Standard Test Method for Major and Minor Elements in Combustion Residues from Coal Utilization Processes

SIGNIFICANCE AND USE
A compositional analysis of the ash in coal is often useful in the total description of the quality of the coal. Knowledge of ash composition is also useful in predicting the behavior of ashes and slags in combustion chambers. Utilization of the ash by-products of coal combustion sometimes depends on the chemical composition of the ash.
Note that the chemical composition of laboratory-prepared coal ash may not exactly represent the composition of mineral matter in the coal or the composition of fly ash and slag resulting from commercial-scale burning of the coal.
SCOPE
1.1 This test method covers the analysis of the commonly determined major and minor elements in combustion residues from coal utilization processes.Note 1
Test Methods D 1757 or D 5016 shall be used for determination of sulfur.
1.2 The values stated in SI units (IEEE/ASTM SI 10 ) shall to be regarded as the standard.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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Historical
Publication Date
31-Mar-2006
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ASTM D3682-01(2006) - Standard Test Method for Major and Minor Elements in Combustion Residues from Coal Utilization Processes
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D3682 − 01(Reapproved 2006)
Standard Test Method for
Major and Minor Elements in Combustion Residues from
Coal Utilization Processes
This standard is issued under the fixed designation D3682; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Sample of Coal and Coke by Instrumental Procedures
(Withdrawn 2010)
1.1 This test method covers the analysis of the commonly
E691 Practice for Conducting an Interlaboratory Study to
determined major and minor elements in combustion residues
Determine the Precision of a Test Method
from coal utilization processes.
IEEE/ASTM SI 10 Standard for Use of the International
NOTE 1—Test Methods D1757 or D5016 shall be used for determina-
System of Units (SI): The Modern Metric System
tion of sulfur.
1.2 The values stated in SI units ( IEEE/ASTM SI 10 ) shall
3. Summary of Test Method
to be regarded as the standard.
3.1 The combustion residue to be analyzed is ignited in air
1.3 This standard does not purport to address all of the
at 750°C to a constant weight. The ash is fused within lithium
safety concerns, if any, associated with its use. It is the
tetraborate (Li B O ) followed by a final dissolution of the
2 4 7
responsibility of the user of this standard to establish appro-
melt in either dilute hydrochloric acid (HCl) or dilute nitric
priate safety and health practices and determine the applica-
acid (HNO ). The solution is analyzed by atomic absorption/
bility of regulatory limitations prior to use.
emission for applicable elements.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 A compositional analysis of the ash in coal is often
D1193 Specification for Reagent Water
useful in the total description of the quality of the coal.
D1757 Test Method for Sulfate Sulfur inAsh from Coal and
3 Knowledge of ash composition is also useful in predicting the
Coke (Withdrawn 2009)
behavior of ashes and slags in combustion chambers. Utiliza-
D2013 Practice for Preparing Coal Samples for Analysis
tion of the ash by-products of coal combustion sometimes
D3173 Test Method for Moisture in the Analysis Sample of
depends on the chemical composition of the ash.
Coal and Coke
D3174 Test Method for Ash in the Analysis Sample of Coal
4.2 Note that the chemical composition of laboratory-
and Coke from Coal
prepared coal ash may not exactly represent the composition of
D3180 Practice for Calculating Coal and Coke Analyses
mineralmatterinthecoalorthecompositionofflyashandslag
from As-Determined to Different Bases
resulting from commercial-scale burning of the coal.
D5016 Test Method for Total Sulfur in Coal and Coke
Combustion Residues Using a High-Temperature Tube
5. Apparatus
Furnace Combustion Method with Infrared Absorption
5.1 Ashing Furnace, with an adequate air circulation and
D5142 Test Methods for ProximateAnalysis of theAnalysis
capable of having its temperature regulated between 700 and
750°C.
This test method is under the jurisdiction of ASTM Committee D05 on Coal
5.2 Fusion Furnace, with an operating temperature of
and Coke and is the direct responsibility of Subcommittee D05.29 on Major
1000°C.
Elements in Ash and Trace Elements of Coal.
Current edition approved April 1, 2006. Published April 2006. Originally
5.3 Platinum Dish, 35- to 85-mL capacity.
ε1
approved in 1978. Last previous edition approved in 2001 as D3682 – 01 . DOI:
10.1520/D3682-01R06.
5.4 Stirring Hotplate and Bars, operating temperature of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
200°C.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
5.5 Atomic Absorption Spectrometer—Any dual-channel in-
the ASTM website.
strument using a deuterium (D ) arc background corrector or
The last approved version of this historical standard is referenced on 2
www.astm.org. other comparable simultaneous background correction system.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3682 − 01 (2006)
6. Reagents weighted out at the same time as the analysis sample and make
the necessary corrections. Thoroughly mix each sample before
6.1 Purity of Reagents—Reagent grade chemicals shall be
weighing.
used in all tests. It is intended that all reagents shall conform to
the specifications of the Committee on Analytical Reagents of 7.2 If the ash is to be prepared from a coal, prepare the coal
the American Chemical Society, where such specifications are analysis sample in accordance with Practice D2013 by pulver-
available. Other grades may be used, provided it is first izing the materials to pass a 250-µm (No. 60) sieve.
ascertained that the reagent is of sufficiently high purity to
7.2.1 Analyze separate test portions of the coal for moisture
permit its use without lessening the accuracy of the determi- and ash contents in accordance with Test Methods D3173,
nation. The lithium tetraborate and lanthanum chloride re-
D3174,or D5142 so that calculations to other bases can be
agents in particular should be examined for alkali and alkaline made.
earth contamination.
7.2.2 Prepare the ash from a thoroughly mixed analysis
sample of coal. Spread the coal in a layer not over 6 mm ( ⁄4
6.2 Purity of Water—Unless otherwise indicated, references
in.) in depth in a fireclay or porcelain roasting dish. Place the
to water shall be understood to mean Type II reagent water as
dish in a cold muffle furnace and heat gradually so that the
defined in Specification D1193.
temperature reaches 500°C in 1 h and 750°C in 2 h. Ignite at
6.3 Aluminum Stock Solution (1000-ppm aluminum).
750°C until all carbonaceous matter is removed. Proceed with
6.4 Calcium Stock Solution (1000-ppm calcium).
the preparation of the ash in accordance with 7.1. If samples
are stored and the absorption of moisture or CO , or both, is in
6.5 Iron Stock Solution (1000-ppm iron).
question, reignite the ash using the 500-750°C staged combus-
6.6 Lanthanum Chloride Solution (175-g/Llanthanum chlo-
tion before use.Alternatively, determine loss on ignition using
ride (LaCl ) or equivalent 10 % lanthanum).
the 500-750°C staged combustion on a separate sample
6.7 Lithium Tetraborate—(Li B O ), powder. weighed out at the same time as the test portion and make the
2 4 7
necessary corrections. Thoroughly mix each sample before
6.8 Magnesium Stock Solution (1000-ppm magnesium).
weighing.
6.9 Potassium Stock Solution (1000-ppm potassium).
8. Procedure
6.10 Silicon Stock Solution (200-ppm silicon) (Note 2).
6.11 Sodium Stock Solution (1000-ppm sodium). 8.1 The solutions and proportions described below are for
typical ash samples as represented by American coals of
6.12 Solvent Acid—Dilute 50 mL of concentrated hydro-
bituminous rank. Therefore, stronger or weaker dilutions may
chloric acid (sp gr 1.19) or 50 mL of concentrated nitric acid
be required to establish suitable concentrations for those
(sp gr 1.42) to 1000 mL. Either acid solution may be used, but
elements of varying percents outside the range of the typical
whichever is chosen should be used throughout the subsequent
sample. Each analyst must determine the sensitivity and linear
solution preparations.
range of calibration of their equipment and choose concentra-
6.13 Titanium Stock Solution (1000-ppm titanium).
tion ranges for standards compatible with the samples and
instrument specific to their own work.
NOTE 2—Commercial silicon standards prepared from sodium silicate
have not proved satisfactory.Astandard stock solution can be prepared by
8.1.1 Calculations used in subsequent sections are devel-
fusing 0.1070 g of reignited spectrographic grade silica (SiO )with1gof
oped from the following general formula for percent concen-
lithium tetraborate, dissolving in solvent acid, and diluting to 250 mL as
tration of element oxide, E, in moisture-free coal ash:
described for sample preparation in 8.3.1 and 8.3.2. This solution is
200-ppm silicon. Preferable standard preparations for silica are made by
E 5 @~C 2 B!/~A 2 B!# 3 ~N/M! 3 F 3100 (1)
fusion and dilution of ash sample(s) of known composition in accordance
where:
with 8.3.1 and 8.3.2.The standard sample(s) should have a composition(s)
similar to the unknown.
A = absorbance of standard;
B = absorbance of blank;
7. Sample Preparation
C = absorbance of sample solution;
N = element in standard, ppm;
7.1 The combustion residue to be analyzed must first be
M = sample of solution, ppm; and
ignited in air at 750°C to a constant weight before analysis.
F = conversion from element to oxide.
Allow the ash to cool, transfer to an agate mortar, and grind to
NOTE 3—Concentrations in the ash may be converted to the air-dried
pass a 74-µm (No. 200) sieve. Reignite the ash at 750°C for 1
coal basis using the following expression:
h, cool rapidly, and immediately weigh portions for analysis. If
C 5 ~AB/100!
samples are stored, reignite the ash before weighing or deter-
mine the loss on ignition at 750°C on a separate sample
where:
C = oxide in air-dried coal, %;
A = oxide in ash, %; and
B = ash as determined in Test Method D3174 or Test Method D5142,
Reagent Chemicals, American Chemical Society Specifications, American
%.
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
See Practice D3180 for procedures to convert values to other bases.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
8.2 To minimize the potential of contamination, the plati-
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. numware must be prepared by boiling in solvent acid and
D3682 − 01 (2006)
rinsing thoroughly with reagent-grade water. After this initial 9.2). Only those standards need be prepared that bracket the
cleaning, the platinumware must be handled with clean tongs expected SiO concentrations in the samples.
and protected from further contamination from table tops, and
so forth. All glassware used in analyses must be equally clean
and equally protected.
8.3 Sample Fusion and Solution:
8.3.1 Weigh 0.1 6 0.0002 g of the sample as prepared in
7.2.2 into a platinum dish (5.3)(Note 4) and add 0.5 g of
Li B O . Mix the ash and lithium tetraborate well, then add an
2 4 7
additional0.5gofLi B O tocoverthemixture.Placethedish
2 4 7
in a clean silica or refractory tray and place in a muffle furnace
preheated to 1000°C; 15 min at 1000°C is sufficient to fuse the
mixture completely. Remove the tray and dish and cool to
room temperature. Carefully rinse the bottom and outside of
the platinum dish to remove possible contamination, then place
it in a clean 250- or 400-mL beaker. Place a clean TFE-
fluorocarbon-coated stirring magnet inside the dish, add 150
mL of solvent acid to the beaker and dish, and place immedi-
ately on the stirring hotplate. Heat the solution to just below
boiling temperature and maintain for not more than 30 min
with constant stirring. This time and temperature are sufficient
to completely dissolve the melt. If stirring is not maintained
constantly, some of the ash constituents are apt to precipitate
and the analysis must be repeated.
NOTE 4—The use of graphite crucibles and subsequent dissolution of
fused beads from them was not investigated; however, their successful use
in similar methods has been reported.
8.3.2 Remove the beaker from the hotplate and permit to
cool to room temperature. Quantitatively transfer the solution
to a 200-mL volumetric flask, wash the platinum dish and
beaker with small amounts of solvent acid and dilute to the
200-mL mark with the solvent acid. This solution is 500 ppm
with respect to the total sample and contains 5 g/L of Li B O
2 4 7
solution.
8.3.3 Solution 1—Pipet 20 mL of the sample solution
prepared in 8.3.2 into a 50-mL volumetric flask and dilute to
volume with solvent acid. This solution is 200 ppm with
respect to the total sample and contains 2 g/L of Li B O
2 4 7
solution.
8.3.4 Solution 2—Pipet 10 mL of the sample solution
prepared in 8.3.2 into a 100-mLvolumetric flask, add 10 mLof
lanthanum solution (see 6.6), and dilute to volume with solvent
acid. This solution is 50 ppm with respect to the total sample
and contains 0.5 g/L of Li B O solution.
2 4 7
NOTE 5—Lanthanum was included in the solution as a release agent in
those determinations that may require it (for example, calcium). Alterna-
tive measures, such as the use of nitrous oxide flame, are permissible.
9. Silicon Dioxide (SiO )
9.1 Preparation of Standards—Prepare a series of standards
by combining the following volumes of the silicon stock
solution (see 6.10) with 1 mL of the aluminum stock solution
(see 6.3) and diluting to 100 mL with the blank solution (see
Muter, R. B. and Nice, L. L., “Major and Minor Constituents in Siliceous
Materials byAtomicAbsorption Spectroscopy,”Advances in Chemistry Series 141,
Trace Elements in Fuels, American Chemical Society, Washington, DC, 1975, pp.
57–65.
D3682 − 01 (2006)
11.4 Atomic Absorption Operating Conditions—Use an iron
Silicon, Stock
Solution (6.12), mL Silicon, ppm Equivalent SiO,%
hollow-cathode lamp and set the monochromator at 248.3 nm.
Use an air-acetylene flame of stoichiometric composition.
25 50 53.5
20 40 42.8 Adjust other instrument parameters to optimum for the particu-
15 30 32.1
lar equipment used.
10 20 21.4
11.5 Determination—Read the absorbance values for the
9.2 Blank Solution—Prepare a solution of 2 g/L of Li B O
2 4 7
blank solution, the standard solutions, and the sample solution.
solution in solvent acid.
Determine percent Fe O as follows:
2 3
9.3 Sample Solution—Use the 200-ppm sample solution as
Fe O ,% 5 @~C 2 B!/~A 2 B!# 3 N 32.86 (4)
2 3
prepared in 8.3.3.
where:
9.4 Atomic Absorption Operating Conditions—Use a silicon
A = absorbance of standard nearest C,
hollow-cathode lamp and set the monochromator at 251.6 nm.
B = absorbance of blank,
Use a nitrous oxide/acetylene flame. Adjust other instrument
C = absorbance of sample, and
parameters to optimum for the particular equipment used.
N = iron in standard, ppm.
9.5 Determination—Read out absorbance values for the
12. Calcium Oxide (CaO)
blank solution, standard solutions, and sample solution. In this
and all subsequent determinations, those instruments so
12.1 Preparation of Standards—Prepa
...

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