1、Designation:D2797/D2797M11aStandard 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 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivale
4、nts;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address the safetyconcerns associated with its use.It is the responsibility of theuser of this standard to estab
5、lish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:2D2013 Practice for Preparing Coal Samples for AnalysisD2234/D2234M Practice for Collection of a Gross Sampleof CoalD2798 Test Method for Micro
6、scopical 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 Woven Wire Test Sieve Cloth and TestSieves3.Summary of Practice3.1 Arepr
7、esentative 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 Use4.1 Briquets of granular bituminous coals and anthraciteprepared
8、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 practicewill contain particles representative of the original grosssam
9、ple.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 percent ofphysical components of coal(Test Method D2799).5.Apparatus5.1
10、 Grinder,Pulverizer,or Mill,for final crushing of thesample to pass a 850-m(No.20)sieve.Mortar and pestle orother equipment suitable for reducing the particle size of a250-g sample that already passes a 4.75-mm(No.4)sieve untilall of it passes a 850-m(No.20)sieve(see 6.5).5.2 Coarse Riffle Samplera
11、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.and not greater than 6.4mm 14in.5.4 Sievesa 4.75-mm(No.4)and a 850-m(No.20)U.S.Standard Sieve(Specification
12、 E11).5.5 Moldscontainers to hold the coal binder mixture whilethe 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 large enough to prov
13、ide a plane areaof 4 cm2or more on one side of the briquet.(Designs of1This 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 June 1,2011.Published July 20
14、11.Originally approvedin 1969.Last previous edition approved in 2011 as D2797 11.DOI:10.1520/D2797_D2797M-11A.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 standar
15、ds Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 suitable 25-mm 1-in.and 32-mm 114-in.inside-diametermolds are shown in Fig.1).5.6 Mounting Pressa manual or automated press that iscapable of prod
16、ucing a pressure up to 35 MPa 5000 psi on thebriquet,and has an attachment to eject the briquet aftersolidification of the binder.Aheat-setting automated press shallbe used with an appropriate thermoset binder.5.7 Grinding and Polishing Equipmentone or several lapson which the coal briquet can be ground and polished to a flat,scratch-free surface.Laps may be made of aluminum,iron,brass,bronze,lead,glass,wax,or wood.Equipment that has203-mm 8-in.diameter disk laps,gear-driven at 160 to 170r/min,a
