ASTM_D_2492_-_02_2012.pdf

Designation:D249202(Reapproved 2012)Standard Test Method forForms of Sulfur in Coal1This standard is issued under the fixed designation D2492;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method applies to the determination of sulfatesulfur and pyritic sulfur in coal and calculates organic sulfur bydifference.This test method is not applicable to coke or othercarbonaceous materials.Monosulfides(pyrites and FeS2aredisulfides)of iron and elements such as cadmium,lead,vanadium,and zinc can be present in coal.In the range of 0 to100 ppm,these monosulfides do not contribute significantly tothe total inorganic sulfide content.1.2 The values stated in SI units are to be regarded asstandard.1.3 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD2013 Practice for Preparing Coal Samples for AnalysisD3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD3177 Test Methods for Total Sulfur in theAnalysis Sampleof Coal and CokeD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different BasesD4239 Test Method for Sulfur in the Analysis Sample ofCoal and Coke Using High-Temperature Tube FurnaceCombustionE832 Specification for Laboratory Filter Papers3.Summary of Test Method3.1 Sulfate Sulfur:3.1.1 Sulfate sulfur is extracted from the analysis samplewith dilute hydrochloric acid.The sulfate sulfur in the extractis determined gravimetrically.Sulfates are soluble in hydro-chloric acid,but pyritic and organic sulfur are not.3.2 Pyritic Sulfur:3.2.1 Pyritic sulfur is calculated as a stoichiometric combi-nation with iron.3.2.2 Methods:3.2.2.1 Referee Method,which can be used in cases ofdispute or arbitration.The iron combined in the pyritic state isextracted with dilute nitric acid from the coal residue remain-ing after sulfate extraction(see Note 1).The iron is determinedby atomic absorption techniques(see Note 2).NOTE1The sulfate extraction step also removes hydrochloric acidsoluble iron(nonpyritic iron)from the test specimen.A test specimenseparate from that used for the sulfate extraction could be used for thenitric acid extraction of iron.In this case,both nonpyritic and pyritic ironare extracted from the test specimen.Since there is evidence that for somecoals the extraction of nonpyritic iron by nitric acids falls short of theamount extracted by hydrochloric acid,3,4the use of a separate testspecimen for the nitric acid extraction of iron with subsequent correctionfor the contribution of nonpyritic iron is not included in this test method.NOTE2Round-robin testing of the coal samples used to generate datafor the precision statement in this test method indicates that plasmaemission techniques give results equivalent to those from atomic absorp-tion analysis for the determination of iron.However,emission analysis ishighly susceptible to interferences from other analytes that may bedissolved during the extraction of iron.Selection of a wavelength that isfree from interferences and linear over the range of iron anticipated foremission analysis can require a detailed compositional analysis of the coalmineral matter,thus limiting the practicality of this approach.3.2.2.2 Alternative Method,which can be used in routinepractice or when the concerned parties agree on this testmethod.The iron originally combined in the pyritic state canbe extracted with dilute hydrochloric acid from the ashobtained by incinerating the coal residue remaining after1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D05.21 on Methods ofAnalysis.Current edition approved Sept.1,2012.Published November 2012.Originallyapproved in 1966.Last previous edition approved in 2007 as D2492 02(2007).DOI:10.1520/D2492-02R12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Edwards,A.H.,Daybell,G.N.,and Pringle,W.J.S.,“An Investigation intoMethods for the Determination of Forms of Sulfur in Coal,”Fuel,Vol 37,1958,pp.4759.4Burns,M.S.,“Determination of Pyritic Sulfur in Australian Coals,”Fuel,Vol49,1970,pp.12633.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 sulfate