ASTM D5263-15

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Designation: D5263 − 93 (Reapproved 2008) D5263 − 15
Standard Test Method for
Determining the Relative Degree of Oxidation in Bituminous
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Coal by Alkali Extraction
This standard is issued under the fixed designation D5263; 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.
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ε NOTE—Eq 1 was editorially corrected in November 2010.
1. Scope
1.1 This colorimetric test method describes the determination of the relative degree of oxidation by alkali extraction of coals
that are high volatile A bituminous to low volatile bituminous in rank.
1.2 This test cannot be sensitive to thermally oxidized coal. It is intended for coals that may be oxidized as a result of
weathering.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
1.4 The values stated in SI units shall be regarded as standard.
2. Referenced Documents
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2.1 ASTM Standards:
D1193 Specification for Reagent Water
D4621D7448 Guide for Quality Management in an Organization That Samples or Tests Practice for Establishing the
Competence of Laboratories Using ASTM Procedures in the Sampling and Analysis of Coal and Coke (Withdrawn 2010)
3. Terminology
3.1 There are no terms in this standard that require new or other than dictionary definitions.
4. Summary of Test Method
4.1 Humic acids, which are present in oxidized coals, are extracted from the coal with sodium hydroxide solution. The degree
of oxidation is determined by colorimetrically measuring the transmittance of the alkali extract solution at 520 nm. The intensity
of the color produced by the humic acids is a function of the degree of oxidation.
5. Significance and Use
5.1 This test method is a relative measure of the degree of oxidation present in coal. It does not determine the quantitative
amount of oxidized coal present. It is only intended to serve as a guide to the supplier, buyer, and user for selecting coals for
metallurgical use.
NOTE 1—Lower rank bituminous coals are more easily extracted than higher rank coal.
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NOTE 1—The values shown in Table 1 are based on the transmittance obtained using the original procedure (wavelength at 520 nm, 17-mm light path,
2– to 3-min boiling time, dilution of the extract to 80 mL). At these conditions, coals that had transmittance values greater than 90 % were considered
to be unoxidized, coals less than 80 % were considered to be oxidized, and coals between 80 and 90 % were considered suspect. As this procedure
becomes accepted as the standard and more experimental data are gathered, modifications to these cutoff values are expected. Note that lower rank
bituminous coals are more easily extracted than higher rank coal.
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This test method is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.15 on Metallurgical Properties
of Coal and Coke.
Current edition approved Feb. 1, 2008Jan. 1, 2015. Published April 2008January 2015. Originally published approved in 1992. Last previous edition approved in 20012008
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as D5263 – 93(2001).(2008) . DOI: 10.1520/D5263-93R08E01.10.1520/D5263-15.
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volume information, refer to the standard’s Document Summary page on the ASTM website.
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D5263 − 15
TABLE 1 Guidelines for General Acceptance/Rejection Levels of
Oxidized Coal
Percent Transmittance at
Interpretation of Results
520 nm, 17-mm Light Path
>90 Coal is not oxidized. Suitable for metallurgical
usage.
80 to 90 Coal may be oxidized. If it is being used
metallurgically, it should be monitored
closely for further changes in oxidation.
<80 Coal is oxidized. Coal at this level may cause
coke quality and coke plant operating
problems.
TABLE 1 Guidelines for Ge
...