ASTM_D_5671_-_20.pdf

Designation:D567120Standard Practice forPolishing and Etching Coal Samples for MicroscopicalAnalysis by Reflected Light1This standard is issued under the fixed designation D5671;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.Scope1.1 This practice covers laboratory procedures for preparingan etched,polished surface of granular and block samples ofcoal for examination with a microscope using reflected lightillumination.1.2 UnitsThe values stated in SI units are to be regardedas standard.The values given in parentheses after SI units areprovided for information only and are not considered standard.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:2D121 Terminology of Coal and CokeD2797 Practice for Preparing Coal Samples for Microscopi-cal Analysis by Reflected LightD2798 Test Method for Microscopical Determination of theVitrinite Reflectance of CoalD2799 Test Method for Microscopical Determination of theMaceral Composition of CoalD4596 Practice for Collection of Channel Samples of Coalin a MineD5192 Practice for Collection of Coal Samples from Core3.Terminology3.1 Terminology used in this standard can be found inTerminology D121.4.Summary of Practice4.1 A subsplit of a representative sample obtained in accor-dance with Practice D4596 and prepared in accordance withPractice D2797,or a block of coal obtained in accordance withPractice D5192,is polished to a flat,scratch-free surface;thereflectance of vitrinite is determined on a subsplit in accor-dance with Test Method D2798;and then other subsplits arechemically etched using an acidified potassium permanganatesolution.5.Significance and Use5.1 Components observable in surfaces of coal samplesprepared in accordance with the laboratory procedures of thispractice will have differential relief that will aid in theirmaceral identification by visual classification and enablesidentification of plant parts or tissues that formed the coal.5.2 Samples prepared by this practice can be used formicroscopical determination of the volume percent of physicalcomponents of coal in accordance with Test Method D2799.5.3 Samples prepared by this practice can be used for themicroscopical identification of botanical components by tapho-nomic rank.Samples for this purpose should be limited totelovitrinite and semifusinite rich coals of bright lithotype tomaximize feedback from etching.6.Apparatus6.1 Ultrasonic Cleaner,large enough for sample holder andsample preparations to be immersed in cleaning solution.6.2 BeakersGlass beakers of(50,100,and 500)mlcapacity,one each for each etching setup.6.3 Stirring Rods,glass,approximately 20 cm long.6.4 Hot Plate,electric or gas-heated with capability fortemperature control and rotating stirring magnets.6.5 Watch Glasses,glass,100 mm to 200 mm in diameter,depending on size of specimen blocks to be etched.6.6 Graduated Cylinders,glass,(25 and 100)ml.1This practice is under the jurisdiction of ASTM Committee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.28 on PetrographicAnalysis of Coal and Coke.Current edition approved Oct.1,2020.Published November 2020.Originallyapproved in 1995.Last previous edition approved in 2019 as D5671 95(2019).DOI:10.1520/D5671-20.2For 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.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 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.16.7 Grinding and Polishing EquipmentOne or several lapson which the coal briquets or blocks can be ground andpolished to a flat,scratch-free surface.Laps may be made ofaluminum,iron,brass,or bronze.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unl