ASTM C816-85(2005)
(Test Method)Standard Test Method for Sulfur in Graphite by Combustion-Iodometric Titration Method
Standard Test Method for Sulfur in Graphite by Combustion-Iodometric Titration Method
SIGNIFICANCE AND USE
Sulfur, even in very low concentrations, is of concern in a nuclear reactor because of potential corrosion of metallic components. This test method has the sensitivity to analyze very low sulfur contents in graphite using very small samples.
This test method can be used to characterize graphite for design purposes.
SCOPE
1.1 This test method covers the determination of sulfur in graphite in the concentration range from 1 to 200 g/g in a 1-g sample or 5 to 1000 g/g in a 0.2-g sample.
1.2 The values stated in SI units are to 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.
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Standards Content (Sample)
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An American National Standard
Designation:C816–85 (Reapproved 2005)
Standard Test Method for
Sulfur in Graphite by Combustion-Iodometric Titration
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Method
This standard is issued under the fixed designation C816; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope components. This test method has the sensitivity to analyze
very low sulfur contents in graphite using very small samples.
1.1 This test method covers the determination of sulfur in
4.2 Thistestmethodcanbeusedtocharacterizegraphitefor
graphite in the concentration range from 1 to 200 µg/g in a 1-g
design purposes.
sample or 5 to 1000 µg/g in a 0.2-g sample.
1.2 The values stated in SI units are to be regarded as the
5. Interferences
standard.
5.1 Any substance that releases volatile material, which
1.3 This standard does not purport to address all of the
tends to enhance or to bleach the starch-iodine complex, will
safety concerns, if any, associated with its use. It is the
interfere. Halogens and oxides of nitrogen interfere through
responsibility of the user of this standard to establish appro-
darkening the color of the starch-iodine complex. Ultraviolet
priate safety and health practices and determine the applica-
light will also darken the solution. A tube packed with either
bility of regulatory limitations prior to use.
silver wool or antimony filings placed in the line between the
2. Referenced Documents furnace and titration assembly will remove halogens from the
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gas stream.
2.1 ASTM Standards:
5.2 If the solution in the titration vessel becomes colorless
D3177 Test Methods for Total Sulfur in the Analysis
during the titration, some SO will be lost and a low result will
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Sample of Coal and Coke
be obtained for the sulfur content.
E50 Practices for Apparatus, Reagents, and Safety Consid-
erations for Chemical Analysis of Metals, Ores, and
6. Apparatus
Related Materials
6.1 Apparatus for the determination of sulfur by direct
3. Summary of Test Method combustion shall be in accordance with No. 13 in Fig. 13 of
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Practices E50.
3.1 The sample is burned in oxygen and a major portion of
the sulfur is converted to sulfur dioxide. The sulfur dioxide is
7. Reagents and Materials
passed through a potassium iodide-starch solution where it is
7.1 Potassium Iodate Solution (0.0444 g/L)—Dissolve
titrated with potassium iodate solution. The potassium iodate
0.0444 g of potassium iodate (KIO ) in water and dilute to 1 L.
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solution is standardized against samples of known sulfur
content.
NOTE 1—The sulfur equivalent for the KIO solution is based on the
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following reactions:
4. Significance and Use
KIO 1 5KI 1 6HCl 5 3I 1 6KCl 1 3H O
3 2 2
4.1 Sulfur, even in very low concentrations, is of concern in
SO 1 I 1 2H O 5 H SO 1 2HI
2 2 2 2 4
a nuclear reactor because of potential corrosion of metallic
On the basis of 100 % conversion of sulfur to SO , 1 mL of this solution
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is equivalent to 20 µg of sulfur.
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This test method is under the jurisdiction of ASTM Committee D02 on
7.2 Hydrochloric Acid—Dilute 15 mL of concentrated hy-
PetroleumProductsandLubricants andisthedirectresponsibilityofSubcommittee
D02.F0 on Manufactured Carbon and Graphite Products.
drochloric acid (HCl, sp gr 1.19) to 1 L with water.
Current edition approved May 1, 2005. Published May 2005. Originally
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approved in 1977. Last previous edition approved in 1998 as C816 – 85 (1998) .
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DOI: 10.1520/C0816-85R05. The sole source of supply of the apparatus known to the committee at this time
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C816–85 (2005)
7.3 Starch-Potassium Iodide Solution—Add2gof arrow- 8.12 Make a blank run on an empty prefired boat, igniting
root starch to 50 mLof water. Separately boil 150 mLof water for the same length of time as the sample.
and slowly add the starch solution, stirring constantly. Cool, 8.13 Run st
...
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