1、Designation:D2797/D2797M21aStandard Practice forPreparing Coal Samples for Microscopical Analysis byReflected Light1This standard is issued under the fixed designation D2797/D2797M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the
2、year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers laboratory procedures for thepreparation of granular samples of bituminous coal and anthra-cit
3、e samples for examination with a microscope using reflectedlight illumination.It does not apply to the preparation oforiented blocks of coal.1.2 UnitsThe values stated in either SI units or non-SIunits are to be regarded separately as standard.The valuesstated in each system are not necessarily exac
4、t equivalents;therefore,to ensure conformance with the standard,eachsystem shall be used independently of the other,and valuesfrom the two systems shall not be combined.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of t
5、he 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
6、 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:2D2013 Practice for Preparing Coal Samples for AnalysisD2234/D2234M Practi
7、ce for Collection of a Gross Sampleof CoalD2798 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 MineE11 Specification for Wov
8、en Wire Test Sieve Cloth and TestSieves3.Summary of Practice3.1 Arepresentative sample is crushed to a specified particlesize,air-dried,mixed with a binder,and formed into a briquet.The briquet is then polished to a flat,scratch-free surface forexamination by vertical illumination.4.Significance and
9、 Use4.1 Briquets of granular bituminous coals and anthraciteprepared in accordance with the laboratory procedures of thispractice will have flat,scratch-free surfaces suitable for exami-nation with a microscope using reflected light illumination.The polished surfaces of briquettes prepared by this p
10、racticewill contain particles representative of the original grosssample.4.2 Samples prepared by this practice are used for micro-scopical determination of the reflectance of the organic com-ponents in a polished specimen of coal(Test Method D2798)and for microscopical determination of the volume pe
11、rcent ofphysical components of coal(Test Method D2799).5.Apparatus5.1 Grinder,Pulverizer,or Mill,for final crushing of thesample to pass a 850 m No.20 U.S.Standard Sieve.Mortarand pestle or other equipment suitable for reducing the particlesize of a 250 g sample that already passes a 4.75 mm No.4U.S
12、.Standard Sieve until all of it passes a 850 m No.20U.S.Standard Sieve(see 6.5).5.2 Coarse Riffle SamplerA riffle with at least twelvedivisions of not less than 12.7 mm 12in.and not greater than19.1 mm 34in.5.3 Fine Riffle SamplerA riffle with at least twelve divi-sions of not less than 3.2 mm 18in.
13、and not greater than6.4 mm 14in.5.4 SievesA 4.75 mm No.4 and a 850 m No.20 U.S.Standard Sieve(Specification E11).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 edi
14、tion approved Sept.1,2021.Published September 2021.Originallyapproved in 1969.Last previous edition approved in 2021 as D2797/D2797M 21.DOI:10.1520/D2797_D2797M-21A.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book o
15、f 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 princ
16、iples 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.15.5 MoldsContainers to hold the coal binder mixturewhile the binder hardens.5.5.1 The mold shall be capable of withstanding pressuresup to 70 MPa 10 000 psi,and shall be made of separable partsso that the briquet can be ejected after it has hardened.5.5.2 The mold shall be larg
