ASTM_D_5671_-_95_2011.pdf

Designation:D567195(Reapproved 2011)Standard 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 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 and health practices and determine the applica-bility of regulatory limitations prior to use.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 D2799.6.Apparatus6.1 Ultrasonic Cleanerlarge enough for sample holderand sample preparations to be immersed in cleaning solution.6.2 Beakersglass beakers,50,100,and 500 ml capacity,one each for each etching setup.6.3 Stirring Rodsglass,approximately 20 cm long.6.4 Hot Plateelectric or gas-heated with capability fortemperature control and rotating stirring magnets.6.5 Watch Glassesglass,100200 mm in diameter de-pending on size of specimen blocks to be etched.6.6 Graduated Cylindersglass,25 and 100 ml.6.7 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.Unless otherwise indicated,it is intended thatall reagents conform to the specifications of the Committee on1This 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 April 1,2011.Published June 2011.Originallyapproved in 1995.Last previous edition approved in 2005 as D5671-95(2005).DOI:10.1520/D5671-95R11.2For 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 States1 Analytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the quality of theetch.7.2 Potassium Permanganate(KMnO4),crystals.7.3 Sodium Sulfite(Na2SO3),anhydrous,granular.7.4 Sulfuric Acid(H2SO4),47%H2SO4.7.5 Sodium Hydroxide solution,dissolve 10 g NaOH crys-tals in 90 g deionized water at room temperature.8.Materials8.1 Grinding AbrasivesWater-resistant,adhesive-backedsilicon carbide papers of 45,32,and 15 m(240,400,and 600grit).Two or more of these can be used according to a plansuch as one of those listed in Table 1.8.2 Polishing AbrasivesLevigated aluminum oxide pow-ders of 1.0 m size(aqueous suspension)and colloidal silica of0.06 m size(in a prepared NaOH suspension).8.3 Lap Co