1、Designation:D526321Standard Test Method forDetermining the Relative Degree of Oxidation in BituminousCoal by Alkali Extraction1This standard is issued under the fixed designation D5263;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,
2、the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This colorimetric test method describes the determina-tion of the relative degree of oxidation by alkali extrac
3、tion ofcoals that are high volatile A bituminous to low volatilebituminous 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 ofweathering.1.3 UnitsThe values stated in SI units are to be regardedas standard.The values given
4、 in parentheses after SI units areprovided for information only and are not considered standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and envi
5、ronmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standa
6、rds,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD7448 Practice for Establishing the Competence of Labora-tories Using ASTM Procedures in the Sampling andAnal
7、ysis of Coal and Coke3.Terminology3.1 There are no terms in this standard that require new orother than dictionary definitions.4.Summary of Test Method4.1 Humic acids,which are present in oxidized coals,areextracted from the coal with sodium hydroxide solution.Thedegree of oxidation is determined by
8、 colorimetrically measur-ing the transmittance of the alkali extract solution at 520 nm.The intensity of the color produced by the humic acids is afunction of the degree of oxidation.5.Significance and Use5.1 This test method is a relative measure of the degree ofoxidation present in coal.It does no
9、t determine the quantitativeamount of oxidized coal present.It is only intended to serve asa guide to the supplier,buyer,and user for selecting coals formetallurgical use.NOTE1Lower rank bituminous coals are more easily extracted thanhigher rank coal.6.Apparatus6.1 Transmission SpectrophotometerSing
10、le-beam,gratingspectrophotometer having a wavelength range of 340 nm to900 nm.6.2 Glass Test Tubes/Cuvettes,with light paths ranging from10 mm to 17 mm may be used.Test tubes with an insidediameter of 17 mm 6 0.3 mm are commonly used.6.3 Analytical Balance,sensitive to 0.001 g.6.4 Hot Plate,capable
11、of bringing aqueous solutions to aboil.6.5 Thermometer,capable of measuring up to 100 C with asensitivity of 6 0.5 C.6.6 Filter Papers,Type II,Class F and G.6.7 Timer,capable of measuring 30 min to the nearestsecond.6.8 Graduated Cylinder,100 mL capacity.6.9 Beakers,400 mL capacity.7.Reagents7.1 Sod
12、ium Hydroxide Solution(certified 1N).7.2 Octylphenoxypolyethoxyethanol Nonionic SurfactantWetting agent.1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D05.15 on MetallurgicalProperties of Coal and Coke.Current editio
13、n approved Dec.1,2021.Published January 2022.Originallyapproved in 1992.Last previous edition approved in 2015 as D5263 15.DOI:10.1520/D5263-21.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volum
14、e information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardizat
15、ion established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.17.2.1 Wetting agent shall not be diluted(100%concentra-tion).8.Calibration and Standardization8.1 O
16、ptical light filters with known absorbance/transmissionshall be used to check wavelength accuracy and linearity of thespectrophotometer.Solutions with accurate absorbance valuescan be found in published literature.38.2 A blank solution consisting of 100 mL of 1N sodiumhydroxide is prepared by following the procedure outlined inSection 9,except coal is not used.9.Procedure9.1 Activate the spectrophotometer and set at 520 nm wave-length;allow sufficient time for the instrument to stabilize(30 min)
