ASTM D1757-96(2002)

Standard Test Method for Sulfur in Ash from Coal and Coke

SCOPE
1.1 This test method pertains to the determination of sulfate sulfur in coal or coke ash.
1.2 The values stated in SI units (Practice E 380) shall be regarded as the standard.
1.3 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.

General Information

• Status: Historical
• Publication Date: 09-Apr-2002
• ICS: 73.040 - Coals
• Technical Committee: D05 - Coal and Coke
• Drafting Committee: D05.29 - Major Elements in Ash and Trace Elements of Coal

Relations

• Replaces: ASTM D1757-96 - Standard Test Method for Sulfur in Ash from Coal and Coke
• Effective Date: 10-Apr-2002
• Replaced By: ASTM D1757-03 - Standard Test Method for Sulfate Sulfur in Ash from Coal and Coke (Withdrawn 2009)
• Effective Date: 10-Apr-2003
• Referred By: ASTM D3174-12(2018)e1 - Standard Test Method for Ash in the Analysis Sample of Coal and Coke from Coal
• Effective Date: 10-Apr-2002

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 1757 – 96 (Reapproved 2002)
Standard Test Method for
Sulfate Sulfur in Ash from Coal and Coke
This standard is issued under the fixed designation D 1757; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope may be present to the sulfate form. After neutralization and
precipitation of iron with ammonium hydroxide, the mixture is
1.1 This test method pertains to the determination of sulfate
filtered and sulfate in the filtrate is determined gravimetrically
sulfur in coal or coke ash.
as barium sulfate (BaSO ).
1.2 The values stated in SI units (Practice E 380) shall be
3.2 Test Method B—Eschka Mixture—A specified quantity
regarded as the standard.
of ash and Eschka mixture are ignited together in air. The
1.3 This standard does not purport to address all of the
sulfates are dissolved in hot water and separated from undis-
safety concerns, if any, associated with its use. It is the
solved ash residue and magnesium oxide by filtration. Sulfate
responsibility of the user of this standard to establish appro-
in the filtrate is determined gravimetrically as barium sulfate
priate safety and health practices and determine the applica-
(BaSO ).
bility of regulatory limitations prior to use.
4. Significance and Use
2. Referenced Documents
4.1 Laboratory furnace temperature and furnace ventilation
2.1 ASTM Standards:
2 have an influence on SO retention in laboratory ash. Conse-
D 1193 Specification for Reagent Water 3
quently, sulfur in ash as determined in the laboratory cannot be
D 2795 Test Methods for Analysis of Coal and Coke Ash
assumed to be equivalent to sulfur present in the mineral matter
D 3174 Test Method for Ash in the Analysis Sample of Coal
in coal or to the retention of sulfur in ash produced under the
and Coke from Coal
conditions of commercial utilization.
D 3177 Test Methods for Total Sulfur in the Analysis
4.2 The sulfate sulfur determined by these test methods can
Sample of Coal and Coke
be used to calculate the sulfur trioxide portion of ash so that the
D 3682 Test Method for Major and Minor Elements in
ash content or ash composition can be reported on a sulfur
Combustion Residues from Coal Utilization Processes
trioxide free basis.
D 4326 Test Method for Major and Minor Elements in Coal
and Coke Ash by X-Ray Fluorescence
5. Interferences
E 380 Practice for Use of the International System of Units
4 5.1 Barium in coal ashes can result in incomplete recovery
(SI) (the Modernized Metric System)
of sulfate sulfur.
2.2 British Standard:
5 5.2 High iron content can be encountered in coal and coke
BS 1016, Part 14 Analysis of Coal Ash and Coke Ash
ash and can introduce error if, during the sulfate precipitation,
3. Summary of Test Methods the iron is either partially adsorbed by the BaSO precipitate or
coprecipitated as iron sulfate.
3.1 Test Method A—Modified British Method—A specified
quantity of ash is digested in boiling dilute hydrochloric acid
6. Apparatus
solution to which bromine water is added to convert sulfite that
6.1 Muffle Furnace, electric, capable of maintaining a tem-
perature of 800 6 25°C for igniting barium sulfate.
This test method is under the jurisdiction of ASTM Committee D05 on Coal
6.2 Crucibles or Capsules, porcelain, platinum, alundum, or
and Coke and is the direct responsibility of Subcommittee D05.29 on Major
silica of 10 to 15-mL capacity, for igniting BaSO .
Elements in Ash and Trace Elements of Coal.
Current edition approved April 10, 1996. Published June 1996. Originally
7. Purity of Reagents
published as D 1757 – 60 T. Last previous edition D 1757 – 96.
Annual Book of ASTM Standards, Vol 11.01.
7.1 Purity of Reagents—Reagent grade chemicals shall be
Annual Book of ASTM Standards, Vol 05.06.
used in all tests. Unless otherwise indicated, it is intended that
Annual Book of ASTM Standards, Vol 14.04.
all reagents shall conform to the specifications of the Commit-
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. tee on Analytical Reagents of the American Chemical Society,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 1757
where such specifications are available. slowly adding concentrated NH OH (sp gr 0.90) until a slight
7.2 Purity of Water—Unless otherwise indicated, references excess is present as noted by the change in the methyl orange
to water shall be understood to mean reagent water as defined indicator, then add 5 mL excess (Note 1) constantly stirring to
by Type IV of Specification D 1193. coagulate the yellowish-brown ferric hydroxide precipitate.
Heat to just below boiling, hold for 15 min, and allow to settle
8. Analysis Sample
and stand for an additional 15 min. Filter the solution through
8.1 The analysis sample shall be prepared in accordance an ashless, close textured, double-acid-washed paper into a
400-mL beaker, washing the paper with four 20-mL portions of
with the section on Preparation of Coal Ash and Coke Ash in
one of the following Test Methods: D 2795, D 3174, D 3682, NH Cl—NH OH solution. Discard the filter.
4 4
or D 4326.
NOTE 1—The excess of strong ammonium hydroxide minimizes the
8.2 Prior to analysis re-ignite at the original conditions a
possibility of sulfate being carried down with the iron hydroxide precipi-
sufficient quantity of thoroughly mixed analysis sample for a
tate.
period of not less than 1 h.
10.3 Precipitation of Sulfate Sulfur:
8.3 For purposes of comparison of results between labora-
10.3.1 Add a few drops of methyl orange to the filtrate from
tories the analysis sample shall be taken from a common
10.2. Make it just neutral with dilute HCl (1 + 9), then add 10
analysis sample prepared according to the conditions specified
mL in excess. Boil the solution and slowly add 9 mL of BaCl
in 8.1 and 8.2.
solution from a pipet, while stirring constantly. Continue
boiling for 15 min and allow to stand 2 h, or preferably
ALTERNATIVE PROCEDURES
overnight, at a temperature just below boiling. Add 1 mL
TEST METHOD A—MODIFIED BRITISH STANDARD
BaCl . If additional precipitate forms repeat the digestion and
precipitation steps using half the weight of sample.
9. Reagents
10.3.2 Filter through an ashless, close-textured, acid-
9.1 Ammonium Chloride-Ammonium Hydroxide Solution—
washed paper and wash with hot water until 1 drop of AgNO
Dissolve 20.1 g of ammonium chloride (NH Cl) in approxi-
solution produces no more than a slight opalescence when
mately 500 mL of water, add 10 mL of concentrated ammo-
added to 8 to 10 mL of filtrate. Three to five washings are
nium hydroxide (NH OH, sp gr 0.90), dilute to 1 L with water,
usually adequate.
and mix thoroughly.
10.3.3 For samples calculating to less than 2 % SO (see
9.2 Ammonium Hydroxide, Concentrated (NH OH, sp gr
Section 13) the test should be repeated with the addition of
0.90).
25.0 mL of potassium sulfate solution (2 g/L) to the filtrate
9.3 Barium Chloride Dihydrate Solution (100 g/L)—
from 10.2. This “standard addition” method minimizes solu-
Dissolve 100 g of barium chloride (BaCl 2H O) and dilute to
2 2
bility losses of BaSO for tests on samples containing low
1 L with water.
quantities of SO .
9.4 Bromine Water, Saturated—Add an excess of bromine
10.4 Ignition of Barium Sulfate—Place the wet filter con-
to 1 L of wat
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