ASTM_D_6791_-_22.pdf

Designation:D679122Standard Test Method forDetermination of Grain Stability of Calcined PetroleumCoke1This standard is issued under the fixed designation D6791;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.1.Scope*1.1 This test method covers a laboratory vibration millmethod for the determination of the grain stability of calcinedpetroleum coke for the manufacture of carbon products used inthe smelting of aluminum.Calcined petroleum coke with poormechanical strength may become degraded during mixing.Poor grain stability will affect the grain size and may result inpoor quality of baked blocks.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 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 Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD2013 Practice for Preparing Coal Samples for AnalysisD2234/D2234M Practice for Collection of a Gross Sampleof CoalD6969 Practice for Preparation of Calcined Petroleum CokeSamples for AnalysisD6970 Practice for Collection of Calcined Petroleum CokeSamples for AnalysisE11 Specification for Woven Wire Test Sieve Cloth and TestSieves2.2 ISO Standard:3ISO 6375 Carbonaceous Materials for the Production ofAluminumCoke for ElectrodesSampling3.Terminology3.1 Definitions:3.1.1 calcined petroleum coke,npetroleum coke that hasbeen thermally treated to drive off the volatile matter and todevelop crystalline structure.3.1.2 petroleum coke,nsolid,carbonaceous residue pro-duced by thermal decomposition of heavy petroleum fractions,or cracked stocks,or both.4.Summary of Test Method4.1 A representative sample of calcined petroleum coke isdried and screened to a 4 mm to 8 mm fraction.The resultantsample is weighed so that two separate portions of 100.0 g 60.5 g mass are obtained.The samples are place into thelaboratory mill and ground for a specified period of time.Aftergrinding the sample is screened and the mass of the+4 mmmaterial is determined.The grain stability is the percent of theoriginal material remaining on the+4 mm sieve.5.Significance and Use5.1 The grain stability of calcined petroleum coke deter-mines the resistance to breakdown of+4 mm particles used inthe manufacture of carbon anodes for use in the reductionprocess of aluminum.5.2 Calcined petroleum cokes have to be relatively easy togrind for fines production but strong enough to withstandforming pressures and thermal stresses occurring when theanodes are used in the reduction process.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels,Petroleum Coke and Carbon Material.Current edition approved May 1,2022.Published May 2022.Originallyapproved in 2002.Last previous edition approved in 2017 as D6791 11(2017)1.DOI:10.1520/D6791-22.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright 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 standardization 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.16.Interferences6.1 No material normally applied to the calcined petroleumcoke is found to cause analytical interference with this proce-dure.7.Apparatus7.1 Analytical Balance,accurate to 6 0.1 g.7.2 Rifflers,with hoppers and closures.7.3 Wire Sieves,8 mm(516in.)and 4 mm(5 mesh),meetingSpecification E11.7.4 Laboratory Vibration Mill4,having two grindingvessels,each filled with 1 kg of clean,ha