected in coal mines by Illinois State Geolo-
gical Survey personnel. The two exceptions were obtained from a Federal
agency. The 25 samples were hand cut and represent the full face of the coal
seam excluding mineral bands, nodules, and partings greater than 1 cm thick,
following an established procedure described by Holmes (1911). All were air
dried and riffled according to standard procedures of the American Society
for Testing and Materials (1978a). Representative portions of the raw coal
were stage ground to -60 mesh (250 ym) for chemical analysis and low-
temperature ashing and to -100 mesh (149 ym) in a Pitchford uniform-particle-
size grinder for trace element determinations. Subsamples used for acid
demineralization were comminuted to less than -325 (44 ym) mesh in a ball
mill. Table 1 lists the whole coal samples used in these projects; each
material is assigned an analysis number ("C" number), which is used for
identification throughout this report.
ANALYTICAL .
Analytical methods used for the analysis of samples are given in table 2.
Details of these methods were reported by Gluskoter et al. (1977), except for
the energy dispersive X-ray fluorescence method, which is contained in Ruch
et al. (1979). Although the methods are the same, the elements determined by
each method are not entirely comparable with those described by Gluskoter
et al. Methods requiring ashing procedures, e.g., atomic absorption and
optical emission, could not be used because of the extremely low level of ash
in the acid demineralized coal (MMF). Except in the case of Be, attempts to
analyze whole coal samples by optical emission failed because the necessary
sensitivity could not be achieved.
In most cases, for any particular element, a single method was used to
analyze an entire set of samples. However, for the nine float/sink sets,
different methods were used for some elements and could bias results, espe-
cially at very low concentrations.
This study uses three different approaches to the investigation of the
mode of occurrence of trace elements in coals. The first approach is based
on differences in specific gravity or "coal washing" and seldom, if ever,
results in a complete separation of mineral matter from the coal. Rather,
a fractionation results in which the parts are enriched in either mineral or
organic matter. A second approach, which is basically a chemical demineral-
ization of the coal, was used in an attempt to achieve a more complete sepa-
ration of the. organic and mineral fractions of coal than is possible by
gravity separations. Extraction of exchangeable ions with a neutral, buffered
solution was the third approach used.
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TABLE 1. Whole coal selections
Number
C-18126t
C- 16543
C-16993
C-17001 *
C- 18304
C- 18560*
C- 18704
C-18816
C- 18820*
C-18841*t
C-18848*t
C- 18857
C-.19000*t
C-18571
C- 18844
C-19824*t
C-19854*t
C- 18824
C-18440t
C- 18748
C-18320
C-18368
C-18445
C- 18457
C- 14684
C- 15999
C-16173*
Coal seam
Herrin (No. 6)
Herrin (No. 6)
Herrin (No. 6)
Davis
De Koven
Herrin (No. 6)
Herrin (No. 6)
Mammoth
Pocahontas (No. 4)
Pittsburgh (No. 8)
Blue Creek
Herrin (No. 6)
Black Mesa Field
Herrin (No. 6)
Pittsburgh (No. 8)
Pittsburgh (No. 8)
Rosebud
Johnson
Noonan
Abbott Fm.
Herrin (No. 6)
Herrin (No. 6)
Rosebud
Hanna 24
Herrin (No. 6)
Herrin (No. 6)
Herrin (No. 6)
State
Illinois
Illinois
Illinois
Illinois
Illinois
Illinois
Illinois
Montana
West Virginia
West Virginia
Alabama
Illinois
Arizona
Illinois
Pennsylvania
West Virginia
Montana
Alabama
North Dakota
Illinois
Illinois
Illinois
Montana
Wyoming
Illinois
Illinois
Illinois
*Samples for which gravity separations were made.
•[•Samples for which ion exchange determinations were made.
CHEMICAL DEMORALIZATION
The method used to chemically remove minerals from the organic fraction
of the coal is a variation of the procedure for the determination of forms of
sulfur in coal (American Society for Testing and Materials, 1978b), in which
HC1 and HN03 are used under prescribed conditions to extract sulfate and
pyritic sulfur. In this study, HF is also used to dissolve the silicate
minerals in a manner similar to that described by Bishop and Ward (1958) and
by the International Organization for Standardization (1974).
The coal was first floated at 1.40 specific gravity in perchloroethylene
and naphtha to reduce the mineral phases, especially pyrite. Dissolution of
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TABLE 2. Analytical methods used in this study
Instrumental neutron activation:
Fe, Na, K, Mn, Sc, Cr, Co, Ni, Zn, Ga, As, Se, Ba, Rb, Sr, Mo, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb,
Dy, Yb, Lu, Hf, Ta, W, Th, U, I,* Ag,* Au*
X-ray fluorescence—Wavelength dispersive:
Si, Al, Fe, Ca, Mg, Ti, P, Mn, V, Cu, Pb
Direct reading optical emission:
Be
Prompt gamma ray/neutron activation:''"
B
X-ray fluorescence—Energy dispersive:
Ba, Cd, I,* In,* Sn,* Te*
*Elements not reported. Most values were below detection limits.
"t"Work performed by E. S. Gladney, Los Alamos Scientific Laboratories, NM.
the minerals in the demineralizing solutions could add to the concentration
of elements associated with the organic matter, and it was deemed desirable
to reduce elemental concentrations in the solutions as much as possible. We
have assumed, as others have in the past, that the coal organic material is
unaltered by this process, although little evidence is available to support
or disprove the assumption.
The float fraction was then comminuted to less than -325 (44 ym) mesh,
and 10-gram samples were placed in a flask containing a cold finger condenser
and. 50 ml of 10 percent HN03 and refluxed for 1, 2, or 3 hours. The materi-
als were quantitatively removed from the flask and were filtered, washed, and
dried at room temperature overnight. The samples were then placed in poly-
ethylene flasks, covered, and allowed to digest in 49 percent HF at 70°C for
periods of 1, 2, or 3 hours. The material was again quantitatively removed
from the flasks, filtered in plastic funnels, washed, and dried. Finally
the materials were placed in a flask and, utilizing a cold finger condenser,
were refluxed for 1 hour with 25 percent HC1 at approximately 100°C. After
refluxing, the materials were quantitatively removed from the flasks, fil-
tered, washed, and dried. (Yields of coal organic material from this pro-
cedure were not measured.) The samples were subsequently analyzed by the
analytical methods in table 2.
A number of coals were processed by this procedure to ascertain the
conditions for use with subsequent samples. An example of the results is
shown in table 3. It was concluded from these tests that no significant
advantage was gained from refluxing the materials for 3 hours. Because the
intent was to cause as little change in the nature of the coal as possible,
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TABLE 3. Effect of physical and chemical treatments
on the concentrations of some elements
in a Herrin (No. 6) Coal sample
Raw coal
Element
Al
Si
Ca
K
Na
Cl
S
Fe
Ti
Organic S
P
As
Pb
Br
Cu
Ni
Zn
V
Rb
Cs
Ba
Sr
Sc
Cr
Co
Ga
Se
Sb
Hf
W
La
Ce
Sn
Eu
Dy
Lu
Yb
Tb
Th
U
Mo
Hg
Mn
00
1.40
3.20
.51
.13
.04
.05
6.45
2.60
.06
2.55
(ppm)
50
3.4
<.l
3.5
13
24
43
36
23
2.0
54
28
4.1
21
5.5
2.4
4.3
.4
1.1
.5
6.1
25
.8
.2
1.2
<.02
.8
.4
3.6
1.9
18
.23
60
1.40 float
(%) (ppm)
1.08
2.15
.094
.11
.027
3.59
.90
.08
2.66
13
2.8
<.l
3.4
13
7.5
20.5
28
10
.7
42
10.3
2.8
16.8
3.7
2.8
1.4
.2
.5
.3
3.4
7.3
.8
.2
.6
.5
.1
1.9
.5
3.5
.1
10.3
1-hr 2-hr 3-hr
treatment * treatment * treatment *
(%) (ppm) (*)
124
250
33
1
7
2.64 2.52
170
25
2.64 2.52
9.7
.1
<.l
2.4
3.4
2.5
8.8
6.1
<1
<.l
21
1.8
.9
8.8
.4
.9
.2
.1
.1
.1
.9
1.8
.4
.1
.5
.2
.1
.9
.2
.5
.4
(ppm) 00
35
41
25
1
5
2.54
66
11
<1 .0
.1
<.l
2.9
2.1
<-|
4.4
3.5
<1
<.01
3.6
1.3
.5
6.2
.4
.6
.3
.1
.1
.6
1.5
.35
.1
.4
.02
.20
.09
.88
.09
.44
.3
(ppm)
31
42,
23
1
6
65
14
<1.0
!l
< .1
2.5
2.2
1
4.0
3.3
<1
<.01
2.8
1.1
.5
6.1
.4
.6
.2
.1
.1
.6
1.5
.3
.1
.5
.2
.1
.9
.1
.4
.2
NOTE: All values normalized to raw coal.
includes HN03 and HF but not HC1.
-------
the 2-hour refluxing and digestion procedure was adopted. This procedure
was selected although it is recognized that in some instances, such as, in
peat or materials with high silicon content, total elimination of the
mineral-matter content in coal may not result.
Further tests were made to determine the extent to which the coals were
demineralized. The acid-extracted coal product was subjected to low tempera-
ture ashing, a process which destroys organic matter but leaves minerals
relatively unaltered. Ash percentages ranged from 0.32 percent to 1.69
percent, and x-ray diffraction analysis of the residues failed to detect any
of the minerals originally present in the whole coals. Only traces of chlo-
ride and fluoride were detected, and these probably originated in the acid
treatment. The absence of detectable minerals from the whole coal supported
the belief that the samples were now virtually free of mineral matter.
It is known that HN03 oxidizes organic materials; consequently, a
second procedure was investigated using the reducing agent lithium aluminum
hydride (LAH), instead of HN03, for removal of pyrite and other sulfides.
Previous work has shown the procedure to be an acceptable and, in some
instances, a preferable substitute for the HN03 digestion (Lawlor, Fester,
and Robinson, 1963; Kuhn, Kohlenberger, and Shimp, 1973). Table 4 compares
the results of the two procedures, and although a few minor differences
exist (e.g., Fe and Mn), the two sets of values compare quite favorably.
While the procedure using LAH yields approximately the same values as the
nitric acid method, the latter was selected because it requires less time
and is less hazardous.
Another aspect which was considered during development of the deminer-
alization procedure is the common occurrence of minute, widely disseminated
mineral grains, which may be occluded within organic coal particles. For
this reason, the coals extracted for this study were pulverized to a very
fine size (approximately -325 mesh) after the 1.40 gravity separation was
performed. Because some mineral particles occur as submicron crystallites,
the data determined may well represent the limits to which the coal can be
cleaned by practical methods. The terms "organic association" and "organic
affinity" rather than "organic combination" are, therefore, preferred for
elemental concentrations in "mineral-matter-free" coal.
PHYSICAL DEMORALIZATION
About half of the coals produced in the United States are "washed" or
"cleaned" prior to delivery to the consumer. Cleaning involves reducing the
content of ash and sulfur of the coal by removing a portion of the mineral
matter associated with the coal. Because specific gravities of the minerals
in coal are from two to four times greater than that of the organics (macer-
als) in the coal, conventional coal-cleaning techniques involve specific
gravity separations.
Nine coal samples were separated into specific gravity fractions and
were analyzed for major, minor, and trace elements. Gravity separations
were made on a 3/8-inch by 28-mesh fraction, obtained by stage grinding
and screening the coal. The sized coal was separated into five or six speci-
fic gravity fractions ranging from 1.28 float to 1.60 sink in mixtures of per-
chloroethylene and naphtha. Chlorine values in the washed coals are unreli-
able because relatively large and variable amounts of this element may have
-------
TABLE 4. LAN extraction versus HN03 extraction
IL No. 6
C- 14684
Element
Al
Si
Ca
K
Na
Fe
Ti
P
V
Cu
Rb
Cs
Ba
Sr
Br
Sc
Cr
Mn
Co
Ni
Zn
Ga
As
Se
Sb
Hf
W
La
Ce
Sm
Eu
Dy
Lu
Yb
Tb
Th
U
Mo
LAH
(ppm)
45
.65
10
<10
<4
700
58
2
4
2.2
<1.0
.1
<10
2.9
15
.1
3.3
1.3
.5
<10
<1
.5
3.7
.6
.2
<.l
<.5
1.5
1.6
.2
.2
<.l
<.l
<.l
.3
<.l
<1
HN03
(ppm)
82
98
19
<10
1
93
58
5
6
2.2
<1.0
4.2
3.5
9.2
.6
4.6
.3
.9
3.6
<1
.5
.2
.3
.5
.2
.1
.8
.4
.2
.2
<.l
.2
.6
.1
.4
Subbituminous
C-18457
LAH
(ppm)
115
83
21
<10
21
800
43
<1
2.0
2.1
<.l
<10
6.2
1.0
.2
4.1
6.0
.1
<1
<1
.3
.7
.4
.2
<.l
<.l
.6
1.2
.1
.2
<.l
<.l
<.l
.2
<.3
<.5
HN03
(ppm)
78
69
16
<10
11
56
30
<1
2.1
2.4
1.2
.06
2.6
3.7
.1
.4
1.2
.2
.2
<5
<1
.4
.5
.3
.2
.3
.1
1.0
1.2
.1
.2
.1
.7
.1
.4
IL No. 6
C-15999
LAH
(ppm)
282
122
74
<2
4
900
60
7
4
1.6
<1
<.l
<10
8.1
7
1.3
<1
5.0
1.0
<5
<1
1.5
4.0
1.0
.8
<.l
<.5
2.0
1.1
.5
.1
.6
<.l
<.2
.4
1.2
.2
1.3
HN03
(ppm)
77
81
41
<1.1
6
64
56
5
7
1.4
<1
<.l
4.6
5.5
6
1
7.4
.3
.4
4.7
<1
.8
<.l
.3
.5
.1
.1
.6
1.3
.22
.1
.5
<.l
.2
<.l
.6
.3
.6
IL No. 6
C-18560
LAH
(ppm)
400
95
80
<5
18
700
100
6
5
2
<1
<.l
<10
7.9
4.8
2.2
8.4
4.6
2.4
<1
<1
1.3
1.3
1.2
<.l
<.l
<.5
1.3
1.5
.7
.1
.9
<.l
.4
.8
3.7
<.l
.6
HN03
(ppm)
35
41
25
1
6
66
90
<1
3.5
2.1
<1
.1
.2
1.5
3.3
.6
6.8
.3
.4
<1
<1
.7
.1
.3
.1
.1
<.5
.7
1.7
.4
.1
.5
.2
.1
1.0
.1
.5
-------
been absorbed by the coals from the washing media. Therefore, these deter-
minations have been deleted from the results.
EXCHANGEABLE IONS
Weakly bound (exchangeable) elements and soluble minerals were extracted
from seven whole coals with ammonium acetate. Some minerals such as calcite,
if present, were dissolved and extracted with the exchangeable ions; no
attempt was made to distinguish between the two. For convenience, ions'extracted
by this process are termed exchangeable.
Coals used for the exchangeable ion studies were reduced to -325 mesh,
and 10 grams were placed in a 300 ml polyethylene flask. Fifty mL of ammon-
ium acetate (IN) were added to the flask, and the mixture, at an approximate
temperature of 70°C, was then stirred for 20 hours. At the end of the
exchange/dissolution period, the material was vacuum filtered while being
flushed with sufficient ammonium acetate solution to bring the volume up to
450 mL. A final flush with 50 mL of ethyl alcohol was performed, and the
sample was then vacuum dried. Elemental determinations were made on the
residual coal material.
METHOD OF DISPLAYING WASHABILITY DATA
The float-sink or washability data can be displayed as washability
curves and histograms. Data on the washability characteristics (sulfur and
ash reduction) of many Illinois coals have been presented by Helfinstine
et al. (1970) and by Helfinstine et al. (1971, 1974). Cavallaro et al.
(1978) published washability curves for eight elements in ten coal samples
collected from various coal-producing regions of the United States. The
elements they determined were Cd, Cr, Cu, F, Hg, Mn, Ni, and Pb.
Figures 1 through 3 are examples of washability curves and histograms
for three elements. The figures are presented in order of increasing
tendencies of the elements to be concentrated in the heavier fractions
(decreasing organic affinity). The washability curve is a type of cumulative
curve from which the expected concentration of an element in a coal can be
read at any given recovery rate, if one assumes that the separation was based
on specific gravity differences. Therefore, the abscissa is "recovery of
float coal in percent" and should be applicable to any specific gravity
separation without regard to the medium in which it is done or the method
used. The raw coal concentration of an element is read at the 100-percent
recovery point; the concentration in the cleanest coals (most free of mineral
matter) is read at the low recovery end of the curve (generally in the range
20 to 30 percent recovery).
Figure 1 shows the washability curve and the histogram for germanium in
a sample from the Davis Coal Member. The negative slope of the curve indi-
cates that germanium is concentrated in the clean coal fractions; this is
also apparent from the histogram.
An element that is uniformly distributed in the various fractions of the
washed coal will have a flat washability curve with a slope of zero. Washing
such a coal will have no effect on the concentration of the element in the
clean coal.
10
-------
a
E
c
(0
E 3.8'
1.9
20 40 60 80
Percentage of recovery
Davis Coal
100
10.0
8.5
7.1-
5.7-
4.3-
2.9-
1.4-
0.0-
m*m
u^m
n
1.28 1.29 1.31 1.40 1.60 2.89 >2.9
Specific gravity fraction
Davis Coal
ISGS 1980
Figure 1. Germanium in specific gravity fractions of a sample from the Davis Coal Member. Left: Washability
curve. Right: Distribution of germanium in individual fractions.
A positive slope of the washability curve shows that the element is
concentrated in the inorganic (mineral matter) portion of the coal. The more
strongly associated the element is with the inorganic fraction, the steeper
is the slope of the curve. Washability data on Ga in a sample from the Blue
Creek coal seam in Alabama give a washability curve having a positive slope.
The curve does not approach the origin (fig. 2); rather, when extended, the
curve intercepts the ordinate at approximately 3.5 ppm.
6.5
5.2-
E 3.9-
a
1.3-
0.0.
20 40 60
Percentage of recovery
80
100
a
27-
24-
21-
18-
15-
12-
9-
~
3-
(4)
(5)
(6)
(8)
(22)
1.30 1.32 1.40 1.60
Specific gravity fraction
>1.60
ISGS 1980
Figure 2. Gallium in specific gravity fractions of a sample from the Blue Creek coal from Alabama. Left: Washability curve.
Right: Distribution of gallium in individual fractions.
11
-------
Sulfur is present in coals in both
organic and inorganic combinations;
standard analyses report the varieties
of sulfur as sulfate sulfur, pyritic
sulfur, and organic sulfur. In a sample
from the Herrin (No. 6) Coal in Illinois,
the was liability curve for total sulfur
shows the contribution from,both organic
and inorganic sulfur (fig. 3). The
sulfur content decreases rather rapidly
in the washed coal as that part that is
concentrated in the heavier mineral-
matter-rich portion (inorganic sulfur)
is removed. Then the curve flattens
because the lighter coal fractions also
contain appreciable amounts of sulfur
(organic sulfur).
3 2.9-
1.9-
1.0-
0.0
20
40
60 SO
Percentage of recovery
100
ISGS 1980
Figure 3. Washability curve of sulfur in
specific gravity fractions of a
sample from the Herrin (No. 6)
Coal Member.
METHOD OF CALCULATING THE ORGANIC AFFINITY INDEX OF AN ELEMENT
Washability curves and histograms of washability data are effective
means of depicting the mode of combination of elements in coal—they indicate
whether the elements are associated with the organic or inorganic fractions
of the coal. However, a much easier means of comparing results for different
elements or coals was needed. Therefore, an attempt has been made to quan-
tify the information presented on the curves by producing an "organic
affinity" index. .
The present report expands upon the work of Gluskoter et al. (1977) and
clarifies both the rationale and the techniques used to obtain a value for
an index of organic affinity. This is both appropriate and necessary because
certain values obtained during the derivation of the index are germane to the
verification of the elemental concentrations determined in demineralized coal.
The decision to name the index "organic affinity" rather than "inorganic
affinity" was arbitrary; one is the inverse of the other.
The shape of the washability curve is dependent upon the mode of occur-
rence of the element, the analyses of which are plotted on the curve. There-
fore, the area under the curve is also dependent upon the mode of occurrence
of the element. The value for the organic affinity index for a specific
element is obtained by calculating the area beneath the washability curve.
This calculation is done on a curve that has been drawn to a predetermined
and constant scale (normalized) and on a curve that has been adjusted for
that part of the mineral matter that is inseparable from the lightest coal
fraction. An example of the calculations necessary to obtain the organic
affinity index follows using the data for chromium in table 5. A normal
washability curve can be constructed with cumulative concentration values
generated from the following equation:
- [CALPPM(I-l)
-
SUMPCT(I-I)] + [RECPCT(I)
SUMPCT(I)
ANLPPM(I)]
where,
12
-------
TABLE 5. Chromium in specific gravity fractions of a washed sample of Herrin
(No. 6) Coal in Illinois (normal and adjusted cumulative concentrations)
Percentage Cumulative Cumulative Cumulative
Specific of raw Chromium Low percentage of chromium Adjusted adjusted
Analyses gravity coal (ppm) temperature raw coal (ppm) chromium chromium (ppm)
number fraction (RECPCT) (ANLPPM) ash (%) (SUMPCT) (CALPPM) (ppm) (CALPPM)
C18123
C18124
C18125
C18126
C18127
C18128
1.25F
1.29FS
1.33FS
1.40FS
1.60FS
1.60S
36.1
17.4
14.7
9.3
6.9
15.6
8.0
12
16
25
33
71
3.84
88.4
36.1
53.5 .
68.2
77.5
84.4
100
8.0
9.3
10.7
12.5
14.1
23.0
4.9
8.9
12.9
21.9
29.9
67.9
4.9
6.2
7.7
9.4
11.1
19.9
CALPPM = the cumulative elemental concentration,
SUMPCT = the cumulative coal recovery percentage,
RECPCT = the coal recovery percentage in the fraction being calculated,and
ANLPPM = the analytical concentration of the element-in the fraction
being calculated.
This curve (fig. 4) graphs the cumulative concentrations (column 7) versus
the cumulative percentage of recovery (column 6) in table 5. For ease of
handling the data and for making additional calculations, the washability curve
is plotted in a square format in which the lengths of the abscissa and ordinate
at 100 percent recovery are equal.
In this case, the washability curve (fig. 4) suggests chromium is princi-
pally in the inorganic form; but even the cleanest fraction tested has 8 ppm
chromium, and if the curve were extrapolated to the vertical axis, it would
intersect well above the origin. The separation of mineral matter from or-
ganic matter in specific gravity fractions of coal is not absolute; mineral
matter is present in the cleanest (lightest) gravity fraction that could pos-
sibly be obtained. Some of the chromium may be present as part of this insep-
arable mineral matter; therefore, ad-
justment of the curve for this possi-
ble contribution must be made before
calculating the area under the curve.
The amount of inseparable
mineral matter is assumed to be
equal to the percentage of low
temperature ash in the lightest
gravity fraction. The low tem-
perature ash is determined by
radio-frequency ashing at a tem-
perature below 150°C. The other
necessary assumption is,,that the con-
centration of chromium in the mineral
matter (LTA) of the 1.25 float frac-
tion (lightest fraction in this case)
23.0
20
ISGS 1980
40 60
Percentage of recovery
Herrin (No. 6) Coal
80
100
Figure 4. Washability curve for chromium in specific gravity
fractions of a sample of the Herrin (No. 6) Coal.
13
-------
is the same as the concentration of
chromium in the mineral matter of
the 1.60 sink fraction. This
assumption is certainly not as
accurate as one would wish because
it tends to overestimate the amount
of an element contributed by insep-
arable mineral matter, and there-
fore, conclusions concerning the
amount of organically associated
elements (in this case, chromium)
are conservative.
An adjusted cumulative curve is
constructed after a value (F) for
chromium in the inseparable mineral
matter is subtracted from each of
the concentrations that were
determined on the various speci-
fic gravity fractions by using
the.foil owing example of calcu-
lations for F:
19.9
15.9-
a
11.9-
E
o
o
80
100
Percentage of recovery
Herrin (No. 6) Coal
ISGS 1980
Figure 5. Adjusted washability curve for chromium in specific
gravity fractions of a sample of Herrin (No. 6) Coal.
F (inseparable Cr) = 71 ppm x 3.84 = 3.1
88.4
ppm
3.84 is the percentage of low temperature ash in the lightest (1.25
float) fraction.
88.4 is the percentage of low temperature ash in the heaviest (1.60 sink)
fraction.
71 ppm is the chromium content of the 1.60 sink fraction.
CALPPM(I) = [(CALPPM(I-I) • SUMPCT (1-1)] + [(RECPCT(I) • (ANLPPM(I)- F)]
SUMPCT (I)
Table 5 lists the normal and adjusted data and the calculated cumulative
values from which an adjusted washability curve can be constructed (fig. 5).
The washability curves shown in figures 4 and 5 are very similar. The
adjusted curve for Cr (fig. 5) has been "lowered" and the extrapolated inter-
cept of the vertical (zero mineral matter) axis has a lower value. (A con-
stant value for the inseparable mineral matter (3.1 ppm) was subtracted from
the concentration in each fraction. However, a more accurate correction may
be obtained by subtracting variable amounts based on the percentage of low
temperature ash in each gravity fraction.) The total area of the square on
which the adjusted washability curve is drawn is defined to have the value
of 1.00'at 100 percent recovery. The percentage of that area that lies
beneath the curve, expressed as a number with two figures to the right of the
decimal is the index of organic affinity. (The significance of a second
decimal place has not been determined.) The area under the curve can be'
determined by constructing a polynomial curve to fit the datum points and
14
-------
deriving the value mathematically; or, more simply, a line can be drawn
through the points and the area planimetered by hand or by computer methods
(digitizer). The digitizer method produced the most reliable results and
was used exclusively in this study.
An element that is removed, to any degree, from the clean coal fraction
by washing the coal has a value of less than 1.00; for example, see Pb in
figure 6. The organic affinity of lead in that sample is 0.08, an extremely
low value, indicating that the element is present almost entirely in the
mineral-matter fraction.
An element may have an organic affinity greater than 1.00, as in the
case for boron in a sample of the Pittsburgh (No. 8) seam from West Virginia
(fig. 7). Both standard and adjusted washability curves for B are shown in
figure 7. The lighter specific gravity fractions of the coal contain larger
amounts of B than the heavier fractions that are rich in mineral matter.
Boron is an element that often has a high organic affinity index—in this
case, 1.14. Standard and adjusted curves are nearly identical, inasmuch as
there is only a minor contribution from the inseparable mineral matter to
the total boron content. The organic affinity index is an open-ended scale.
The upper limit is dependent only upon the difference between the concentra-
tion of the element in the clean coal at the extrapolated Y intercept and the
concentration of the element in the coal prior to washing (adjusted end point).
A number of metals have washability curves intermediate between those
elements that are generally concentrated in the inorganic fraction (such as
zinc) and those that are concentrated in the organic fraction (such as
bromine).
Chromium in the Herrin (No. 6) Coal (table 5, figs. 4 and 5) is an
example. The adjusted curve intersects the ordinate at a lower value than
does the standard curve. But even with the removal of a hypothetical amount
of chromium contained in the inseparable mineral matter, there is still
an appreciable amount of chromium left in the cleanest, organic-rich coal
fractions. The calculated organic affinity of chromium in this sample is 0.37.
Precision and Accuracy of Organic Affinity
There are many potential sources of errors in the analyses and calcu-
lations leading to an index of organic affinity. The washability data
(percentage of total coal in each specific gravity fraction), the chemical
analyses for the element or other constituent, and the amount of low tem-
perature ash in the various fractions are all used in making the calculation;
any error in their determinations affects the organic affinity values.
One set of values exists with which the results can be tested. Varie-
ties of sulfur (pyritic sulfur, organic sulfur, and sulfate sulfur) as well
as total sulfur had been determined on fractions of washed coal samples.
The percentage of sulfate sulfur is very low and generally does not make a
significant contribution to the total sulfur content of a fresh coal sample.
If analyses for varieties of sulfur were precise and accurate, if measure-
ments of the amount of coal in each washability fraction were accurate, and
if measurements of the amount of low-temperature ash were accurate, a perfect
correlation should result between organic affinity of total sulfur and per-
centage of organic sulfur in the total sulfur.
This relationship is shown for the nine coals in figure 8. The agree-
ment is generally good and well within analytical error for determining those
15
-------
101.4
69.5
55.6-
-41.7-
27.8-
13.9-
20 40 60 80
Percentage of recovery
Herrin (No. 6) seam, northwestern Illinois
0.0
100
-I 1 1 •-! 1—• 1-
20 40 60
Percentage of recovery (adjusted)
Herrin (No. 6) seam, northwestern Illinois
100
ISGS 1980
Figure 6. Washability curves for lead in specific gravity fractions of a sample from the Herrin (No. 6) seam. Left: Standard wash-
ability curve. Right: Adjusted washability curve.
90
72-
54-
36-
18-
20
40
60
90
72-
E 54
a
a
o
co 36
18-
80 100
Percentage of recovery (adjusted)
Pittsburgh (No. 8) seam, West Virginia
20 40 60 80
Percentage of recovery
Pittsburgh (No. 8) seam, West Virginia
100
ISGS 1980
Figure 7. Washability curves for boron in specific gravity fractions of a sample from the Pittsburgh (No. 8) seam from West Virginia.
Left: Standard washability curve. Right: Adjusted washability curve.
16
-------
factors mentioned above for eight of the nine coals analyzed. One point
representing a sub-bituminous coal from Montana is anomalous. It arises
from the unusual washability characteristics of this coal with regard to
total sulfur. Virtually all of the pyritic sulfur in the raw coal sample
was removed in the 1.60 sink fraction and there was no detectable pyritic
sulfur present in the lighter fractions. Therefore', the assumption, made
during the calculation of the organic affinity, that the concentration of
sulfur in the inseparable mineral matter of the heaviest and lightest frac-
tions were the same, was invalid. In this case the organic affinity calcu-
lated on the unadjusted washability curve is more nearly correct. The know-
ledge that such anomalies exist contributes to better interpretation of such
data and the organic affinity index.
MINERALOGIC METHODS
Qualitative mineralogic analyses of 26 of the 27 raw coals and detailed
mineralogic studies of single samples of nine raw coals (see table 1) and
their various specific gravity fractions were conducted in conjunction with
chemical analyses. The samples were characterized by x-ray diffraction
analyses and microscopic examination of low-temperature-ash (LTA) residues
prepared from the coal. The original minerals contained in the coal were
retained by this radio-frequency plasma ashing technique. Because tempera-.
tures are sufficiently low (<150°C), the mineral phases are not significantly
altered by oxidation, dehydration, or decomposition (Gluskoter, 1965). Semi-
quantitative mineralogic analyses of the major nonclay minerals using an
internal standard and prepared calibration curves were carried out by methods
adapted from Ward (1977) and Russell and Rimmer (1979). Mineral phases in
the LTA in quantities of <1 percent were generally not detectable above
background intensities. The total clay percentage was obtained by sub-
traction. Clay mineral, analysis of the <2 ym fraction was conducted using
the preparation and analytical methods of Stepusin (1978).
1.20
1.00-
>
.«
.5 .80
3:
ro
u
-Z .40-
.20-
AZ
• WV
WV
IL
IL
Organic sulfur x 100
Total sulfur
MT
10
20
30
40
50
60
70
80
90 100
ISGS 19BO
Figure 8. Organic affinity index for total sulfur and the ratio of organic to total sulfur in nine washed coal samples.
17
-------
SECTION IV
RESULTS
WHOLE COAL AND DEMORALIZED COAL
Twenty-seven samples of coal, collected from three geographical areas of
the United States, were prepared, demineralized, and analyzed as previously
described. Of these samples, six were from the eastern region, six from the
western region and fifteen from the Illinois Basin. Whole coal, 1.40 float
material, nitric acid digested material, and the demineralized product from
the 1.40 gravity separation were all analyzed for major and minor ash-forming
elements and for trace elements. Of the analytical results, those for whole
coal and "mineral-matter-free" coal are most significant to this study. These
are presented in table 6. The whole coal values were calculated to the
moisture-free basis. The organic portion of the 1.40 gravity separation is
assumed to be equivalent to the organic portion of the whole coal, i.e., only
the mineral matter content is affected by the separation. Percentage reten-
tion of the elements was calculated, and it is also presented in table 6.
When the concentration of the element retained was below the detection limit,
no percentage was calculated. If the detection limit is approached for both
the whole coal and the mineral-matter-free product, the resulting retention
percentage may be subject to considerable error, e.g., ± 100 percent.
Table 7 presents the mean elemental concentrations for the whole coals
and the demineralized material from the different geographical regions repre-
sented. For the purpose of simplicity the coals were divided into three
regions; however, an inspection of the standard deviation of the values will
indicate that for some elements the variation between samples from the same
region is greater than the variation between regions. The implications of
this fact will be discussed later.
CONCENTRATIONS OF ORGANICALLY ASSOCIATED ELEMENTS
Table 8 identifies the coals and lists the specific gravity fractions
that were obtained from the nine coals used in this portion of the project.
Data from these float-sink sets have been used to calculate the relative
organic affinities and the elemental concentrations for the whole coals
when the adjusted washability curves are extrapolated to 0 percent recovery
(tables 9-17). The analytical data for the individual gravity fractions in
table 8 are not given because data are so extensive and have been reported
in Gluskoter et al. (1977), p. 90-104, except for set 4 from sample 18841 and
set 8 from sample C19854. The results for these two sets are given in Kuhn
et al. (1978), p. 5-8.
(text continues on page 43)
18
-------
TABLE 6. Comparison of concentrations of trace and minor elements in raw and demineralized (MMF) coal
Sample
no.
C- 181 26
C-16543
C-16993
C-17001
C- 18304
C-18560
C-18704
C-18816
C-18820
C- 18841
C- 18848
C-18857
C- 19000
C-18571
C- 18844
C- 19824
C-19854
C- 18824
C- 18440
C- 18748
C-18320
C- 18368
C- 18445
C- 18457
C-14684
C-15999
C-16173
Raw
coal
(X)
2.48
2.06
3.47
2.08
3.31
3.20
2.50
1.92
2.51
2.34
2.80
2.80
0.71
1.50
1.90
1.95
2.41
3.00
1.30
1.00
3.20
2.90
1.33
.71
2.12
3.01
1.92
Si
MMF*
(ppm)
36
39
69
197
53
41
57
51
56
64
64
48
53
44
76
40
30
63
88
60
60
44
45
69
98
81
52
Retention f
(X)
0.1
.2
0.2.
1.0
.2
0.1
0.2
.3
0.2
.3
0.2
..2
0.7
.3
0.4
0.2
0.1
.2
.7
.6
» .2
.1
.3
1.0
.5
.3
.3
Raw
coal
(«)
1.12
1.51
1.05
0.86
1.72
1.40
1.70
1.54
1.41
1.23
1.90
1.10
1.40
0.85
1.20
1.02
1.15
2.00
.89
.43
1.60
1.40
.99
.36
1.18
1.57
.92
Al
MMF*
(ppm)
60
65
73
125
199
41
41
41
169
282
236
67
187
65
82
41
20
57
71
65
48
44
58
78
82
77
65
Retentiont
(*)
0.5
0.4
0.7
1.4
1.2
.3
0.2
.3
1.2
2
1.2
0.6
1.3
0.8
0.7
0.4
0.2
.3
.8
.02
1.5
.3
.6
2.2
.7
.5
.7
Raw
.Coal
(*)
1.83
1.59
2.96
2.76
2.79
2.60
0.63
0.60
0.56
1.73
0.70
2.20
0.40
3.80
1.30
1.12
.47
.61
.33
.57
1.81
2.10
.38
.21
.69
1.78
1.60
Fe
MMF*
(ppm)
55
93
58
64
100
66
143
60
72
242
54
67
225
113
146
80
35
46
22
12
55
50
30
56
120
75
67
Ca
Retentiont
(*)
0.3
0.6
0.2
0.2
0.4
0.3
2.3
1.0
1.3
1.4
0.8
0.3
5.6
0.3
1.1
0.7
0.8
.8
.7
.2
.3
.2
.8
2.7
1.7
.4
.4
Raw
coal
- («)
.73
2.67
0.63
0.82
0.17
0.51
1.00
0.83
0.56
0.53
0.35
0.48
0.46
2.70
0.55
1.61
0.97
.15
1.70
.22
.88
.62
2.10
3.89
.54
.21
.56
MMF*
(ppm)
13
28
51
67
200
25
14
44
74
213
48
27
199
85
38
30
20
21
31
31
46
41
58
16
19
41
.64
Retentiont
(%)
.2
.1
.8
.8
12
.5
.1
.5
1.3
4
1.4
.6
4.3
.3
.7
.2
.2
1.4
.2
1.4
.5
.7
.3
<.l
.3
.8
1.1
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal,
-------
t-o
o
Sample
no.
C-18126
C-16543
C-16993
C-T7001
C-18304
C-18560
C- 18704
C-18816
C-18820
C-18841
C- 18848
C-18857
C-19000
C-18571
C-18844
C-19824
C-19854
C-18824
C- 18440
C-18748
C-18320
C- 18368
C-18445
C- 18457
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
200
405
280
700
200
400
1820
170
700
730
338
950
1650
125
260
676
191
180
3550
. 230
700
244
no
90
640
236
351
Na
MMF*
(ppm)
6.6
6.6
8
25
20
6
15
<3
0.5
6
<3
4
1.4
<3
6
8.8
15
30
4
3.5
.8
4
<2
11
1.0
6.0
<2
Retentiont
w
3.3
1.6
2.9
3.6
,10.0
1.5
0.8
.1
0.8
0.4
.1
2.3
1.3
7.8
16.7
.1
1.5
.1
1.6
1.2
.2
2.5
Raw
coal
(*)
0.05
0.04
0.07
0.02
0.04-
0.06
0.16
0.10
0.06
0.04
0.05
0.05
0,07
0.05
0.04
0.16
0.44
.03
.28
.04
.07
.05
.19
.12
.04
.05
.05
TABLE
Mg
MMF*
(ppm)
43
33
40
95
29
21
37
14
18
7
<20
<20
<20
20
<20
<20
<20
49
<20
<20
<20
17
23
15
21
18
15
6 . Continued
Retention t
8.6
8.2
5.7
47.5
7.2
3.5
2.3
1.4
3.0
1.7
16
3.4
1.2
1.3
5.2
3.6
3.0
Raw
coal
0.17
0.14
0.20
0.14
0.13
0.13
0.21
0.02
0.23
0.25
0.29
0.17
0.02
0.07
0.14
0.09
0.09
0.12
0.03
0.37
0.19
0.20
0.01
0.02
0.13
0.23
0.11
K
MMF*
(ppm)
1.3
1.3
40
31
<2
-------
TABLE 6: Continued
Sample
no.
C- 181 26
C- 16543
C- 16993
C- 17001
C- 18304
C-18560
C- 18704
C- 1881 6
C- 18820
C- 18841
C- 18848
C- 18857
C- 19000
C-18571
C- 18844
C- 19824
C- 19854
C- 18824
C- 18440
C-18748
C-18320
C- 18368
C- 18445
C- 18457
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
21
24
84
48
192
50
76
76
26
59
190
31
120
62
68
103
121
62
150
158
52
25
90
16
75
10
110
P
MMF*
(ppm)
1.4
0.1
2.5
2.8
2
<1
11
3
0.1
2
<4
7
<4
4
5
<5
<5
4
<2
11
8
1
2
<1
5
3
2
Retention t
(%)
6.7
0.4
3.0
5.8
1.0
14.4
4.0
.4
3.4
22.6
- 6.4
7.3
6.4
7.0
15.4
4.0
2.2
6.7
30.0
1.8
Raw
coal
(ppm)
76
93
75
18
20
62
146
32
14
20
13
54
8
260
10
35
85
29
52
120
37
13
112
42
34
15
191
Mn
MMF*
(ppm)
0.3
0.8
0.5
0.7
0.8
0.3
0.4
2.1
0.5
3.7
<1
0.4
0.4
0.3
0.3
0.68
1.5
6.7
6.1
5.1
4
.3
.5
.2
.3
.32
.74
Retention t
w
.4
.9
.7
3.9
4
.5
.3
6.5
3.6
18
0.7
4.8
0.1
3.0
1.9
1.7
23.1
11.7
4.2
10.8
2.3
.4
.5
.9
2.1
.4
Raw
coal
(%}
3.25
3.15
4.15
4.14
3.59
6.45
2.63
1.00
0.79
5.01
0.55
5.02
0.61
6.10
2.30
2.23
0.90
.98
.51
.92
3.56
3.93
.83
.54
1.40
3.31
3.52
S
MMF*
(%)
.12
.93
.76
.57
.07
1.81
2.00
0.45
0.47
2.28
0.33
2.30
0.32
1.71
1.15
1.18
0.46
.56
.43
.36
1.98
1.93
.61
.27
.65
1.36
2.03
Organic S
Retention t
(*)
34.5
61.3
42.4
37.9
29.8
28.1
76.0
45.0
59.5
45.5
60.0
45.8
52.5
28.0
50.0
52.9
51.1
57.1
84.3
39.1
55.6
49.1
73.5
50.0
46.4
41.1
57.7
Raw
coal
(%)
1.15
1.91
1.65
1.51
.99
1.87
2.08
.45
.50
2.35
.36
2.25
.38
1.80
1.20
1.15
.58
.54
.47
.38
1.87
2.07
.59
.25
.72
1.38
2.14
MMF*
(%)
1.12
1.93
1.76
1.57
1.07
1.81
2.00
.45
.47
2.28
.33
2.30
.32
1.71
1.15
1.18
.45
.56
.43
.36
1.98
1.93
.61
.27
.65
1.36
2.03
Retentiont
(*)
97
101
107
104
108
97
96
100
94
97
92
102
84
95
96
103
97
83
91
95
106
93
103
108
90
99
95
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal.
-------
KJ
TABLE 6. Continued
Sampl e
no.
C-18126
C-16543
C- 16993
C-17001
C- 18304
C-18560
C-18704
C-18816
C-18820
C-18841
C- 18848
C-188&7
C- 19000
C-18571
C- 18844
C- 19824
C- 19854
C- 18824
C-18440
C-18748
C-18320
C- 18368
C- 18445
C-18457
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
2.8
2.4
1.3
1.6
2.2
1.4
0.7
0.49
0.88
0.66
0.68
1
0.39
2.9
0.58
0.45
0.47
1.0
.55
2.6
1.1
1.0
.20
.31
.80
1.5
.96
Be
MMF*
(ppm)
0.03
0.04
0.02
0.06
0.11
0.03
0.03
0.11
0.01
0.05
0.05
0.03
0.13
0.05
0.07
0.03
.08
.01
.14
.02
.03
.08
.009
.02
.03
.05
Raw
Retention t coal
(%) (ppm)
1
2
1
4
5
2
4
12
1
8
5
8
4
9
2
6
8
2
5
2
3
40
3
2
2
5
100
81
81
37
68
200
264
66
12
120
15
37
110
48
82
100
40
44
18
230
210
91
16
33
82
241
B
MMF*
(ppm)
6.6
7.7
6.6
6.1
11
6.6
10
5.5
9.7
24
5.1
8.8
5.3
8.5
16
13
18
12
8.3
8.3
5.7
2.2
4.9
7.7
13
Retention t
(%)
6.6
9.5
8.1
1.6
16.2
3.3
3.8
8.3
80.8
20.0
34.0
14.3
7.7
33.3
32.5
40.9
66.7
36.1
39.5
6.2
13.8
14.8
9.4
5.4
Raw
coal
(ppm)
3.5
3.1
2.6
2.9
3.0
4.1
2.7
1.8
5.5
4.8
8.0
3.2
1.6
1.5
1.8
2.3
1.6
7
1.2
4.7
3.5
3.7
1.4
.8
1.9
3.0
1.7
Sc
Raw
MMF* Retentiont coal
(ppm) (%) (ppm)
.13
.11
.2
.9
.04
.65
.5
.2
2.0
1.3
2.5
.5
.42
.25
.62
.08
.6
1.2
.09
1.6
.7
.5
.1
.36
.55
1.0
.37
4
3
8
31
1
16
18
11
36
27
31
16
26
17
34
3
37
17
7
34
20
13
7
45
29
33
22
32
32
54
62
34
34
83
31
62
32
77
32
8
18
42
17
11
60
31
173
34
32
20
2.6
33
36
23
V
MMF*
(ppm)
8.5
9.2
2
1.6
3
3.5
17
1
1.5
4
<5
<5
<5
<5
6.5
2.7
1.2
32
5.2
1.5
1.1
4
2.1
2.1
6
7
7
Retention **
(*)
26
28
4
2
9
10
20
3
2
12
15
16
11
53
17
1
3
12
10
80
18
19
30
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
•(•Concentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal
-------
TABLE 6. Continued
Sample
no.
C- 181 26
C-16543
C- 16993
C- 17001
C- 18304
C-18560
C-18704
C- 1881 6
C- 18820
C- 18841
C- 18848
C-18857
C- 19000
C-18571
C- 18844
C- 19824
C- 19854
C- 18824
C- 18440
C- 18748
C-18320
C-18368
C-18445
C-18457
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
32
14
17
15
19
20
42
13
20
17
26 .
33
3.4
36
15
14
6.2
31
8.4
22
50
47
9.2
6
14
23
14
Cr
MMF*
(ppm)
5.2
5.4
.5
<5
5.0
7
•7
1.2
6.3
8.6
14
7
1.4
3.7
6.1
2.0
0.6
6.7
.8
8
12
6
1.8
1.2
4.6
7.4
6
Retention
16
38
3
26
34
17
9
31
50
54
21
41
10
41
14
10
22
9
36
24
13
20
20-
33
32
43
Raw
t coal
(ppm)
7.7
13
3.9
2.0
4.0
7.2
3.5
2.5
7.5
2.9
18
4
1.1
6.5
1.7
2.2
2.0
8.6
1.0
5.9
3.7
4.0
.8
.6
3.0
5.2
1.9
Co
MMF*
(ppm)
0.2
0.4
0.2
<1
0.6
0.4
0.3
0.6
5.4
0.8
10
0.3
0.5
0.6
0.8
0.2
1.5
3.7
.1
.9
.4
.5
.2
.15
.9
.35
• .3
Raw
Retentiont coal
(%) (ppm)
3
3
5
15
6
9
24
72
28
55
7
45
9
47
10
75
43
12
15
11
12
25
25
30
7
17
32
23
12
17
14'
24
37
8.5
12
14
15
14
2.6
18
6.4
13
3
13
4
20
20
19
2.6
4.4
12
15
22
Ni
Raw
MMF* Retentiont coal
(ppm) (%) (ppm)
<3
5
<5
<4
1
-------
TABLE 6. Continued
N)
Sampl e
no.
C-18126
C-16543
C-16993
C-17001
C-18304
C-18560
C-18704
C-18816
C-18820
C- 18841
C- 18848
C-18857
C-19000
C-18571
C- 18844
C- 19824
C-19854
C- 18824
C- 18440
C- 18748
C-18320
C- 18368
C- 18445
C- 18457-
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
2668
5700
41
27
27
57
31
13
12
14
2
50
3
17
16
10
4
120
<4
26
60
75
6
24
13
75
1200
Zn
MMF*
(ppm)
3
<1
4
<1
<1
1
<1
<1
<1
<1
<1.0
<1
<0.5
<5
<5
-------
TABLE 6. Continued
NJ
ui
Sample
no.
C-18126
C- 16543
C- 16993
C-17001
C- 18304
C-18560
C- 18704
C-18816
C- 18820
C-18841
C- 18848
C- 18857
C- 19000
C- 18571
C- 18844
C- 19824
C- 19854
C- 18824
C- 18440
C- 18748
C-18320
C-18368
C-18445
C-18457
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
16
8
17.5
23
16
3.4
6.6
0.5
24
10
2.5
5
0.9
2.6
18
12
1.6
1.7
1.0
39
13
1.8
1.5
1.2
23
8.5
1.8
Br
MMF*
(ppm)
6.3
3.6
16
24
7.4
3.3
4.2
0.6
16
3.8
1.7
4
1
1.7
20
12
4.5
4.8
3.5
24
3.0
1.1
.82
.1
9.2
6.0
1.2
Retentiont
39
45
91
100
46
97
64
100
67
38
68
80
65
100
61
23
60
55
8
40
71
67
Rb
Raw
coal MMF*
(ppm) (ppm)
14 <1
8.7 <1
14.5
25 <1
20 <1
23 <1
32 <1
1.5 <1
16 <1
13 <1
18 <1
22 <1
1.2 <1
8.3 <1
10 <1
9.5 <1
3.3 <1
17
1.32 <1
47 3
14 <1
23 <1
<1
1.9 <1
15 <1
17 <1
10 <1
Raw
Retentiont coal
(*) (ppm)
19
23
27
17
95
33
37
244
126
105
122
30
204
55
140
200
95
35
240
6 80
40
33
108
218
40
23
16
Sr
Mo
Raw
MMF* Retentiont coal MMF*
(ppm) (%) . (ppm) (ppm)
<1.0
2
10
8
15
1.5
3.0
50
13
3
24
4.4
<5
<5
<3
3.7
3.5
5.5
<1
9
37
47
10
4
8
40
11
10
12
5
2
9
24
9.1 <1
5.8 <1
<1.0 <1
2.4
11 0.5
1.5 <1
<1
4.6 <1.0
1.1
6.2
6.1 <1.0
<1 .0
16 1.8
<1.0
<2 <0.2
7.1 1.4
12 <5
<1
6.3 <.5
6.8 .6
3.3
.8 <.5
1.4 <.5
7.8 .6
2.6
Retentiont
w
5
11
20
9
8
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal,
-------
TABLE 6. Continued
NJ
Cd
Raw Raw
Sample coal MMF* Retentiont coal
no. (ppm) (ppm) (%) (ppm)
C-18126 28 .1 .4
C-16543 65 1.1 2
C-16993 <.4 <.4
C-17001 2.5 1.2 48
C-18304 <.4 <.4
C-18560 <.l <.l
C-18704 <.3 <.3
C-18816 .2 <.l
C-18820 <.l <.l
C-18841 <.l <.l
C-18848 <.l <.l
C-18857 .2 <.l
C-19000 <.l <.l
C-18571 <.l <.l
C-18844 <.l <.l
C-19824 .24 <.l
C-19854 .22 <.07
C-18824 <.2 <.2
C-18440 <.l <.l
C- 18748 <.2 <.2
C-18320 .3 <.l
C-18368 .3 <.l
C-18445 <.l <.l
C-18457 <.l <.l
C-14684 <.2 <.2
C-15999 1.8 .3 16
C-16173 .4 <.2
4.2
2.2
.36
4.7
.35
.5
.65
3.5
4.6
.25
1.5
.42
.4
.20
.51
6
1.0
2.6
.9
1.2
.54
.5
.61
.4
1.2
1.1
1.0
Sb
MMF*
(ppm)
.6
1.2
<.03
.6
<.03
.1
.2
.4
.6
.1
.7
.1
.2
<.08
.1
.8
.7
.1
.6
.2
.3
.1
.3
.1
.3
.4
.5
Raw
Retentiont coal
(X) (ppm)
15
54
13
18
29
11
13
48
50
29
14
73
38
66
17
56
24
56
35
62
35
47
1
1
1
1
2
2
2
1
2
1
1
2
2
1
.0
.0
.9
.6
.0
.0
.3
.3
.0
.0
.3
.6
.11
.77
.9
.76
.43
.2
.06
.6
.93
.6
.06
.16
.96
.2
.4
Cs
Raw
MMF* Retentiont coal
(ppm) (%) (ppm)
<.01
]03
<.04
<.l
.1
.1
<.l
<.02
.2
.03
.05
<.l
<.05
<.01
<.01
.03
<.04
<.02
.01
.2
.01
.05
<.01
<.05
.01
<.l
.02
3
10
5
10
3
2
4
17
8
1
2
1
5
80
750
48
86
41
54
1500
460
180
72
230
60
265
90
87
130
808
180
500
96
46
92
495
460
40
23
63
Ba
MMF*
(ppm)
2
<2
2
3
3
<2
1
6
33
10
20
<5
15
4
13
27
40
16
8
<2
2
5
5
2
4
4
1
.2
.6
.0
.3
.5
.1
.8
.9
.6
.2
.6
.8
Retentiont
(X)
3
6
3
8
.1
1
18
14
9
6
4
15
21
5
9
2
6
6
1
.6
10
20
3
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal,
-------
TABLE 6. Continued
Sample
no.
C-18126
C-16543
C-16993
C-17001
C- 18304
C- 18560
C-18704
C- 1881 6
C- 18820
C-18841
C- 18848
C- 18857
C- 19000
C-18571
C- 18844
C- 19824
C- 19854
C-18824
C- 18440
C-18748
C-18320
C-18368
C-18445
C-18457
C-14684
C-15999
C-16173
Raw
coal
(ppm)
5
6:1
9.3
6.5
5.6
6.1
9.4
8.5
20
8.7
18
5.7
6.0
5.0
7.2
5.7
5.2
18
5.7
26
5.8
7.1
4.2
4.3
7.5
12
2.9
La
MMF*
(ppm)
.5
.5
.4
.9
2.0
.7
.5
2.5
5.0
2.4
2.8
.5
1.3
.8
1.7
2.6
1.3
2.0
.4
2.0
1.0
1.1
1.3
1.0
.8
.6
.7
Raw
Retentiont coal
(%) (ppm)
10
8
5
14
36
12
5
29
25
28
16
9
22
16
24
46
25
11
7
8
17
15
31
23
11
5
25
5.0
8.6
11.4
16
14
25
20
13
31
15
30
8
6
12
11
16
10
25
8.5
42
25
27
12
8.6
11
18
5.6
Ce
MMF*
(ppm)
.7
.7
1.1
1.9
4
1.7
.9
2.7
4.5
3.3
3.5
1
1.2
1.1
3.1
2.5
3.3
2.5
.6
3
1.7
1.7
1.3
1.2
.4
1.1
1.2
Raw
Retentiont coal
(%) (ppm)
15
8
10
12
29
7
4
21
14
22
12
12
20
9
28
16
32
10
7
7
7
6
11
14
4
6
21
.86
.73
.93
1.3
1.4
.86
1.7
.9
2.6
1.5
2.8
.9
.8
1.4
2.8
.9
.9
2.7
.5
3.3
1.4
1.5
.6
.45
.84
1.6
.38
Sm
Raw
MMF* Retentiont coal
(ppm) (%) (ppm)
.17
.16
.23
.3
.5
.41
.2
.4
.9
.6
.06
.22
.3
.45
.40
.47
.25
.8
.09
.4
.35
.5
.1
.12
.19
.22
.19
20
22
25
23
36
48
12
44
35
40
2
24
37
32
14
50
29
30
18
12
25
33
17
27
23
14
50
.2
.2
.31
.21
'.35
.3
.3
.21
.5
.26
.53
.20
.15
.38
.26
.22
.15
.6
.30
.0
.30
.34
.11
.1
.17
.38
.07
Eu
MMF*
(ppm)
.03
.03
.04
.06
.05
.1
.05
.05
.2
.12
.1
.05
.05
.08
.15
.06
.04
.09
.08
.09
.08
.10
.02
.04
.04
.06
.02
Retentiont
(*)
15
15
13
28
14
28
17
23
40
54
21
25
33
21
58
27
27
15
27
10
27
29
18
40
23
16
29
Concentration in the demineralized residue of the T.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal,
-------
TABLE 6.- 'Continued
NJ
oo
Sample
no.
C- 181 26
C-16543
C-16993
C-17001
C- 18304
C-18560
C- 18704
C-18816
C-18820
C- 18841
C- 18848
C-18857
C- 19000
C-18571
C- 18844
C- 19824
C- 19854
C- 18824
C- 18440
C- 18748
C-18320
C-18368
C- 18445
C- 18457
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
.21
.18
.2
.45
.2
.17
.26
.14
.22
.22
.08
.45
.10
.13
.13
.35
.18
.62
.41
.18
.18
.21
.2
Tb
MMF* Retentiont
(ppm) (%)
.07 33
.07 39
.1
<.08
.05
<1
<.l
<.l
108 36
<.05
.08 17
<.10
.04 31
.05 38
<.2
<.l
.12 19
<.l
<.05
<.l
<.06
Raw
coal
(ppm)
1.1
1.3
.8
1.3
1.4
.8
.93
2
1.6
2.4
.6
.65
1.3
.8
.8
.6
2.4
.5
.95
.72
.38
.51
.82
1.9
.27
O
Dy
MMF*
(ppm)
.2
.4
.4
.4
.2
.9
.7
.2
.4
.2
.33
.18
.25
.4
.10
Retentiont
15
50
31
28
45
29
33
48
38
35
35
30
21
37
Raw
coal
.7
.59
.53
. .5
.9
.84
.45
.61
.75
.5
.80
.27
.24
.67
.29
.30
.32
.83
.55
.87
.84
.77
.37
.26
.39
.72
.26
Yb
Raw
MMF* Retentiont coal
(ppm) (X) (ppm)
.07
.08
.07
.2
.2.
.23
.10
.13
.20
.20
.25
.10
.11
.13
.2
.13
.19
.4
.09
.20
.22
.18
.06
.06
.15
.21
.07
10
13
13
40
22
27
22
21
26
40
31
37
46
19
68
43
59
48
16
23
26
23
16
23
38
29
27
.1
.08
.07
.09
.19
<.02
.08
.09
.18
<.l
.10
.10
.08
.07
.04
.08
.06
.25
<.3
.34
.12
.15
<.02
.06
.05
.11
.08
Lu
MMF*
(ppm)
.02
.02
.01
<.01
.03
<.01
!02
.03
.05
.05
.07
.02
.03
.03
.02
.03
.10
.05
.04
.03
.01
.01
<.02
.04
.03 '
Retentiont
(X)
20
25
14
16
25
33
27
70
20
37
43
25
50
40
15
33
20
17
36
12
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal.
-------
TABLE 6. Continued
VO
Sample
no.
C-18126
C-16543
C- 16993
C-17001
C- 18304
C-18560
C- 18704
C-18816
C- 18820
C- 18841
C- 18848
C- 18857
C-19000
C-18571
C- 18844
C-19824
C-19854
C-18824
C- 18440
C-18748
C-18320
C-18368
C- 18445
C-18457
C- 14684
C-15999
C-16173
Raw
coal
(ppm)
.62
.5
.43
1.0
1.3
1.1
.64
.9
1.5
1.0
1.8
.70
.64 .
.35
'1.0
1.0
1.2
1.7
.9
1.4
1.0
.8
1.1
1.2
.5
.5
1.2
Hf
MMF*
(ppm)
.02
.03
.2
.11
.09
.16
.2
.12
.33
.10
.20
.06
.33
.6
.2
.16
.40
.32
.12
.08
.30
.33
.15
.14
.11
Retentiont
3
6
15
10
14
18
13
12
18
14
31
17
33
60
17
9
44
23
12
10
27
27
30
26
9
Raw
coal
(ppm)
.11
.17
.2
.06
.20
.25
.15
.16
.70
.77
.12
.14
.10
.10
.15
.17
.13
.3
.20
.28
.26
.25
.16
.05
.14
.2
.03
Ta
Raw
MMF* Retentiont coal
(ppm) (%) (ppm)
.04 36
<.02
<.04
<.01
.03 15
.03 20
.09 13
.05 35
.08 47
.07 54
.09 30
.11 55
.12 43
<.05
<.05
.5
.41
1.6
.9
.8
.6
.6
.7
.5
.4
.3
.4
1.2
1.4
.6
.3
.7
1.3
1.1
3.0
.5
.5
.8
.3
.3
.4
.9
W
Pb
Raw
MMF* Retentiont coal MMF* Retentiont
(ppm) (%) (ppm) (ppm) (%)
.06
<.05
.6
.5
.08
.06
<.2
.04
.12
.06
<.l
<.l
<.3
<.05
.15
<.09
<.06
.7
.4
1.3
<.l
<.l
<.07
.06
<.l
<.l
12
37
55
10
10
6
24
15
25
53
36
43
20
72 <1
37
22
<1 <1
11
4.0
1.6
3
12
<1 <1
<0.7 <0.7
68
3.9
25 <1
4.6 <1
7.6 <1
5.5 <1
20 <1
4.0 <1
5.4
2.4
<1
11
24
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal.
-------
TABLE 6. Continued
Samp! e
no.
C-18126
C- 16543
C-16993
C-17001
C- 18304
C-18560
C- 18704
C-18816
C- 18820
C-18841
C- 18848
C-18857
C- 19000
C-18571
C- 18844
C-19824
C- 19854
C- 18824
C- 18440
C- 18748
C- 18320
C- 18368
C-18445
C- 18457
C- 14684
C- 15999
C-16173
Raw
coal
(ppm)
2.4
2.2
2.0
2.8
1.8
3.6
2
3
6.2
2.9
5.4
1.4
1.4
1.37
. 2.40
2.1
2.5
5.4
2.7
3.9
1.4
3.1
2.9
.67
1.8
2.8
1.0
Th
MMF*
(ppm)
.5
.5
.4
.8
.2
1.0
.4
1.0
1.1
.6
.5
.4
.6
.2
.9
1.1
.7
1.5
.6
1.1
.5
.8
1.1
.6
.6
.3
Retention"'"
(X)
20
25
20
29
11
28
20
33
18
21
29
43
18
37
52
31
28
22
28
36
26
38
32
20
35
Raw
coal
(ppm)
3.9
1.7
.8
2.1
1.3
1.9
7.5
1.0
1.0
.73
.9
.84
<.70
4.9
.4
<.6
1.5
2.9
1.0
1.2
1.4
1.5
1.1
•6
.4
1.0
2.0
U
MMF*
(ppm)
.12
<.l
<.l
1.6
.2
.09
.5
.02
.2
.07
.3
<.5
.05
.3
<.l
<.l
.2
.5
.3
.2
.2
<.5
.1
.1
.26
.25
Retentiont
(%)
3
76
15
5
7
2
20
9
33
7
13
17
30
14
13
23
29
26
12
COa internal
surface area
(n>2/g)
209
-254
87
97
58
173
218
277
327
53
98
227
240
241
56
68
236
112
147
35
200
203
232
219
163
155
215
1.40
Float (% recovery)
78
79
70
83
85
79
74
75
80
82
83
92
85
89
87
79
51
57
79
80
78
76
87
Concentration in the demineralized residue of the 1.40 float fraction of the coal.
tConcentration in the mineral-matter-free (MMF) coal divided by the concentration in the raw coal,
-------
TABLE 7. Mean concentrations and mean retention percentages in mineral-matter-free coals*
IL Herrin (No.
Element
Si
Al
Fe
Ca
Na
Mg
K
Ti
P
Mn
S
Organic
Be
B
Sc
V
Cr
Co
Ni
Cu
Zn
Ga
As
Se
Br
Rb
Sr
Mo
Cd
Sb
Cs
Ba
La
Ce
Sm
Eu
Tb
Dy
Yb
Lu
Hf
Ta
W
Pb
Th
U
ISAt
2
1
1
0
0
0
0
S
Raw
Coal
.60±.6%
.28±.3%
.96 ±.9%
.96 ±.8%
592 ±472
.06 ±.03%
.16 ±.05%
.07±0.02%
52 ±30
88 ±75
3.9±1.4%
1.7±.5%
1.5±.8
148 ±81
29±.8
37±17
28±13
5.3±3
21±8
20±9
832±1700
3.2±1
6.8+8
2.6±.9
8.9±7
MMF
56±19
61+14
96i53
38i22
5.8±4
26HO
9. 3H4
30+14
4.1+3
0.72H
1.7±.5%
1.7+!5%
0.041.03
8.1i2
0.41.3
6.5+4
5.713
0.41.2
6.0±5
5.0+3
<5
0.601.1
<1
0.341.2
6.014
6)
Retention . Raw
Percentage Coal
'0.2
0.5
0.5
0.4
1
4
0.6
4
8
0.8
44
98
3
5
1
18
20
8
28
25
—
19
—
13
67
16.817 <1 -
31±11
6.8±4
—
1.1 ±1
1.31.7
237±445
6.8±2
4.1i3
0.9010.6
—
0.41.3
0.041.03
3.3H.5
0.71.2
14.718 1.11.4
0
0
0
0
0
0
0
1. 1±.4
.30±. 1
.26±.l
1.0±.4
.58±.2
.09±.02
.70±.3
.17±.07
.68±.4
29±27
2.1±0.8
2.312
197
0.301.01
0.06+.03
—
0.261.1
0.131.06
0.031.01
0.091.04
—
—
—
0.521.2
0.22+.1
13
13
—
30
3
1
3
36
0.301.1
2
—
26
22
33
13
—
—
—
25
10
2.411.4%
1.94±.6%
l.Oi.5%
0.62+.5%
48H248
0.06+.05%
0.191.09%
O.lOi.04%
85157
20HO
2.0+1.7%
1.0+.74%
0.70+.2
53+42
4.9+2
48i22
20t7
6.816
12i3
22i8
29+45
4.7i2
10+8
3.1i2
1119
14+4
12H53
61 5
—
2.3i2
1.41.6
146161
13i6
21i8
2.21.8
0.41.2
0.021.09
1.710.7
0.581.2
0.131.08
1.31.4
0.371.3
0.571.4
8.9+9
4.1i2
1.2il
Eastern
Retention
MMF Percentage
60+12
1441100
107175
71i72
lOill
25+22
1.8+1
76+68
2.3i2
2.4i3
1.01.7%
It. 7%
0.051.03
14+7
1.2i0.9
9.3113
7.3+4
3.5i4
2.8i2
3.8i2
<1
1.2+0.6
<1
0.581.2
6.7i6
—
29119
—
—
0.401.3
0.081.08
20i9
2.811.2
3.21.7
0.541.3
0.12+.05
—
—
0.191.04
0.06+.03
0.291.2
0.09+.01
0.261.3
—
1.01.4
0. 271.2
0.2
0.7
1
1
2
4
0.1
8
3
12
50
100
7
26
24
19
36
51
23
17
—
26
—
19
61
—
24
—
—
17
6
13
22
15
24
30
—
—
33
46
22
24
46
—
23
22
1
1
1
0
0
0
Raw
Coal
.391.7%
.061.4%
0.4i0.1%
.66+1.2%
96011410
.20i0.1%
.03+.03%
.05+. 02%
96+47
55i38
0.73i.2%
0.45i.l%
0
0
0
0
0
0
0
0
0
0
0
0
.40+. 1
59+33
1.4t.4
17il2
2.7i3
1.3i0.8
4.2i2
14i8
10i9
2.7t2
1.8+2
1.4+.4
l.lt.4
1.81.9
185+66
3.7+3
—
l.lil
.19+. 2
4981175
5.7i2
9.7i3
.69+0.2
.171.07
.151.04
.60i0.2
.391.2
.071.02
.991.2
.131.05
.801.3
4. 1±1
2.01.9
.98i0.2
Western
Retention
MMF Percentage
56+20
76i58
71+77
61+69
7.8i6
17i5
—
31il6
—
1.8i2
0.42+.1%
0.42+.1%
0.031.03
7.3+6
0.291.2
2.3i2
1.1+.3
0.5i0.5
—
3.6i3
—
0.731.8
0.5+.3
0.391.2
1.8±2
—
—
—
—
0.381.2
—
13il4
1.31.7
1.7+1
0.211.1
0.051.02
—
—
0. 111. 04
0.02i.01
0.261.1
—
—
—
O.SOi.2
0.13±.l
0.4
0.7
2
0.4
0.8
0.9
—
6
—
3
58
93
8
12
21
14
14
38
—
26
—
27
28
28
163
—
—
—
—
34
—
3
23
18
30
29
—
—
28
28
26
—
—
—
40
13
*A11 values in ppm unless noted. Less than values were not included in calculation of means.
tlnternal surface area by C02 method (values in m2/g).
31
-------
TABLE 8. Identification of coal samples and gravity separations*
Analysis
number State
C18560
C18562 Illinois
C18563
C18564
C18565
C18566
C18567
C17001
C18090 Illinois
C18094
C18095
C18096
C18097
C18098
C18099
C16137
C18121 Illinois
C18122
C18123
C18124
C18125
C18126
C18127
C18128
C18841
C18892 West Virginia
C18893
C18894
C18895
C18896
C18897
C19824 West Virginia
C19827
C19828
C19829
C19830
C19831
C19832
Specific
Coal seam gravity fraction
Float-sink set No. 1
RAW
Herrin (No. 6) 28M x 0
1.29F
1.33FS
1.40FS
1.60FS
1.6S
Float-sink set No. 2
RAW
Davis 3/8 x 28M
1.28F
1.30FS
1.32FS
1.40FS
1.60FS
1.60S
Float-sink set No. 3
RAW
Herrin (No. 6) 3/8 x 28M
28M x 0
1.25F
1.29FS
1.33FS
1.40FS
1.60FS
1.60S
Float-sink set No. 4
RAW
Pittsburgh No. 8 3/8 x 28M
1.28F
1 . 30FS
1.40FS
1.60FS
1.60S
Float-sink set No. 5
Pittsburgh No. 8 RAW
1.28F
1.29FS
1.32FS
1.40FS
1.60FS
1.60S
Percentage of
raw coal
34.3
25.9
18.6
12.5
8.7
25.9
19.5
19.7
19.3
7.2
8.5
36.1
17.4
14.7
9.3
6.9
15.6
33.8
20.9
25.7
13.5
6.1
27.8
26.5
19.7
13.3
5.5
7.2
32
-------
TABLE 8. (Continued)
Analysis
number
C18820
C18890
C18891
C18883
C18884
C18885
C18886
C 18887
C18848
C18889
C18878
C18879
C18880
C18881
C18882
C19854
C19848
C19849
C19850
C19851
C19852
C19853
C19000
C19014
C19009
C19010
C19011
C19012
C19013
Specific
State Coal seam gravity fraction
Float-sink set No. 6
RAW
West Virginia Pocohontas No. 4 3/8 x 28M
28M x 0
.30F
.33FS
.40FS
.59FS
.595
Float-sink set No. 7
RAW
Alabama Blue Creek 28M x 0
1.30F
1.32FS
1.40FS
1.60FS
1.60S
Float-sink set No. 8
Montana Rosebud RAW
1.301F
1.32FS
1.32FS
1.40FS
1.60FS
1.60S
Float-sink set No. 9
RAW
Arizona Black Mesa Field 28M x 0
1.28
1.30FS
1.40FS
1.60FS
1.60S
Percentage of
raw coal
24.7
25.3
25.0
14.1
10.9
25.3
20.5
36.0
11.8
6.4
36.8
24.4
13.1
12.3
10.4
3.0
25.0
26.3
40.8
6.9
1.0
*For analytical results of concentrations of major, minor, and trace elements in the coal
fractions, see Gluskoter et al., 1977, p. 90-104, and Kuhn et al., 1978, p. 5-8.
33
-------
TABLE 9. Concentrations and organic affinities of elements for
sample C18560 from Herrin (No. 6) Coal Member in Illinois
Element
Al
Ca .
Fe '
K
Mg
Na
Ti
Si
Organic S
Total S
As
B
Ba
Be
Br •
Cd
Ce
Co
Cr
Cs
Cu
Dy
Eu
Ga
Hf
La
Lu
Mn
Ni
P
Pb
Rb
Sb
Sc
Se
Sm
Sr
Ta
Th
U
V
U
Yb
Zn
Organic "aw
affinity (%)
.30 1.40
.06 0.51
.06 2.60
.56 0.13
.27 0.06
.64 0.04
.29 0.06
.45 3.20
1.11 1.87
.45 6.45
.04
.77
.15
.87
'.92
.07
.07
.74
.77
.44
.66
.89
.67
. .15
.48
.04
.59
.06
.75
.03
.32
.45
.90
.57
.28
.39
.07
.44 '
.55
1.29
.97
—
.52
.04
coal
(ppm)
3.4
200
54
1.4
13.4
<0.1
25
7.2
21
2.0
13
1.2
.3
2.4
1.1
6.1
0.1
60
24
50
<1.0
23
0.5
4.1
4.3
0.9
33
0.2
3.6
1.9
36
0.6
0.8
57
Organic fractions
F/S ext* MMFt
(X) (ppm) (%)
0.10
0
0
0.04
0.003
0.01
0.13
0.017
2.33 J.81
1.1 1.81
0
57
2
0.6
12
0
0 -
1.7
20
0.2
3.3
0.8
0.1
0.3
0.1
0
0.03
0
5.9
0
0.3
0.3
0.4
0.8
0
0.2
0.8
0.05
0.8
2.7
35
—
0.2
0
(ppm)
41
25
66
<1
21
6
20
41
<.7
6.6
<2
0.03
3.3
<0.1
1.7
.4
7
0.1
2.1
0.4
0.1
.7
0.1
0.7
<.01
0.3
<1
<1
<1
<1
.1
0.6
.3
0.4
1.5
0.1
1.0
0.1
3.5
0.1
0.2
1
*Extrapolation of float-sink data.
•(•Concentration in the acid demineralized residue of the 1.40 float
fraction of the coal.
34
-------
TABLE 10. Concentrations and organic affinities of elements for
sample C17001 from Davis Coal Member in Illinois
Organic fractions
Element
Al
Ca
Fe
K
Mg
Na
Si
Ti
Organic S
Total S
As
B
Be
Cd
Co
Cr
Cu
Ga
Mn
Ni
P
Pb
Sb
Se
V
Zn
Organic
affinity
.58
.63
.04
.63
.41
.76
.50
.76
1.09
.10
.05
1.05
1.03
.07
.65
.69
.56
.67
.35
.82
.75
.04
.68
.69
.60
.02
Raw
(X)
0.86
0.82
2.76
0.14
0.02
0.048
2.08
0.06
1.51
4.14
coal
(ppm)
9.4
37
1.6
1.3
8.0
30
8.0
2.0
22
17
48
56
2.5
3.3
62
170
F/S
(X)
.32
.16
0
.05
.01
.009
.54
.03
1.2
0.1
ext*
(ppm)
0
30
2.7
0
1.3
5.5
2.7
1.0
3.9
5.8
11
0
0.2
1.3
11.8
0
MM Ft
(%) (ppm)
125
67
64
31
95
25
197 '
19
1.57
1.57
<5
6.1
0.1
<0.1
<1
<5
1.8
0.9
0.7
<4 .
2.8 '
<1
0.6
<.5
1.6
<1
*Extrapolation of float-sink data.
tConcentration .in the acid demineralized residue of the 1.40 float
fraction of the coal.
35
-------
TABLE 11. Concentrations and organic affinities of elements for
sample C16137 from Herrin (No. 6) Coal Member in Illinois
Organic fractions
Element
Al
Ca
Fe
K
Mg
Na
Si
Ti
Organic S
Total S
As
B
Be
Cd
Co
Cr
Cu.
Ga
Mo
Mn
Ni
P
Pb
Sb
Se
V
Zn
Organic
affinity
.10
.04
.16
.13
.32
43
.09
.16
1.15
.54
.05
.94
.88
.04
.35
.37
.26
.41
.52
.04
.36
.16
.05
.67
.39
.58
.04
Raw
(%)
1.12
0.73
1.70
0.18
0.05
0.02
2.48
0.07
1.95
3.25
coal
(ppm)
27
100
2.8
—
8.0
28
20
4.2
9.0
71
30
21
72
4.2
2.4
32
2700
F/S ext*
(%) (ppm)
0
0
0.12
0.004
17
140
0
0.005
1.58
1.56
0
86
2.0
0
1.1
4.3
2.1
1.1
.4
0
5.2
0
0
1.0
0.7
13
0
MMFt
(%) (ppm)
60
13
55
1.3
43
6.6
36
20
1.12
1.12
<.5
6.6
0.03
0.1
0.2
5.2
4.1
0.7
<1
.3
<3
1.4
<1
0.6
0.4
- 8.5
3
*Extrapolation of float-sink data.
tConcentration in the acid demineralized residue of the 1.40 float
fraction of the coal.
36
-------
TABLE 12. Concentrations and organic affinities of elements for
sample C18841 from Pittsburgh (No. 8) seam in West Virginia
Organic fractions
Element
Al
Ca
Fe
K
Mg
Na
Si
Ti
Organic S
Total S
As
B
Ba
Be
Br
Cd
Ce
Co
Cr
Cs
Cu
Dy
Eu
Ga
Hf
La
Lu
Mn
Ni
P
Pb
Rb
Sb
Sc.
Se
Sm
Sr
Ta
Tb
Th
U
V
Yb
Zn
Organic
affinity
.34
.50
.30
.12
.49
.54
.12
.05
1.07
.71
'.25
.81
.72
.53
1.00
.66
.41
.53
.40
.09
.47
.65
.54
.53
.30
.45
.26
.43
.44
.71
.62
.20
.41
.40
.36
.44
1.03
.24
.33
.23
.79
.48
.32
.42
Raw coal
00 (ppm)
1.20
0.53
1.70
0.19
0.04
0.060 .
2.30
0.06
2.51
5.02
3.2
120
72
0.7
10
<.l
15
3.3
15
1.0
5.1
1.5
0.3
4.3
0.7
8.7
.1
20
6.3
59
3.0
13
0.2
2.6
1.1
1.5
110
0.8
0.1
2.9
0.7
26
0.4
14
F/S ext*
(%) (ppm)
0.14
.10
0
0
.011
.016
0
0
2.6
2.4
0
45
35
0.2
6.8
.1
1.2
0.6
3.2
0
1.3
0.5
0.1
1.0
0.1
1-7
5.6
1.4
28
1.5
.8
0.02
0.3
0.04
0.21
66
0.02
0.04
0.4
5.0
0.01
1.5
MMFt
(X) (ppm)
280
210
240
0.7
7
6
64
94
2.28
2.28
<.5
24
10
.01
3.8
<0.1
3.3
0.8
8.6
0.03
<0.3
—
.1
1.7
.1
2.4
0.05
3.7
3
2 '
<1
<1
0.1
1.3
0.4
0.6
—
<.01
<.07
0.6
0.1
4
0.2
1.0
*Extrapolation of float-sink data.
•(•Concentration in the acid demineralized residue of the. 1.40 float
fraction of the coal.
37
-------
TABLE 13. Concentrations and'organic affinities of elements for
sample C19824 from Pittsburgh (No. 8) seam in West Virginia
Organic fractions
Element
Al
Ca
Fe
K
Mg
Na
Si
Ti
Organic S
Total S
As
B
Ba
Be
Br
Cd
Ce
Co
Cr
Cs
Cu
Dy
Eu
Ga
Hf
La
Lu
Mn
Mo
Ni
P
Pb
Rb
Sb
Sc
Se
Sm
Sr
Ta
Tb
Th
U
V
W
Yb
Zn
Organic
affinity
.62
.04
.17
.10
.04
.71
.39
.58
1.15
.81
.11
1.14
.90
.77
1.02
.09
.68
.79
.58
.28
.49
.67
.67
.79
.40
.68
-'— .62
.06
.04
.62
.68
.04
.18
.37
.67
.53
.72
.94
.51
.90
.62
.74
.57
.67
.74
.31
Raw coal
W (ppm)
1.02
1.61
1.12
0.102
0.16
0.068
1.95
0.06
1.10
2.23
3.9
82
130
0.4
12
0.2
16
2.2
14
0.8
8.6
0.8
0.2
2.6
1.0
5.7
.1
35
1.7
9.0
103
25
9.5
1.6
2.3
1.6
0.9
143
.2
0.1
2.1
0.6
17
0.3
0.3
10.3
F/S ext*
(%) (ppm)
0.43
0
0
0
0
0.036
0.33
0.023
1.67
1.65
0
86
100
0.3
12
0
6.2
1.5
5.0
0.1
2.1
0.4
0.1
2.1
0.2
3.0
0.03
0
0
2.6
42
0
0
0.2
1.1
0.7
0.5
0.1
0.04
0.1
0.7
0.7
6.6
0.2
0.2
0.8
MMFt
W (PPm)
41
30
80
2.5
<20
8.8
40
11
1.18
1.18
.3
— ..
27
0.1
12
<.l
2.5
0.2
2.0
0.03
1.5
0.5
0.1
1.4
0.6
2.6
0.02
0.7
<0.2
2
<5
<1
<1
0.8
0.1
0.5
0.5
24
0.1
0.04
1.1
0.1
2.7
<0.9
0.1
1
*Extrapolation of float-sink data.
•(•Concentration in the acid-demineralized residue of the 1.40 float
fraction of the coal.
38
-------
TABLE 14. Concentrations and organic affinities of elements for sample C18820
from Pocahontas (No. 4) seam in West Virginia
Organic fractions
Element
Al
Ca
Fe
K
Mg
Na
Si
Ti
Organic S
Total S
As
B •
Ba
Be
Br
Cd
Ce
Co
Cr
Cs
Cu
Dy
Eu
Ga
Hf
La
Lu
Mn
Ni
P
Pb
Rb
Sb
Sc
Se
Sm
Sr
Ta
Tb
Th
U
V
W
Yb
Zn
Organic
affinity
.25
.53
.67
.12
.37
.50
.11
.29
1.18
.82
.07
.47
.77
.87
1.07
.63
.50
1.16
.38
.14
.55
.60
.57
.49
.24
.41
.52
.40
.99
.65
.38
.12
.55
.48
.46
.46
.89
.28
.54
.29
.40
.56
.80
.60
.52
Raw coal
(%) (ppm)
1.40
0.56
0.90
0.21
0.06
0.070
2.50
0.12
0.51
0.80
15
8
220
0.1
22
0.1
33
7.0
17 . .
1.9
20
2.0
0.5
4.0
1.3
20
0.1
14
12
26
1.6
16
4.6
3.0
5.8
2.7
120
0.1
0.3
5.9'
1.1
22
0.5
0.7
11
F/S ext*
(%) (ppm)
0.15
0.15
0.43
0
0.011
0.012
0
0.021
0.58
0.56
0
2.1 .
120
0.9
28
0.1
9.4
6.7
3.2
0
8.3
0.9
0.2
1.5
0.1
4.9
0.04
3.8
11
16
1.1
0
0.4
0.9
1.6
0.7
78
0.03
o.i-
0.5
0.3
15
0.5
0.3
2.2
MMFf
(%) (ppm)
169
74
72
<10
18
0.5
56
19
0.47
0.47
<0.5
9.7
33
0.1
16.
<0.1
4.5
5.4
6.3
0.2
6:5
0.9
0.2
0.7
0.2
5.0
0.05
0.5
<5
0.1
<1
<1
.6
2.0
1
0.9
50
0.1
<1
1.1
0.2
1.5
0.1
.2
<1
*Extrapolation of float-sink data.
tConcentration in the acid demineralized residue of the 1.40 float fraction of the coal.
39
-------
TABLE 15. Concentrations and organic affinities of elements for sample C18848
from Blue Creek seam in Alabama
Organic fractions
Element
Al
Ca
Fe
K
Mg
Na
Si
Ti
Organic S
Total S
As
B
Ba
Be
Br
Cd
Ce
Co
Cr
Cs
Cu
Dy
Eu
Ga
Hf
La
Lu
Mn
Ni
P
Pb
Rb
Sb
Sc
Se
Sm
Sr
Ta
Tb
Th
U
V
W
Yb
Zn
Organic
affinity
.40
.34
.44
.12
.07
.20
.17
.54
1.08
1.08
.05
.37
.62
.76
1.20
.45
.64
1.08
.60
.10
.78
.78
.78
.64
.44
.74
.69
.05
1.01
.60
.68
.10
.64
.53
.58
.66
.80
.34
.66
.43
.71
.75
.70
.56
.21
Raw coal
(%) (ppm)
1.90
0.35
0.70
0.28
0.05
0.030
2.80
0.15
0.50
0.55
1.8
15
230
0.7
2.5
<0.1
30
9.4
21
2.3
12
2.1
0.4
6.3
1.2
18
0.1
13
11
190
12
18
0.8
4.3
3.0
2.8
130
1.1
0.2
5.4
0.9
54
0.4
0.9
2.0
F/S ext*
(%) ' (ppm)
0.25
0.037
0.14
0
0
0
0
0.04
0.53
0.56
0
0.8
76
0.4
2.5
0.05
14
7.9
7.1
0
8.0
1.5
0.2
2.6
0.3
9.6
0.04
0
9.9
90
1.9
0
0.2
1.2
0.9
1.0
54
' 0.04
0.2
0.6
0.8
29
0.3
0.2
0
MMF1"
(%) (ppm)
240
48
54
2.3
<20
<3
64
28
0.33
0.36
<0.5
5.1
20
0.05
1.7
<0.1
3.5
10
14
0.05
4.1
.7
0.1
1.7
0.3
2.8
0.1
<1
1
<4
<1 .
<1.
0.7
2.5
.4
0.1
13
<0.1
<.l
5
0.3
<5
0.1
.2
<1
*Extrapolation of float-sink data.
•(•Concentration in the acid demineralized residue of the 1.40 float fraction of the coal.
40
-------
TABLE 16. Concentrations and organic affinities of elements for sample C19854 from
Rosebud seam in Montana
Element
Al
Ca
Fe
K
Mg
Na
Ti
Si
Organic S
Total S
As
B
Ba
Be
Br
Cd
Ce
Co
Cr
Cs
Cu
Dy
Eu
Ga
Hf
La
Lu
Mn
Mo
Ni
P
Pb
Rb
Sb
Sc
Se
Sm
Sr
Ta
Tb
Th
U
V
W
Yb
Zn
Organic
affinity*
.18
.82
.02
.02
.97
.88
.15
.06
1.10
.74
.03
1.24
.02
.73
.99
.06
.89
.80
.09
.03
.44
.77
.89
.76
.39
.90
.68
.04
.83
.64
1.02
.04
.03
.95
..78
.05
.73
.98
.61
.79
.56
.58
.60
1.15
. .74
.02
Raw Coal
(%) (ppm)
1.15
0.97
0.47
0.079
0.44
0.019
0.05
2.41
0.62
.90
0.7
100
808
0.5
1.6
0.2
10.3
1.2
6.2
0.4
8.8
0.6
—
3.3
1.2
5.2
0.1
85
7.1
3.1
121
4.6
3.3
—
1.6
0.9
0.9
103
0.1
0.1
2.5
1.5
10.6
0.7
0.2
4.3
Ojganic
F/S Ext1
(%) (ppm)
0
0.43
0
0
0.32
0.009
0
0
0.53
0.59
0
115
0
0.1
5.0
0
5.3
0.6
0
0
1.2
0.3
0.1
1.7
0.2
3.1
0.02
0
2.6
0.8
95
0
0
0.5
0.7
0
0.3
94
0.5
0.5
0.6
0.2
2.3
.7
.1
0
fractions
MMFf
(%) (ppm)
20
20
35
<5
<20
15
4
30
0.56
0.46
<.3
—
40
0.03
4.5'
<0.1
3.3
1.5
0.6
<0.04
1.8
0.2
0.04
2.2
0.2
1.3
0.03
1.5
1.4
<2
<5
<1
<1
0.7
0.6
0.3
0.2
4.4
.1
0.05
.8
0.2
1.2
<.l
0.2
<0.3
*0rganic affinity calculated on unadjusted washability curve.
^Extrapolation of float-sink data.
•^Concentration in the acid demineralized residue of the 1.40 float fraction of the coal.
41
-------
TABLE 17. Concentrations and organic affinities of elements for sample.C19000
from Black Mesa Field in Arizona.
Organic fractions
• Element
Al
Ca
Fe
K
Mg
Na
Ti
Si
Organic S
Total S
As
B
Ba
.Be
Br
Cd
Ce
Co
Cr
Cs
Cu
Dy
Eu
Ga
Hf
La
Lu
Mn
Ni
P
Pb
Rb
Sb
Sc
Se
Sm
Sr
Ta
Tb
Th
U
V
W
Yb
Zn
Organic
affinity
.39
.82
.89
.53
.95
1.00
.33 .
.10
.95
.88
.11
1.09
.92
.79
.83
.99
.64
.83
.54
.03
.74
.82
.57
.38
.47
.58
.72
.53
.88
.94
.06
.40
.66
.64
.61
.47
.84
.39
.54
.38
.50
.74
.52
.75
2.2
Raw coal
(%) (ppm)
1.40
0.46
0.40
0.02
0.07
0.150
0.06
0.71
0.52
0.72
1.0
37
270
0.4
0.9
<0.1
6.0
0.8
3.5
0.1
4.7
0.6
0.2
2.3
0.6
6.0
0.1
1.4
1.5
120
<.7
1.2
0.4
1.3
1.6
0.8
200
0.1
0.1
1.4
<0.7
7.1
1.2
0.2
7.0
F/S Ext*
(%) (ppm)
0.12
0.65
0.28
0.007
0.064
0.153
0.007
0
0.41
0.32
0
37
220
0.4
1.3
0.1
4.6
0.6
1.3
0
2.4
0.5
0.05
0.4
0.3
2.1
0.04
1.1
1.2
96
0
0.3
0.1
0.7
0.7
0.2
130
0.03
0.05
0.4
0.4
8.7
0.1
0.2
2.3
MMFt
(%) (ppm)
187
200
225
<10
<20
1.4
54
53
0.32
0.32
0.2
5.3
15
0.03
1.0
<0.1
1.2
0.5
1.4
<0.05
<3
—
0.05
0.2
0.2
1.3
0.03
0.4
<1.5
<4
<1
<1
.2
0.4
0.6
• .3
—
—
<.05
0.6
0.05
<5
<.3
.1
<0.5
*Extrapolation of float-sink data.
Concentration in the acid demineralized residue of the 1.40 float fraction of the coal.
42
-------
The extrapolated values are thought to represent the theoretical con-
centration of an element in a coal when no mineral matter is present or, in
other words, the quantity of an element that is intimately associated with
the organic matrix.
EXCHANGEABLE AND SOLUBLE IONS
Results of analyses of raw coals and their residues, which have been
leached with ammonium acetate, are given in table 18. Comparison of the
two values (raw coal minus residue) is a good indicator of the potential
for removal of exchangeable ions and soluble elements from coal. However,
the data may be subject to some error when comparisons are made for inter-
pretive purposes with data in tables 9-17 because different samples of the
same coals were used in the two studies. The desirability of making this
comparison is discussed in the section on "Validity of Organically Associated
Elements," page 50.
MINERALOGY
The results of qualitative mineral analyses for 26 whole coals in this
study are presented in table 19. Certain mineral phases, such as kaolinite,
illite, expandable clays, calcite, pyrite, and quartz, are ubiquitous in these
coals. However, some regional differences in mineralogy related to deposi-
tional and geochemical environments can be observed and are in agreement with
the findings of previous workers (Rao .and Gluskoter, 1973; Q'Gorman and"
Walker, 1972; Miller and Given, 1978).
As a group, the western United States coals in this study have dis-
tinctively different mineral assemblages from the other two regions. Bassa-
nite.composes a major mineral phase in the low temperature ash of western
lignites and subbituminous coals; it forms during the low temperature ashing
process both by the dehydration of the mineral gypsum, when it is present,
and by the fixation of exchangeable calcium cations, which are common in
low rank coal containing organic sulfur (Miller and Given, 1978). The
exception in the group is a high volatile bituminous coal from Arizona in
which the level of exchangeable cations is quite low. Another major dif-
ference between western United States coals and the other two groups studied
is the predominance of very high intensity, well-crystalized kaolinite over
other clay minerals in the LTA. There are traces of barite, chlorite, and
aragonite in these coals.
Eastern United States and Illinois Basin coals are somewhat similar
mineralogically, although a higher frequency of iron carbonate minerals is
evident in the eastern coals studied. Pyrite content is likely to be highly
variable throughout both regions. The presence of the iron sulfates, szomol-
nokite and coquimbite, in these samples is primarily due to the oxidation of
pyrite during storage, although it is possible that limited quantities of
these sulfates can be produced in the low temperature asher. Detectable
amounts of epigenetic sphalerite are characteristic of northwestern Illinois
coals.
Nine of the 27 coals (see table 8) were studied in greater detail to
evaluate the distribution of the major mineral phases in the various specific
gravity fractions of each coal. Quantitative x-ray diffraction determinations
43
-------
TABLE
18. Comparison of concentrations
C18126
Si (%)
Al (%)
Fe (%)
Ca (%)
Na (ppm)
Mg (%)
K (%)
Ti (%)
P (ppm)
Mn (ppm)
S (%)
Cl (%)
As (ppm)
Ba (ppm)
Be (ppm)
Br (ppm)
Ce (ppm)
Co (ppm)
Cr (ppm)
Cs (ppm)
Cu (ppm)
Dy (ppm)
Eu (ppm)
Ga (ppm)
Hf (ppm)
La (ppm)
Lu (ppm)
Ni (ppm)
Rb (ppm)
Sb (ppm)
Sc (ppm)
Se (ppm)
Sm (ppm)
Sr (ppm)
Ta (ppm)
Tb (ppm)
Th (ppm)
U (ppm)
V (ppm)
W (ppm)
Yb (ppm)
Zn (ppm)
Pb (ppm)
Raw
coal
1.17
.73
.74
.08
240
.03
0.10
.06
14
10
3.3
.22
2.0
80
2.8
12.5
3.5
2.5
17.2
2.5
21
0.6
0.09
3.3
0.4
2.1
0.06
2.6
7.7
1.4
2.5
2.0
0.5
19
.12
.13
1.4
29
.2
.3
11
71 .
Leached
residue
1.15
.69
.76
.07
75
.02
0.10
.06
13
6.5
3.3
.02
1.9
70
2.7
5.6
4.3
2.1
17.9
0.6
23
0.6
0.09
3.0
0.5
2.3
0.10
2.9
7.8
1.6
2.7
1.7
0.4
18
.11
.14
1.6
1.4
28"
.3
.4
11
71
C18841
Raw
coal
1.22
1.01
1.3
.20
312
.03
.08
.04
48
12
5.0
.02
2.5
32
0.7
6.0
8.0
2.1
9.8
0.3
5.1
0.6
0.15
2.8
0.3
3.8
.07
14
7
.16
1.8
0.9
0.7
105
.07
.17
1.1
.8
18
.5
.3
12 -
5
Leached
residue
1.21
.95
1.1
.12
180
.02
.08
.04
51
io
4.8
.01
2.1
28
0.7
4.2
6.5
1.6
8.5
0.3
5.0
0.6
0.14
2.6
0.3
3.8
.05
14
3
0.14
1.6
0.8
0.7
32
.07
.13
1.0
.5
18
.5
.3
14
4
of minor
C18848
Raw
coal
. 1.72
1.44
.15
.11
170
.02
.16
.04
190
5.3
.92
.02
.5
154
0.7
3.2
22
8.5
17
0.7
12
1.2
0.4
4.0
0.8
11.5
0.11
15
6
0.6
3.7
2.0
1.6
122
.2
.26
2.9
2.2
52
.5
.7
13
12
Leached
residue
1.71
1.45
.15
.06
136
.02
.16
.04
204
4.6
.92
.01
.2
135
0.7
2.6
22
8.2
16
0.7
12
1.2
0.3
4.2
0.8
11.9
0.11-
17
7
0.6
3.7
1.1
1.7
120
.2
.30
2.9
1.2
53
.3
.7
13
11
and trace elements in coal and NH..AC extracted residue
C19000
Raw
coal
.75
.54
.18
.80
1520
.07
.009
.05
170
— ~
.84
.12
0.6
242
0.4
2.6
5.5
0.9
2.8
4.7
0.5
.11
1.3
.6
3.8
.07
2.4
— ,-
.2
1.2
1.4
.5
204
.10
.10
1.2
7
.3
3
.7
Leached
residue
.64
.55
.18
.51
62
.04
.009
.05
160
.86
.07
0.8
225
0.4
1.6
5.6
0.7
2.9
5.3
0.5
.11
1.3
.5
3.9
.05
2.3
.2
1.1
1.3
.5
200
.9
.16
1.2
.7
8
.3
.3
4.6
.5
C19824
Raw
coal
2.17
1.30
1.2
1.21
715
.07
.13
.07
118
32
2.29
.14
4.9
120
.3
10.5
11
2.1
16
7
8.6
.7
.2
2.8
.7
5.8
.08
.9
6.5
3.8
2.1
1.4
.8
130
.17
.15
1.8
1.1
17
.4
.4
11
25
Leached
residue
2.27
1.31
1.1
1.02
594
.04
.14
.18
106
36
2.32
.09
5.0
110
.3
9.3
10
2.1
17
5
8.2
.2
.2
2.7
.6
5.8
.07
9.4
9
3.2
2.1
1.3
.8
130
.12
.15
1.7
.5
16
.2
.3
11
28
C19854
Raw
coal
2.30
1.35
.41
0.97
208
.23
.09
.06
117
105
.81
.02
1.4
800
.5
.6
8.3
1.1
6.0
3
8.8
.6
.12
3.0
.9
5.0
.06
3.4
4.7
.6
1.4
.8
.6
103
.17
.13
2.1
1.5
10
.8
.3
7.4
6
Leached
residue
2.31
1.37
.47
0.26
107
.06
.09
.07
124
74
.83
.01
1.1
700
.5
.4
9.5
1.3
6.0
3
1 9.1
.5
.13
3.8
1.0
5.5
.07
1.5
4.7
.7
1.5
.8
.8
50
.15
.13
2.4
1.7
10
.9
.4
5.8
6
C18440
Raw
coal
.88
.85
.31
2.33
3640
.26
.06
.02
236
59
.67
.02
2.1
500
.5
3.1
8.3
1.0
3.2
.14
2.8
.3
.11
2.3
.8
5.7
.07
4
2.7
.9
1.1
.7
.4
240
.12
.10
1.6
1.6
6
1.3
.3
14
5
Leached
residue
.90
.76
.33
0.85
56
.05
.04
.02
171
43
.69
.01
2.4
400
.5
1.4
8.0
.9
3.4
.13
2.7
.5
.10
2.3
.8
6.0
.05
1.5
1.9
.8
1.2
.7
.5
100
.13
.09
1.6
2.0
6
1.5
.3
20
7
-------
TABLE 19. Results of qualitative mineral analysis of low-temperature ashes.
> -i-
C 10 I-
(Q ^~ O
O. O i—
X -C
UJ <_>
X
X
X
X
X
X
X
X
X
X
X
O)
4J Q> fl) Q>
•r- +J •!- -r- •!-
O -r- E i. t-
o u o o> oi
in r- r- -a it
3 IO O -i- C
s: <-> a to «t
1
X
X .
X
X
X
X
X
X
X
X
X
X
ai a)
. 4-> •<->
'c -r- O
*J 01
a* T- a) m
<-> ^ -M at to
•f- O T- •*-> ^»
&- c .a -r- o
aii— EWECNO
f— O -i- +•> 3 «*»•!-
j= o CT i- o. m 10 10
a-Noia^ni^i—
COOOOCQCJCQO-Q.
XX X
XX X
XXX X
X X
X X
X X
X XX
XX XX
X XX
XX XX
x x
X X XX
X X
XX X
ie
F-
O T-
•M n)
s- a.
0 *£
X
Eastern United States
C-18820* X X
C- 18824 X
C-18841* X X
C-18844 X X
C- 18848* X
C- 19824* X X
X
x ..
X
X
X XX
X
X X
XX X
X X
X
X
X
X
X
X
X
X
X
X X
X
X X
X
X
Western United States
C- 18440 X X
C- 18445 X
C- 18457 X
C-18816 X
C-19000* X
C- 19854* X . X
X
X
X
X
X X
X
X
X
X
X X
X
X
X
XX XXX
X XX
X X
X X
X
X XX
*Quantitative mineral analysis of washed fractions of these coals are presented in subsequent
tables.
-------
of pyrite, calcite, quartz, and other major minerals present in the washed
fractions are given in table 20. The relative percentages of pyrite, calcite,
quartz, and most of the minor mineral's in the LTA generally increase in the
heavier washed fractions as the relative percentage of total clays in each
fraction decreases. These trends are especially evident in coals having
numerous mineralized bands and partings or.in coals having heavy epigenetic
mineralization in cleats and .fractures. Minerals such as these are easily
removed during normal coal cleaning operations. In sets of washed coals
having an inverse mineral distribution in the LTA, for example, siderite and
ankerite in set 6 and bassanite in set 8, the data indicate that these min-
erals are finely disseminated in the coal and that they are intimately associ-
ated with the macerals rather than being in cleat fillings.
Examples of washability curves prepared from the mineral data in table 20
are shown in figure 9 for the Herrin (No. 6) Coal. These curves demonstrate
that a large portion of the pyrite and calcite in this coal can be concentrated
and removed through physical cleaning methods; removal of quartz and clay min-
erals is less efficient than removal of heavier minerals. Mineral washability
curves for the remaining washed coals display similar results.. Yancey and
Geer (1962) suggest that the retention of clay minerals in the lighter frac-
tions is due to the buoyant effect of imbedded coal in shale particles. The
aggregation of quartz and clay minerals in detrital mineral bands found in the
coal typically produces similar washing characteristics for the two groups of
minerals.
Results of clay mineral analysis of the <2 ym fraction of the low temper-
ature ash for 2 sets of,washed coals are given in table 21. Because of the
inherent problems involved with clay mineral preparation and analysis, these
data are given to indicate general trends and are not absolute. Both coals
were found to contain higher propor-
tions of kaolinite in the lighter frac-
tions and increased amounts of illite
and expandable clays in the 1.60 frac-
tion. These data show that a dual pop-
ulation of clay minerals may be present
in the coal. Shale particles having a
specific gravity approximating 2.3—
20'40'eb'so'160 derived from partings, joint fillings,
and other rock materials mined with the
coal—are concentrated in the heaviest
fraction. This shale component con-
tains an increased amount of expandable
clays and lesser amounts of kaolinite.
The clay minerals associated with the
coal macerals in the lighter washed
fr;actipn's^ma^bjL principal 1 y composed
of autfngenic kao 1 inite and moderate
amounts of illite and other clays. The
apparent distribution of all the clay
minerals present in the washed fractions
may also be affected by the disintegra-
tion of shale particles and their suspen-
sion in the washing medium; subsequently,
lighter gravity fractions may be
20 40 60 80 100
Percentage of recovery
Percentage of recovery
2.8.
2.4-
1.9-
1.4-
0.9-
0.5-
0.0'
QUARTZ
8.1
6.8-
5.4-
4.1-
2.7-
1.4-
0.0
TOTAL
CLAYS
0 20 40 60 80 100
Percentage of recovery
0 20 40 60 80 100
Percentage of recovery
HERRIN (No. 6) COAL SEAM, ILLINOIS
Figure 9. Mineral distributions in a single sample of the Herrin
(No. 6) Coal Member, Illinois. (C18560)
46
-------
TABLE 20. Results of.mineralogical analysis
Sample No.
Set 1
C18560
C18562
C18563
C18564
C18565
C18566
C18567
Set 2
C18090
C18094
C18095
C18096
C18097
C18098
C18099
Set 3
C18121
C18122
C18123
C18124
C18125
C18126
C18127
C18128
Set 4
C18841
C18892
C18893
C18894
C18895
C18896
C18897
C18898
Fraction
Raw Coal
28M x 0
1.29F
1.33FS
1.40FS
1.60FS
1.60S
3/8 x 28M
1.28F
1.30FS
1.32FS
1.40FS
1.60FS
1.60FS
3/8 x 28M
28M x 0
1.25F
1.29FS
1.33FS
1.40FS
1.60FS
1.60S^
Raw Coal
3/8 x 28M
28M x 0
1.29F
1.32FS
1.40FS
1.59FS
1.59S
Average
Recovery
co
—
—
34.3
25.9
18.6
12.5
8.7
—
25.9
19.5
19.7
19.3
7.2
8.5
—
—
36.1
17.4
14.7
9.3
6.9
15.6
—
—
—
33.8
20.9
25.7
13.5
6.1
mineral
LTA
m
20.37
25.17
6.10
9.81
17.62
26.48
77.80
15.80
3.61
5.56
6.67
12.74
23.06
73.53
26.28
28.23
3.83
5.01
8.18
14.86
25.92
88.40
14.50
13.96
15.38
3.89
7.87
11.87
22.43
63.79
percentages
Pyrite
a>
39
28
19
22
23
31
49
34
17
15
15
16
20
65
15
12
20
21
21
22
20
26
38
36
29
37
55
50
25
± 7.5% in
Calcite
a>
5
6
3
3
2
2
10
6
5
5
5
7
8
2
5
6
2
2
2
2
2
8
4
5
7
1
1
2
7
low temperature ash (LTA)
Quartz Siderite Ankerite
m (%> m
14
14
16
16
18
27
9
18
15
17 — —
18
20
21
7
14
13
ft ___ __
16
17
15
21
12
—
11
12
6
7
10
8
22
Bassanite Clays
(%) (%)
42
51
62
59
57
40
— 32
42
63
63
62
57
51
26
66
69
69
61
60
61
57
52
—
47
47
58
55
34
40
46
-------
TABLE 20. Continued
-p-
oo
Sample No.
Set 5
C19824
C19827
C19828
C19829
C19830
C19831
C19832
Set 6
C18820
C18890
C18891
C18883
C18884
C18885
C18886
C18887
Set 7
C18848
C18889
C18878
C18879
C18880
C18881
C18882
Set 8
C19854
C19848
C19849
. C19850
C19851
C19852
C19853
Set 9
C19000
C19014
C19009
C19010
C19011
C19012
C19013
Fraction
Raw Coal
1.275F
1.292F
1.32FS
1.40FS
1.60FS
1.60S
Raw Coal
2/8 x 28M
28M x 0^
1.30F
1.33FS
1.40FS
1.59FS
1.59S
Raw Coal
28M x 0
1.30F
1.32FS
1.40FS
1.60FS
1.60S
Raw Coal
1.301F
1.32FS
1.35FS
1.40FS
l.'60FS
1.60S
Raw Coal
28M x 0
1.28F
1.30FS
1.40FS
1.60FS
1.60S
Recovery
fm \
\»° /
_«
27.8
26.5
19.7
13.3
5.5
7.2
—
—
;
24.7
25.3
25.0
14.1
10.9
—
—
25.3
20.5
36.0
11.8
6.4
—
36.8
24.4
13.1
12.3
10.4
3.0
—
—
25.0
26.3
40.8
6.9
1.0
LTA
14.49
5.11
6.42
9.28
14.01
24.14
80.04
12.90
13.73
12.44
1.93
3.39
7.75
20.50
64.58
12.67
11.38
3.76
6.15
9.71
19.76
59.75
13.09
7.41
9.46
6.91
11.35
20.53
62.88
8.75
9.20
4.03
4.37
7.87
22.72
79.67
Pyrite
16
10
13
18
21.
30
14
3
3
2
2
3
3
3
5
<1
<1
<1
<1
<1
<1
<1
3
<1
<1
<1
<1
<1
28
1
1
<1
1
1
2.
2
Calcite
22
2
3
2
3
7
60
3
3
3
2
2
2
2
4
4
4
4
4
4
6
6
4
<2
<3
<3
<7
10
10
9
10
<1
10
10
8
6
Quartz
8
7
7
6
9
14
10
6
7
6
3
2
7
18
24
8
10
4
4
9
7
26
13
9
12
10
13
20
20
22
21
19
21
24
27
29
Siderite
—
—
—
—
—
4
4
4
9
8
4
1
0
2
3
1
3
3
6
9
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Anker ite
—
—
—
—
—
—
3
2
2
2
3
6
4
0
: —
Bassanite Clays
54
81
77
74
67
— 49
16
81
81
83
82
82
78
72
67
85
— 82
90
88
83
— 80
— 58
— 64
68
— 70
66
— 61
— 60
— 42
— 68
68
79
.68
65
63
— 63
-------
TABLE 21. Results of clay mineral analysis (<2 pm fraction of LTA) of two coals.
Kaolinite Mixed layer clays Chlorite
Sample Fraction
no.
Pittsburgh (No. 8),
West Virginia
Rosebud,
C19824
C19827
C19828
C19829
C19830
C19831
C19832
Raw coal
1.275F
1.292FS
1.32FS
1.40FS
1 . 60FS
1.60S
26
20
21
21
21
25
33
47
60
65
62
55
38
19
27
20
14
17
24
37
48
Montana
C19854
C19848
C19849
C19850
C19851
C19852
C19853
Raw coal
1.301F
1.32FS
1.35FS
1.40FS
1.60FS
1.60S
17
17
12
16
17
20
28
64
68
71
77
71
67
56
11
5
9
7
12
13
16
8
0 10
8
—
— •
—
— •
contaminated. Although the effect would be much more pronounced in a water-
based medium, it is not evident to what degree this type of contamination
may be exhibited by the samples studied.
49
-------
SECTION V
DISCUSSION
VALIDITY OF ORGANICALLY ASSOCIATED ELEMENTS
The two methods for determining organically associated elements
(described in Section 3) yield values that are in substantial agreement for
the estimation of many organically associated elements in coal. Usually,
agreement is best where analytical values are higher and most reliable.
The poorest agreement was obtained for B, V, P, Ba, Sr, and Be.
In the last two columns of tables 9 through 17, the values determined
in the mineral-matter-free coal material may be compared with the values
obtained by extrapolation of adjusted coal washability curves to 0 percent
coal recovery. The relationship between these two sets of values for
organic sulfur in 9 coals is summarized graphically in figure 10. Figures
11 through 14 are typical plots of trace-element concentrations (float/sink
extrapolated vs. mineral-matter-free) in each of four coals. (For clarity
not all elements determined have been plotted.) Figures 11-14 also contain
a line for the case X = Y (i.e., a one to one correspondence of concentra-
tions) and lines for plus and minus 50 percent limits of X = Y.
For the most part, the two sets of values compare well; however, it is
recognized that the demineralization procedure may alter coal microporosity
(Majahan and Walker, 1979). Also, organic molecules, chelated elements, and
exchangeable ions may be removed through oxidation or dissolution. (Exchange-
able ions are also sometimes cited as being organically associated.) Despite
the use of HN03, which was used for the extraction of pyrite, the analytical
data in table 3 and figure 10 show that very little organic sulfur is
removed by the acid treatment; this suggests that the "coal molecule" itself
has not been significantly altered. Furthermore, the favorable comparison
between results of analyses of chemically-treated (MMF) coal and the results
obtained by extrapolating data from float-sink washability studies, where
removal of chelated elements is much less likely to occur, indicates that
concentrations of chelated elements, if indeed they are such, are not
altered sufficiently by acid extraction to be of major concern in most bitu-
minous coals.
Nevertheless, some large variations in the two sets of data remain.
For example, the extrapolated value for Na from adjusted float-sink data
was 0.15 percent for C-19000 (table 17), and the concentration of Na in the
mineral-matter-free material (MMF) was only 1.4 ppm. Major variations also
exist in some coals for Ba, B, Ca, and Sr; but data in table 18 indicate that
these elements are present in exchangeable or soluble form. An example of
this effect is shown in figure 15 where the exchangeable and soluble Ca in
Rosebud seam coal is approximately equal to the difference between the
50
-------
0.5 1.5 2.5
% Organic sulfur (extrapolated float/sink data)
ISGS 1980
Figure 10. Comparison of independently determined concen-
trations of organic sulfur in nine coals.
0.1
0.2 0.4 0.6 1 2 4
Extrapolated float/sink data (ppm) •
6 10
ISGS 1980
Figure 11. Comparison of independently determined concen-
trations of organically associated trace elements
in the Davis Coal Member, Illinois (C17001).
0.1
0.1
0.2 0.4 0.6 1 2 4 6 10
Extrapolated float/sink data (ppm) ISGS i960
0.2 0.4 0.6 1 2 4 6 10
Extrapolated float/sink data (ppm) ISGS 1980
Figure 12. Comparison of independently determined concen-
trations of organically associated trace elements
in the Pittsburgh No. 8 seam. West Virginia (C19824).
Figure 13. Comparison of independently determined concen-
trations of organically associated elements in the Rose-
bud Coal, Montana (C19854).
51
-------
float-sink extrapolated and mineral -
matter-free material values. (Stron-
tium in figure 13 is probably another
such example.) In the case of B
(figs. 11 and 14), high concentra-
tions from extrapolated float/sink
data relative to the mineral-matter-
free values, could be due to loss of
B as BF3 from the latter during acid
digestion.
The ion exchange data on some
elements, such as Ca in three differ-
ent coals shown in figure 15, help
explain most of the differences ob-
served between extrapolated values
(zero percent recovery) derived from
washability data and mineral-matter-
free values (acid extracted). Like-
wise magnesium is either soluble or
undergoes exchange reactions. This
is especially apparent in the west-
ern and low rank coals where more
than 70 percent of the total con-
centrations of both Ca and Mg were
removed. Sodium values indicate
0.1
0.2
0.4 0.6 1 2
Extrapolated float/sink data (ppm)
ISGS 1980
Figure 14. Comparison of independently determined concen-
trations of organically associated trace elements in
the Herrin (No. 6) seam coal, Illinois (C16137).
1.4
1.2-
1.0-
0.8-
0.6-
0.4-
0.2-
0.0
1.21
1.06
i
.10
.97
.53
.28
I
Whole coal
Residue
Extract
.09
Pittsburgh No. 8 seam, Rosebud seam.
West Virginia Montana
Blue Creek seam,
Alabama
ISGS 1980
Figure 15. Elemental concentration of calcium in ammonium acetate (ion-exchanged)
samples.
52
-------
nearly total exchange or solubility in all cases but one. The exception
is coal C-19824, which is unique in that 95 percent of the internal surface
area consists of relatively small micropores less than 5 microns in size.
It is suspected that pore size is a contributing factor in exchange or
solubility reactions for both Na and Cl and probably for other elements
as well.
The data in table 18 show that no significant quantity of Al, Si, P,
S, K, Fe, V, Ti, Ni, Cu, Zn, As, Br, or Pb are attached to the coals in an
exchangeable form or occur as a mineral that is soluble in the exchange
medium used (ammonium acetate). Thus exchangeable ions, which are not
removed during float-sink procedures, remain with the coal organic fraction
and tend to increase organic affinities of these elements. The acid extrac-
tion procedure, however, removes the exchangeable and/or soluble ions
attached to surfaces of the polymerized coal.
This evidence suggests that exchangeable ions may be contained in
associated ground water after initial polymerization has taken place—perhaps
even being a result of present-day conditions. The amount of surface area
made available to exchange reactions through grinding of coal is a very
small percentage of the actual surface area that would be present if the
material were totally depolymerized. These data indicate that virtually
all of the.exchangeable elements can be removed by the acid treatment. It
seems likely that adsorption occurs on the surfaces of the coal particles
and pores.
The same logic applies to elements that may be chelated with organic
material. If major portions of such elements can be removed, they probably
come from the available surface area, and chelation probably occurred after
the initial polymerization had taken place, and the coal structure had become
at least partially fixed.
While some disagreement exists in the values derived from the two inde-
pendent procedures for investigating elemental occurrence in coal, an account-
ing of these differences can be logically made. Moreover, agreement of trace
element concentrations, determined in acid-extracted mineral-free coal and
the concentrations calculated from adjusted washability curves, is suf-
ficiently good to permit their use as estimates of absolute quantities of
elements associated with coal organic material. These concentrations, for
the most part, are relatively low.
VARIABILITY OF ORGANICALLY ASSOCIATED ELEMENTS
Table 6, which compares elemental concentrations of the raw coal and the
the mineral-matter-free material, illustrates the large amount of variability
among coals. For example, in two high-rank eastern coals, the retained
cobalt is 72 percent in sample C-18820 but only 10 percent in C-19824. A
different effect can be shown for titanium; a retention of about 200 ppm
results in a percentage of 16.6 percent in C-18820, while a retention of
only 39 ppm in C-18440 results in a slightly higher 19.5 percent of titanium
remaining in the demineralized material. Therefore, knowledge of only the
total concentration of an element in a coal without knowledge of its organic
affinity is of little use in estimating the percentage associated with
organic matter. Table 7 gives the mean retention percentages of each organ-
ically associated trace element for each of the geographical regions studied.
53
-------
The degree to which coals in this study are representative members of
their respective regions is illustrated in table 22. Predicted concentrations
of an element in mineral-matter-free (demineralized) material were calculated
by multiplying the mean values for each element in whole coal (given in
Gluskoter et a'l. [1977], tables 8 through 10) by their respective mean
retention factors found in this study (table 7). Agreement between the
mean of predicted values and mean of determined values for the limited
number of samples included (24) is generally very good. Poor agreement.
occurs particularly for elements where the uncertainty for retention values
is greatest, i.e., at low concentrations.
Table 7 summarizes the mean elemental concentrations in coals for the
three geographical regions. The table presents evidence that for some ele-
ments greater variations in concentrations occur within a geographical area
than between such areas. Especially for whole coal, the standard deviations
within a single seam can exceed the mean concentrations in some instances
(see also Gluskoter et al., 1977, p. 121). For example, in the Herrin
(No. 6) coal seam (see tables 1 and 6), both the inorganic and the organic
components vary widely. Such differences demonstrate the need for each coal
to be considered on an individual basis.
Perhaps a better overall perception of the variability of organically
associated elements can be gained from the data in table 23. The total mean
retention percentages for all elements are combined, and the summation of
all element concentrations have been calculated for each demineralized coal
(values do not include sulfur). No relationship was observed between data
concerning ash content of the whole coals and other data in table 23.
Despite the apparent consistency in total mean retention percentages, large
standard deviations indicate wide concentration variations of the organically
associated elements within regions. Further, correlations made between all
pair combinations of organic affinities for Illinois No. 6 coal indicate
that knowledge of the organic association of one element is of little value
in predicting the organic association of other elements.
There is also an apparent lack of correlation between the residual
trace element concentration and the internal surface area of coal (table 23,
last column). If this characteristic of coal organic matter had significantly
affected results of the demineralization procedure, i.e., influenced extraction
of certain elements, correlation between surface area and the percentage of
trace elements removed should have been observed. This evidence indicates
that most organically associated elements are actually contained within the
polymerized structure of the coal. Minerals and exchangeable ions or, per-
haps, chelated elements on the surfaces of the coal particles are the mat-
erials thought to be removed by acid leaching.
COMPARATIVE DATA
Table 24 shows some of the relationships between the organically associ-
ated elements in coal and concentrations of the same elements in plant
material. This table presents the overall mean concentrations of the organi-
cally associated elements from this study, mean plant values compiled by
Siegel (1974), the mean crustal abundance of elements compiled by Mason
(1958), and certified values for the orchard leaves samples of the National
Bureau of Standards (SRM 1571). For the latter, additional values determined
at the Illinois State Geological Survey have been added. A few mean values
54
-------
,TABLE 22. Prediction of mean elemental concentrations in mineral-matter-free coal
for three basins.
All values ppm unless noted
Illinois
Element
Si
Al
Fe
Ca
Na
Mg
K
Ti
P
Mn
S
Organic S
Be
B
Sc
V
Cr
Co
Ni
Cu
Zn
Ga
As
Se
Br
Rb
Sr
Mo
Cd
Sb
Cs
Ba
La
Ce
Sm
Eu
Tb
Dy
Yb
Lu
Hf
Ta
W
Pb
Th
U
Predicted
mean*
(114)
72
72
100
67
10
45
17
24
5.8
1.06
1.6%
1.6%
0.05
17
.49
4.5
4.5
.80
6.1
3
15
1.9
0.7
0.3
8.5
1.1
5.6
.65
.37
.44
.08
6
0.9
1.4
.4
.05
.06
.34
0.14
.02
.08
.04
.21
.52
.28
Actual
meant
(15) (W)
65
74
76
50
7.9(13)
47(12)
11(9)
31
4.3(14)
1
1.6%
1.6%
.05
8
.53
5.5(13)
6(14)
.45(14)
5.1(7)
4(12)
2.7(3)
0.6(14)
0.2(2)
0.4(14)
7.7
3(1)
5.7(9)
.87(4)
.67(4)
.38(12)
.06(8)
3.3(11)
0.9
1.5
.3
.06
.09(6)
..28(10)
0.14
.03(12)
.11(13)
.05(5)
.38(7)
<
.55
.22(10)
Eastern
Predicted
mean
(23)
56
170
150
70.5
16
42
2.5
72
6
1.8
1.2%
0.86%
0.09
17
1.3
7
7
4
4
3
<
1.7
1.7
0.9
9 .
<
27
<
<
0.4
0.1
28
3.7
4.2
.73
.19
.10
.94
0.36
.08
0.29
0.10
0.20
1.2
0.3
Actual
mean
(6) (IV)
60
144
106
71
10(5)
25(3)
1.8(3)
76
2.8(4)
2.4(5)
1%
.98%
.06
14
1.3
9.3
7
3.5
2.8(5)
4
<
1.1
.3(1)
0.6
9.7
<
29(3)
<
<
.4
.08(4)
20
2.7
3.2
.54
.12
.04(1)
.66(3)
0.23
.06(5)
.29
.09(3)
.26(4)
<
2.6
.27(4)
Western
Predicted
mean
(28)
85
100
106
170
28
14
3
45
3.9
1.96
0.45%
0.53%
0.05
9
0.4
3
1.6
0.6
<
2
<
0.9
0.9
0.4
3.6
<
8
0.4
<
0.3
0.07
15
1.1
1.9
0.2
0.06
0.08
0.22
0.11
0.02
0.21
0.08
0.16
0.76
0.20
Actual
mean
(6)(ff)
56
76
71
61
7.8
17(3)
<
31
2.5(2)
1.8
.42%
A2%
.03(5)
7
.3
2.3(5)
1
.5
<
4
<
0.7
.5(4)
0.4
1.7
<
4(2)
1.4(1)
<
.38
.01(1)
13
1.3
1.7
.21
.05
.05(2)
.19(2)
0.1
.02(5)
.26
.09(2)
.22(2)
<
.8(5)
.13(5)
*Mean percentage retention (table 7) times mean elemental concentration (Gluskoter et al., 1977).
tMean elemental concentration determined (table 7).
55
-------
TABLE 23. Total retention percentages of elements and concentration summations for
demineralized coal and ash or mineral-matter content for whole coal
Coal sample
EASTERN
C 18820
C 18841
C 18848
C 18844
C 19824
C 18824
Mean
Total mean
retention*
(%)
22±21
17+15
20±20
22±19
26+31
20+16
Number of
elements
for meant
33
29
26
26
33
30
Sum. of
elements
determined
(ppm)
735
980
514
510
296
418
575.5±245
High-temp.
ash
(%)
11.5
10.2
11.6
8.3
11.0
12.5
10.811.4
Low- temp.
ash
(%)
12.9
14.5
12.7
10.4
14.5
14.7
13.311.7
Surface area
CO
(m2/g)
327
53
98
56
68
112
WESTERN
C 18816
C 19000
C 19854
C 18440
C 18445
C 18457
16+20
21117
'30+36
19+19
19+21
21+19
Mean
28
24
30
28
26
29
273
756
191
305
272
294
348.5+204
9.0
7.0
11.6
9.8
7.5
6.3
8.512
10
8
13
14
10
10.9+2.5
*Except sulfur.
"("Number of elements used to determine the mean.
277
240
236
147
232
219
ILLINOIS
C 14684
C 15999
C 16543
C 16993
C 17001
C 18126
C 16317
C 18304
C 18320
C 18368
C 18560
C 18571
C 18704
C 18748
C 18857
Mean
17115
17115
12+14
14+20
21124
11+11
18+18
14+12
17+17
15+21
14120
14+15
12113
16117
14+12
33
34
34
31
28
33
29
31
31
31
31
25
31
33
26
448
415
332
415
681
277
340
719
309.
265
253
377
423
287
264
387+143
9.9
12.4
11.9
16.0
11.8
10.9
13.8
13.2
16.5
16.9
17.1
13.9
13.7+2.4
12.3
15.1
16.2
20.6
16.0
14.5
16.8
16.4
20.4
23.4
21.7
17.4
17.6±3.3
163
155
254
87
97
209
215
85
79
80
79
241
218
35
227
"Less than" values not included.
for peat taken from Casagrande (1976) are included to illustrate concentra-
tions of certain elements in a modern coal-forming type of environment.
The only elements in coal that show concentrations significantly in
excess of crustal abundance (dark values) are S and Se (Gluskoter et al.,
1977). This is expected because the chemistry of these elements is very
similar. They occur at concentrations of 50 to 20 times the clarke value.
Most of the 'elements that are found in relatively high concentrations in
plants (Fe, Ca, K, Mg, Na, P) and certain of the other known nutrients such
as Mn, B, and Zn are less concentrated in the organic fraction of coal than
in plant material. Perhaps these elements are in soluble or mobile forms
that are readily leached from the material during epigenesis before polymeri-
zation takes place. Conceivably, some may also have been leached from the
coal by the acid extraction, as in the case of the exchangeable ions studied.
56
-------
TABLE 24. Mean MMF values for coal compared to plant material and crustal abundance (ppm)
Element
Si
Al
Fe
Ca
Na
Mg
K
Ti
P
Mn
S
Be
B
Sc
V
Cr
Co
Ni
Cu
Zn
Ga
As
Se
Br
Rb
Sr
Mo
Cd
Sb
Cs
Ba
La
Ce
Sm
Eu
Tb
Dy
Yb
Lu
Hf
Ta
W
Pb
Th
U
Mean MMF
59
63
60
39
3.1
16
3.9
34
3.1
1.0
12,200
0.05
10
0.7
4.8
5.9
1.2
3.4
2.5
0.7
0.6
0.15
0.4
4.4
0.25
5.9
0.3
0.1
0.3
0.06
6.5
1.4
1.3
0.3
0.08
0.09
0.6
0.18
0.05
0.17
0.04
0.18
0.2
0.5
0.2
Mean (plant)*
200-5,000
0.5-4,000
140
18,000
1,200
3,200
14,000
1
2,100
630
3,400
<.l
50
0.008
1.6
0.23
0.5
0.3
14
100
0.06
0.2
0.2
15 •
20
26
0.9
0.6
0.06
0.2
14
0.006
0.03
0.002
0.02
<0.02
0.01
0.07
2.7
0.04
NBSf
(orchard leaves)
480
400
290
20,900
78.
6,000
14,000
0.06
2,300
0.91
1,900
0.03
33
0.7
2.3
0.2
1.3
12
25
0.08
10
0.08
10
12
37
0.3
0.11
3.0
0.04
51
0.09
1
0.3
3.3
<2
45
65
0.03
CrustalJ
abundance
277,200
81,300
50,000
36,300
28,000
20,000
25,900
4,400
1,050
950
260
2.8
10
22
135
100
25
75
55
70
15
1.8
0.05
2.5
90
3.75
1.5
0.2
0.2
3
425
30
60
6.0
1.2
0.9
3.0
3.4
0.5
3
2
1.5
13
7.2
1.8
\
Peat*.*
339 (25-2,100)
5,396
3,580 (77-20,700)
965 (200-4,750)
6,525 (4-35,000)
121 (7-701)
*Siegel, 1974. Values on dry weight basis.
tVarious literature sources. Values on dry weight basis.
$Mason, 1958.
**Casagrande, 1976. Values on dry weight basis.
57
-------
From the coal washability and demineralization data it seems probable
that the largest portion of trace and minor elements are not associated with
the organic fraction of the coal.
IMPORTANCE OF MINERAL MATTER
Although many elements exhibit some organic association, the total
elemental content of acid-demineralized coals in tables 9 through 17 generally
is low, ranging only from 250 to 600 ppm (excluding organic sulfur). Addition
of exchangeable, soluble, and chelated elements still results in the con-
clusion that most of the trace and minor elements in coal are in a mineral
form and are subject to significant reduction by physical cleaning procedures.
Sulfides, sulfates, carbonates, quartz, and clay minerals, together with
small amounts of many other minerals, form a multi-component system in the
coal with complex origins and variable chemical compositions. The chemical
elements present in the mineral matter occur not only as major components
of minerals but also, to a limited extent, as isomorphic replacements in
solution or as exchangeable cations on clays. These types of sites in the
mineral matter are presumably the position of many of the trace elements
found in coals.
Table 25 gives the principal minerals commonly found in coals and some
of the trace elements associated with them. These associations have been
compiled from the results of trace element investigations of coal (Gluskoter
et al., 1977; O'Gorman and Walker, 1972; Miller and Given, 1978) and from
reviews of basic geochemical and mineral research (Deere et al., 1966; Weaver
and Pollard, 1973; and Grim, 1968).
Kaolinite, illite, and expandable clays commonly make up a major portion
of the mineral matter of most coals. Cation adsorption and exchange are
important properties of these minerals. The minor and trace alkali and
alkaline earth elements are favored for the exchangeable sites in clays.
Because of inherent higher cation-exchange capacities, illites, montmorillo-
nites, and mixed-layered clays tend to adsorb a greater variety of ions than
kaolinite. A number of elements are also known to substitute for Al, Si, and
other major constituents bound into the crystal lattice. Determinations
of trace elements in partings and shale strata associated with coal seams
indicate higher concentrations of many minor and trace elements in these com-
ponents, but because of the complex combinations of clays and other incor-
porated minerals, specific mineral-trace element associations are inconclusive.
COAL CLEANING APPLICATION
Knowledge of the distribution and form of elements within a coal will
allow better predictions of the cleaning potential for coal than are now
possible. Table 26 shows the wide differences in the organic association of
trace elements in coals; broadly speaking these differences may be classified
within each of the three major coal-producing areas.
For the Illinois coals used in this study, Br, Ge, Be, Sb, B, and organic
sulfur consistently fall in the organic phase. The sulfide-forming elements,
Zn, As, Cd, Fe, and pyritic sulfur, are consistently found in the most inor-
ganic fraction and can, therefore, usually be materially reduced by gravity
58
-------
TABLE 25. Elements commonly associated with the principal minerals found in coals*
Mineral' phases '
Major constituents
Trace constituents
Sulfides
Pyrite, marcasite
Sphalerite
Galena
Sulfa'tes
Barite
Gypsum
Carbonates
Calcite
Siderite
Ankerite
Dolomite
Phosphates
Apatite
Fe,
Zn,
Pb,
Ba,
Ca,
Ca
Fe
Ca,
Ca,
Ca,
S
S
S
S
S
Fe
Mg
P, F
( As,
Fe,
( Ni,
Sr,
'
(Ba,
Fe,
I
Cd, Hg, Ag, Pb,
Zn, Cjj. Co, Sn,
Mo/Se); Ga
\_-^
Pb, Ca
Sr, Pb, Mn, Ca
Mg
Rare earths, U, Ce, Mn, Cl, Mg
Silicates
Quartz
Zircon
Tourmaline
Plagioclase feldspar
Apall feldspar
Muscovite
Clay minerals
Kaolinite
Illite
Montmorillonite
Mixed layer clays
Chlorite
Si
Si, Zr
Ca, Mg, Fe, B, Al, Si
Ca, Na, Al, Si
K, Al, Si
K, Al, Si
Al, Si
Al, Si, K
Al, Si, Mg, Fe
Al, Si, K, Mg, Fe
Al, Si, Fe, Mn, Mg
Hf, Th, P
Li, F
Ba, Sr, Mn, Ti, Fe, Mg
Rb, Ba, Sr, Fe, Mg, Ti, Li
F, Rb, Cs, Ba, Mg, Fe
Ti, Mg, Fe, and others
'Fe, Mg, Ca, Na, K, Ti,
Li, V, B, Mn, Cr, Cu, Ni,
Rb, Cs, Ga, Be, Zn, Se, F,
La, Ba, Sr, Co, and others
*This partial listing does not preclude the probability of additional mineral-trace element
associations.
separation procedures. A number of other elements, Zr, Hg, Pb, Hf, and Mn,
also are highly inorganic in association and can be removed rather easily.
The other elements determined—Al, Si, Ti, Mo, K, P, Ga, Ca, Cr, Co, Ni, Cu,
Mg, Se—are either intermediate in their association or highly variable.
Br, Ge, Sr, and organic sulfur have some of the highest organic
affinities and As, Rb, K, and pyritic sulfur are among the highest inorganic
affinities in the eastern United States coals. Other elements that show
relatively high organic associations are B, Ba, Be, Br, and Co. The remaining
elements are variable or intermediate in their association.
The western coals contain a largerxnumber of elements with high organic
affinities (B, Mg, Br, Sr, Be, P, Na, and Ca) than coals studied from either
of the other regions. Elements such as Si, As, Cs, Hg, Pb, and pyritic
sulfur are highly inorganic; the other elements are variable in their associa-
tions.
In a physical cleaning process the elements that have high organic
affinities are difficult to remove; conversely the inorganic elements are
59
-------
TABLE 26. Organic association of trace elements in coal: Illinois coals
C18560
Float-sink set No. 1
C17001
Float-sink set No. 2
C18126
Herrin (No. 6)
Coal Member
Illinois
Davis
Coal Member
Illinois
Herrin (No. 6)
Coal Member
Illinois
Float-sink set No. 3
Ge 1.76
U
ORS
Hg
V
Br
Sb
Dy
Be .87
B, Cr .77
Ni
Co
Eu
Cu
Na
Lu
Sc
K
Th
Ag
Yb .52
Zr .49
Hf
TOS, Rb, Ti
Cs, Ta
Sm
Pb
Al
Si
Se
Mg .27
SUS . 17
Ge 1.28
ORS
B
Be
Ni
Na, Ti
P
Cr, Se
Sb
Ga .66
Co .65
Ca, K
V
Al
Cu .56
Si .50
Mg
Mn .35
Zr .23
Ge
ORS
B
Be
Sb
SUS
V
TOS
Mo
Na
Ga
Se
Cr
Ni
Co
Hg
Cu
P, Fe, Ti
1.29
.67
.62
.40
.39
.25
.16
Sn, HTA, LTA
Ba, Ga
Cd, Ce, Sr
Mn, Ca, Fe
PYS
As, La, Zn
P
.03
HTA
LTA
TOS
As, Hg
Mo, Pb, Fe
Cd, PYS
Zn, SUS
.02
Zr, K
LTA, PYS
Al, HTA
Si
As, Pb
Cd, Mn, Zn, Ca
.04
60
-------
TABLE 26. Continued. Eastern coals
C18841
Pittsburgh No. 8 Seam
West Virginia
Float-sink set No. 4
ORS 1.07
Sr
Br
B
U
Ba
P, TOS
Ge .69
Cd .66
Dy
Pb
Eu, Na
Be, Co, Ga .53
t
Ca .50
Mg
V
Cu
Hg
La
Ni, Sm
Mn
Zn
Ce, Sb
Cr, Sc
Se
Sn
Al
Tb
Yb
Zr^Fe, Hf .30
Lu .26
As, PYS
Ta
Th
Rb
LTA
SUS
HTA
K, Si
Cs
Ti .05
C19824
Pittsburgh No. 8 Seam
West Virginia
Float-sink set No. 5
ORS 1.15
B
Br
Sr
Ba
TOS
Co, Ga
Be
U, Yb
Sm
Na .71
Ce, La, P .68
Dy, Eu, I, Sc, W
Li
Lu, Ni, Th, Al
Cr, Ti
V
Se
Ta .51
Cu .49
Hg
Hf
. Si
Sb
Zn
Cs
Zr .27
Rb, PYS .18
Fe
HTA
LTA
SUS
As
K
Cd
Sn
Mn, TI
Mo, Pb, Ca, Mg .04
C18820
Pocohontas No. 4
West Virginia
Float-sink set No. 6
ORS 1.18
Co
Sn
Br
Ni
Sr
Be
W
Ba
Ge
Fe .67
P .65
Dy, Yb
Eu
V
Cu, Sb
Tb
Ca
Ag, Lu, Zn .52
Na .50
Ga
B
Se, Sm
La
Mn, U
Cr, Pb
.Mg
Th, Ti
Hg, Ta .28
Hf .24
Zr
Cs
Rb, K
Si
PYS
As .07
C18848
Blue Creek
Alabama
Float-sink set No
Br 1
Ge
Co
ORS, TOS
SUS
Hg
Ni 1
Sr
Cu, Dy
Be
V
La
Ag
U
W
Lu
Pb, Sn
Sm, Tb
Eu, Ga, Sb, Ce
PYS
Ba
Cr, P, Zr
Se
Yb
Ti
Sc
Cd
Hf, Fe
Th
Al
B
Ta, Ca
Zn
Na
LTA
HTA, Si
K
Cs, Rb
Mg
As, Mn f-
. 1
.20
.01
.80
1L
45
34
21
05
61
-------
TABLE 26. Continued. Western coals
C19854
Rosebud Seam
Montana
Float-sink set No. 8
B 1.24
W
ORS
P
Br
Sr
Mg
Sb
La
Ce, Eu
Na
Mo
Ca
Co
Tb
Sc
Dy
F, Ga
Ge, Yb
Be, Sm .73
Lu .68
Al
Ni
Ta
V
U
Th .56
Cu .44
Hf
Ag .33
Ti .15
Li
LTA
Tl
Cr ..
HTA
Cd, Si
Se
Mn, Pb, Sn, Zr
As, Cs, Hg, Rb
PYS, Ba, I, Zn, Fe, K, SUS, Tos .02
C19000
Black Mesa Field
Arizona
Float-sink set No. 9
Zn 2.2
B
Na
Cd
Mg, ORS
P
Ba
Fe
Ni, TOS
Sr
Br, Co
Dy, Ca
Ag
Be .79
Yb .75
V, Cu
Lu
Sb
Ce, Sc
Se
La
Eu .57'
Cr, Tb .54
Mn, K
W
U
Hf, Sm
Zr
Rb
Ta, Al
Ga, Th
Ti
Sn .29
HTA .22
Hg
LTA
PYS
As
Si
Pb
Cs, Ge .03
62
-------
more easily removed. Depending on the coal, the elements that are intermed-
iate or variable in their association will exhibit a limited potential for
reduction or a large variation in procedures for removal. The low-rank
western coals contained the largest number of elements not readily removed
by standard washing methods (table 26), in many cases, these elements have
rather low concentrations and would not be expected to present a problem.
The potential for reduction of elements and minerals in coal, however,
is dependent on characteristics other than just their organic-inorganic
associations. The particle size of the minerals plays a significant role
in the reduction potential. For example, 95 percent of the pyrite occurring
in coal C-19824 has an average particle size of only 8 microns, and 15
percent of the pyrite is encapsulated within the coal particles; this makes
its removal extremely difficult. (Kuhn et al., 1978). (For all practical
purposes, such particles are "organically associated.") Furthermore, if
an element such as Mn is associated with calcite, its removal is easier than
if associated only with clay minerals. Clays tend to concentrate in the
lighter fractions of the coal, and they are often finely dispersed within the
macerals. Compositional trends of the two coals selected for clay analysis
(table 21) show higher proportions of kaolinite in the lighter fractions and
increased amounts of illite and mixed-layer clays in the 1.60 S fractions.
Such variations have a practical importance for utilization. The com-
position of the clay and other minerals in coals affects the fusion tempera-
ture of the resulting ash. White and O'Brien (1964) have indicated that
increased concentrations of illite, especially in conjunction with higher
amounts of carbonate, will lower the melting point and viscosity and change
the glass-forming characteristics of the ash. (See also Kent and Champion,
1964) If a portion of the clays is removed during cleaning, the resultant
clay composition may substantially change; trace element contents and adsorp-
tion properties are altered as well as fusion and sintering characteristics
of the ash. •
These considerations and others, such as variability among and within
coal seams, will modify interpretations placed upon organic affinities or
associations. The organic affinity index when it is used in conjunction :
with these factors will be most useful in quantifying the potential for
coal cleaning.
63
-------
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67
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-80-003
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE ANDSUBTITLE
Abundance of Trace and Minor Elements in Organic
and Mineral Fractions of Coal
5. REPORT DATE
January 1980
6. PERFORMING ORGANIZATION CODE
.K.Kuhn, F.L.Fiene, R.A.Cahill,
H.J.Gluskoter, and N. F.Shimp
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Illinois State Geological Survey
University of Illinois
Urbana, Illinois 61801
10. PROGRAM ELEMENT NO.
EHE623A
11. CONTRACT/GRANT NO.
68-02-2130
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 11/75-5/79
14. SPONSORING AGENCY CODE
EPA/600/13
15. SUPPLEMENTARY NOTES jjERL-RTP project officer is N. Dean Smith, Mail Drop 61, 919/
541-2708.
16. ABSTRACT
The report gives results of subjecting 27 U.S. coals to float/sink, acid,
and ion-exchange treatments. From these treatments, coal fractions were obtained
and analyzed to determine the organic and mineral associations of 45 elements. Of
the elements studied, B, Be, Br, Ge, and Sb were consistently classified organic;
sulfide-forming elements (Zn, As, Cd, and Fe) were classified inorganic; and others
(e.g. , Al, Ca, Ga, Ni, P, Si, and Ti) were intermediate or variable in their asso-
ciation. Three general observations were made: (1) the total concentration of an ele-
ment in coal is not indicative of its concentration in the organic phase; (2) because
concentrations vary widely, an accurate appraisal of trace and minor element asso-
ciations requires that each coal be evaluated separately; and (3) the highest concen-
trations of trace and minor elements in coal occur in the mineral matter. Despite
evidence that many elements exhibit some degree of organic association, most of
the trace and minor elements in these coals were in a mineral form. Thus many
elements could be significantly reduced by physical cleaning. The degree of reduc-
tion depends on the mineral, its size, and its distribution.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATl Field/Group
Pollution
Coal
Analyzing
Organic Compounds
Minerals
Coal Preparation
Pollution Control
Stationary Sources
Characterization
Coal Cleaning
13B
08G
14B
07C
081
13. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
68
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
68
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