ASTM D2795-95
(Test Method)Standard Test Methods for Analysis of Coal and Coke Ash (Withdrawn 2001)
Standard Test Methods for Analysis of Coal and Coke Ash (Withdrawn 2001)
SCOPE
1.1 These test methods cover the rapid and inexpensive analysis of coal and coke ash for the commonly determined major elements.
1.2 The test methods appear in the following order: Sections Silicon Dioxide (SiO2) 10 to 12 Aluminum Oxide (Al2O3) 13 to 15 Ferric Oxide (Fe2O3) 16 to 18 Titanium Dioxide (TiO2) 19 to 22 Phosphorus Pentoxide (P2O5) 23 to 25 Calcium Oxide (CaO), and Magnesium Oxide (MgO) 26 to 29 Sodium Oxide (Na2O) and Potassium Oxide (K2O) 30 to 33
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety problems, 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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D2795–95
Standard Test Methods for
Analysis of Coal and Coke Ash
This standard is issued under the fixed designation D 2795; 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 (ϵ) indicates an editorial change since the last revision or reapproval.
1. Scope from As-Determined to Different Bases
D 5142 Test Methods for Proximate Analysis of the Analy-
1.1 These test methods cover the analysis of coal and coke
sis Sample of Coal and Coke by Instrumental Procedures
ash for the commonly determined major elements.
E 380 Practice for Use of the International System of Units
1.2 The test methods appear in the following order:
(SI) (the Modernized Metric System)
Sections
3. Summary of Test Methods
Silicon Dioxide (SiO ) 10to12
Aluminum Oxide (Al O ) 13to15
2 3
3.1 The coal or coke to be analyzed is ashed under standard
Ferric Oxide (Fe O ) 16to18
2 3
conditions and ignited to constant weight. Two solutions are
Titanium Dioxide (TiO ) 19to22
Phosphorus Pentoxide (P O ) 23to25
2 5 prepared from the ash. SolutionAis obtained by fusing the ash
Calcium Oxide (CaO), and Magnesium Oxide (MgO) 26 to 29
with sodium hydroxide (NaOH) followed by a final dissolution
Sodium Oxide (Na O) and Potassium Oxide (K O) 30 to 33
2 2
of the melt in dilute hydrochloric acid (HCl). Solution B is
NOTE 1—Test Methods D 1757D 1757 is used for determination of
prepared by decomposition of the ash with sulfuric (H SO ),
2 4
sulfur.
hydrofluoric (HF), and nitric (HNO ) acids. SolutionAis used
1.3 The values stated in SI units (Practice E 380E 380) shall
for the analysis of SiO and Al O , and Solution B for the
2 2 3
be regarded as the standard. The values given in parentheses
remaining elements.
are for information only.
3.2 The two solutions are analyzed by a combination of
1.4 This standard does not purport to address all of the
methods: (1) spectrophotometric procedures are used for SiO ,
safety concerns, if any, associated with its use. It is the
Al O,Fe O,TiO , and P O;(2) chelatometric titration for
2 3 2 3 2 2 5
responsibility of the user of this standard to establish appro-
CaO and MgO; and (3) flame photometry for Na O and K O.
2 2
priate safety and health practices and determine the applica-
See Fig. 1 for a general outline of the methods and procedures
bility of regulatory limitations prior to use.
used for each determination.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 Acompositional analysis of the ash is often useful in the
D 346 Practice for Collection and Preparation of Coke
total coal quality description. Knowledge of the ash composi-
Samples for Laboratory Analysis
tion is also useful in predicting the behavior of the ashes and
D 1193 Specification for Reagent Water
slags in combustion chambers. Utilization of the coal combus-
D 1757 Test Methods for Sulfur in Ash from Coal and
tion ash by-products sometimes depends on the chemical
Coke
composition of the ash.
D 2013 Test Method for Preparing Coal Samples forAnaly-
4.2 It should be noted that chemical composition of labora-
sis
tory prepared coal ash may not exactly represent the compo-
D 3173 Test Method for Moisture in theAnalysis Sample of
sition of mineral matter in the coal, or the composition of the
Coal and Coke
fly ash and slags resulting from the commercial scale burning
D 3174 TestMethodforAshintheAnalysisSampleofCoal
of the coal.
and Coke from Coal
5. Apparatus
D 3180 Practice for Calculating Coal and Coke Analyses
5.1 Balance, sensitive to 0.1 mg.
5.2 Crucibles—Nickel crucibles of 50-cm capacity shall be
used for NaOH fusion of the ash, and platinum crucibles of
These test methods are under the jurisdiction ofASTM Committee D-5 on Coal
30-cm capacity shall be used for decomposition of the ash
and Coke and are the direct responsibility of Subcommittee D05.29 on Major
Elements in Ash and Trace Elements of Coal.
with HF.
Current edition approved Sept. 10, 1995. Published April 1996. Originally
ϵ1
published as D 2795 – 69. Last previous edition D 2795 – 86 (1991) .
Annual Book of ASTM Standards, Vol 05.05.
3 4
Annual Book of ASTM Standards, Vol 11.01. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D2795–95
FIG. 1 Outline of Methods for Analysis of Coal Ash
5.3 Emission Flame Photometer. in.) in depth in a fireclay or porcelain roasting dish. Place in a
5.4 Muffle Furnace—Electrically heated muffle furnace cold muffle furnace and heat gradually so that the temperature
with good air circulation and capable of maintaining a tem- reaches 500°C in 1 h and 750°C in 2 h. Ignite to constant
perature of approximately 750°C. weight (6 0.001 g, Note 2), at 750°C. Allow the ash to cool,
5.5 Absorption Spectrophotometer, visible region 380 to transfer to an agate mortar, and grind to pass a 150-µm (No.
780 nm. 100) U.S.A. standard sieve. Reignite the ash at 750°C for 1 h,
5.6 Sieves, 150 and 250-µm (No. 100 and No. 60) U.S.A. cool rapidly, and immediately weigh portions for analysis. If
standard. samples are stored, reignite the ash before weighing or deter-
mine loss on ignition at 750°C on a separate sample weighed
6. Purity of Reagents and Materials
out at the same time as the analysis sample. Thoroughly mix
6.1 Purity of Reagents—Reagent grade chemicals shall be each sample before weighing.
used in all tests. Unless otherwise indicated, it is intended that
NOTE 2—Coke may be ignited to constant weight at a temperature not
all reagents shall conform to the specifications of the Commit-
exceeding 950°C if difficulty in ashing is encountered.
tee on Analytical Reagents of the American Chemical Society,
9. Preparation of Analysis Solutions (Sample, Standards,
where such specifications are available. Other grades may be
and Blank)
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
9.1 Reagents and Materials:
accuracy of the determination.
9.1.1 Hydrochloric Acid (1 + 1)—Mix 1 volume of concen-
6.2 Purity of Water—Unless otherwise indicated, references
trated hydrochloric acid (HCl, sp gr 1.19) with 1 volume of
to water shall be understood to mean Type II reagent water as
water.
defined in specification D 1193D 1193.
9.1.2 Hydrofluoric Acid (sp gr 1.15)—Concentrated hydro-
fluoric acid (HF).
7. Sample
9.1.3 NationalInstituteofStandardsandTechnology(NIST)
7.1 Prepare the analysis sample in accordance with Test
Sample No. 99a Soda Feldspar.
Method D 2013D 2013 or Practice D 346D 346 by pulverizing
9.1.4 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
the material to pass 250 µm (No. 60) sieve.
(HNO ).
7.2 Analyze separate test portions for moisture and ash
9.1.5 Sodium Hydroxide (NaOH) pellets.
contents in accordance with Test Methods D 3173, D 3174, or
9.1.6 Sulfuric Acid (1 + 1)—Mix carefully while stirring 1
D 5142D 3173D 3174D 5142 so that calculations to other
volume of concentrated sulfuric acid (H SO , sp gr 1.84) into
2 4
bases can be made.
1 volume of water.
9.2 Procedure:
8. Preparation of Coal Ash and Coke Ash
9.2.1 The methods described are for typical ash samples;
8.1 Procedure—Prepare 3 to5gofash from the analysis
however, different dilutions or aliquots than those specified
sample. Spread the coal or coke in a layer not over 6 mm ( ⁄4
may be preferable to attain suitable concentrations for proper
intensities for various constituents. Colors developed as speci-
fied are stable unless otherwise stated. Although the methods
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
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia National Institute of Standards and Technology Sample No. 99a, soda feldspar
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, contains 65.2 % SiO and 20.5 % Al O . This reagent is used for standardization
2 2 3
MD. purposes only.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D2795–95
are described for a single sample, a group of ten or more can solve 9.0 g of sodium metabisulfite (Na S O)in90mLof
2 2 5
be processed at the same time. Each numbered step should be water, and add this solution to the solution above and mix.
completed for the group of samples being analyzed before Store in a plastic bottle. Unless this solution is freshly
proceeding to the next step. prepared, check the reducing properties of the solution against
9.2.2 SolutionAforSiO andAl O Determination—Weigh a known standard.
2 2 3
0.0500 g of sample and transfer to a 50-mL nickel crucible.
10.3 Tartaric Acid Solution (10 % in water)—Store in a
Add 1.5 g of NaOH, cover the crucible, and heat in a gas flame
plastic bottle.
to melt the NaOH. Swirl gently to ensure that no particles of
sample float on the surface of the melt. Continue fusion for
11. Procedure
about 5 min at dull red heat; then remove the crucible from the
11.1 Pipet a 10-mL aliquot of blank solution and 10 mL of
flame and swirl the melt, while cooling, to coat the crucible
each standard solution and Sample Solution A into separate
wall.Add about 25 mLof water to the melt and let stand for at
100-mLvolumetric flasks. Dilute each solution to 50 or 60 mL
least 1 h or overnight if convenient. Pour the contents of the
with water and mix. Add 1.5 mL of ammonium molybdate
crucible into a 600-mLbeaker containing 400 mLof water and
solution with a measuring pipet, mix, and let stand 10 min.
20 mL of HCl (1 + 1). (Do not allow the nickel crucible to
Pipet 4 mLof tartaric acid solution followed immediately by 1
come in contact with the acid.) With a rubber policeman,
mL of reducing solution into the first flask, mixing during the
remove any residue from the crucible and wash it into a beaker.
additions. Dilute contents of this flask immediately to the
Clean a 1000-mLvolumetric flask with HCl (1 + 1), rinse with
100-mL mark and mix before proceeding to the next flask. Let
water, and then transfer the solution in the beaker to it. Dilute
each solution stand 1 h; then determine its absorbance at 650
with water to the 1000-mL mark and mix.
nm, using the blank solution as a reference, assumed to have
9.2.2.1 Standard Solution for SiO and Al O
2 2 3
zero absorbance.
Determination—Prepare duplicate standard solutions in the
same manner (see 9.2.2) using 0.0500-g portions of NIST
12. Calculation
Sample No. 99a, soda feldspar. Also prepare a blank solution
as in 9.2.2, but omit the soda feldspar. Store the standard and 12.1 Compute factors f and f for each standard solution as
1 2
blank solutions in plastic bottles. follows:
9.2.3 Solution B for Fe O,TiO,P O , CaO, MgO, Na O,
2 3 2 2 5 2 f 5 C /A and f 5 C /A (1)
1 s 1 2 s 2
and K O Determinations—Treat 0.400 6 0.0005 g of sample
where:
in a 30-mL platinum crucible with 3 cm of H SO (1 + 1) and
2 4
C = concentration of SiO in the standard
10 mL of HF. Evaporate on an air bath until most of the HF is s 2
sample, %, and
removed then add 1 mL of HNO , and continue heating until
A and A = absorbances for replicate standard solution
strong fumes of sulfur trioxide (SO ) evolve. Cool the crucible 1 2
each containing 50 mg of standard sample.
and contents, add water to dissolve the residue, and digest on
12.2 Calculate the percent of silica in the ash as follows:
an air bath for ⁄2 h. Transfer the contents of the crucible to a
250-mLvolumetric flask. Cool to room temperature then dilute
SiO,% 5 FA (2)
to the 250-mL mark and mix (Note 3). Also prepare a blank
where:
Solution B (8.2.3), omitting the sample. Because of the
F =(f + f )/2, and
1 2
possibility of alkali contamination from the glass from which
A = absorbanceofthesamplesolutioncontaining50mgof
the flask is made, determine sodium and potassium the same
ash.
day that Solution B is prepared, or withdraw 25 mL with a
pipet and store in a plastic bottle.
ALUMINUM OXIDE (Al O )
2 3
NOTE 3—Althoughsomecalciumsulfate(CaSO )fromsampleshighin
calcium may not dissolve during digestion in the crucible, it normally will
13. Reagents
dissolve on further dilution. A small quantity of insoluble barium sulfate
(BaSO ) may still remain with some samples. This will settle to the
13.1 Acetic Acid, Glacial (CH COOH).
bottom of the flask and not interfere in determining the main constituents.
13.2 Alizarin Red-S Solution (0.1 % in water).
If appreciable insoluble residue is present, the solution can be filtered into
13.3 Calcium Chloride Solution (CaCl ) (7 g/500 mL)—
another 250-mL flask before finally diluting to the mark. 2
Transfer7gof calcium carbonate (CaCO ) to a 250-mL
beaker. Add about 50 mL of water and HCl (1 + 1) in drops
SILICON DIOXIDE (SiO )
until the CaCO is dissolved. Boil the solution for 1 to 2 min,
cool, and dilute with water to 500 mL.
10. Reagents
13.4 Buffer Solution—Dissolve 70 g of sodium acetate
10.1 Ammonium Molybdate Solution (7.5 g/100 mL)— Dis-
(CH COONa·3H O) in water, add 30 mL of CH COOH, and
solve 7.5 g of ammonium molybdate ((NH ) Mo O ·4H O) 3 2 3
4 6 7 24 2
dilute to 500 mL.
in 75 mLof water.Add 10 mLH SO (1 + 1) and dilute to 100
2 4
13.5 Hydroxylamine Hydrochloride Solution (10 % in
mL. Store in a plastic bottle.
water)—Prepare fresh.
10.2 Reducing Solution—Dissolve 0.7 g of sodium sulfite
(Na SO ·7H O) in 10 cm of water. Add 0.15 g of 1- 13.6 ThioglycollicAcid (5 %)—Dilute 5 mLof thioglycollic
2 3 2
amino-2-naphthol-4-sulfonic acid and stir until dissolved. Dis- acid to 100 mL with water. Prepare fresh.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D2795–95
14. Procedure allow to stand for 10 min. Then add 10 mL of orthophenan-
throline solution with a graduated cylinder to each flask and
14.1 Pipet a 10-mL aliquot of Sample SolutionA, 20 mL of
mix. Finally, add 10 mL of sodium citrate solution with a
each Standard Solution A, and 20 mL of blank solution into
graduated cylinder to each flask, dilute to 100
...
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