1、Designation:D518710(Reapproved 2015)1Standard Test Method forDetermination of Crystallite Size(Lc)of Calcined PetroleumCoke by X-Ray Diffraction1This standard is issued under the fixed designation D5187;the number immediately following the designation indicates the year oforiginal adoption or,in the
2、 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.1NOTEEditorial changes were made throughout in December 2015.1.Scope1.1 This test method covers the dete
3、rmination of the meancrystallite thickness of a representative,pulverized sample ofcalcined petroleum coke by interpretation of a X-ray diffractionpattern produced through conventional X-ray scanning tech-niques.1.2 Calcined petroleum coke contains crystallites of differ-ent thicknesses.This test me
4、thod covers the determination ofthe average thickness of all crystallites in the sample byempirical interpretation of the X-ray diffraction pattern.Thecrystallite diameter(La)is not determined by this test method.1.3 The values stated in SI(metric)units are to be regardedas the standard.The inch-pou
5、nd units given in parentheses areprovided for information purposes only.1.4 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
6、applica-bility of regulatory limitations prior to use.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 CoalD4057
7、Practice for Manual Sampling of Petroleum andPetroleum ProductsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 crystallites,nstacks of graphitic carbon plateletslocated parallel to o
8、ne another.3.1.2 Lc,nthe mean or average thickness of crystallites ina sample.It is expressed as a linear dimension in angstromunits,A(101nm).3.1.3 hkl(002),nthe Miller indices of the crystallineplanes of graphite corresponding to a lattice spacing(d)of3.35.3.1.4 Theta angle,nthe glancing angle prod
9、uced whena parallel beam of uniform X-rays impinges upon a crystallinelattice.This angle is measured by the X-ray goniometer and isusually expressed in degrees TwoTheta (2).4.Summary of Test Method4.1 A packed sample pulverized to less than 75 m issubjected to a monochromatic X-ray beam and rotated
10、toproduce a diffraction pattern under specific conditions.Thelocation and shape of the peak with hkl=(002)at d=3.35 Ais used to calculate the Lcby manual interpretation of the peakor by computer simulation.5.Significance and Use5.1 The crystallinity of petroleum coke,as reflected by theLcvalue,is a
11、general measure of quality affecting suitability forend use and is a function of the heat treatment.5.2 The crystallite thickness is used to determine the extentof such heat treatment,for example,during calcination.Thevalue of the Lcdetermined is not affected by coke microporo-sity or the presence o
12、f foreign,non-crystalline materials suchas dedust oil.6.Apparatus6.1 X-Ray Powder Diffractometer,equipped with an X-raysource,a monochromator or filter for restricting the wave-length range,a sample holder,a radiation detector,a signal1This test method is under the jurisdiction of ASTM Committee D02
13、 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 Oct.1,2015.Published December 2015.Originallypublished in 1991.Last previous edition approved in 2010 as D5187 1
14、0.DOI:10.1520/D5187-10R15E01.2For 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
15、 Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 processor,and readout(chart or computer memory).Thediffractometer must be capable of rate scanning at 1 2 minor incrementally step scanning at 0.2 2 steps.6.2 Sample Holders,as specified by the manufacturer of thediffractometer
16、 that enables packing of a pulverized sample ofsufficient thickness to expose a level,smooth surface to theX-ray beam.6.3 Briquetting Press,capable of generating pressures up to69 MPa(10 000 psi).6.4 Compressible Aluminum Caps,used as a support forproducing a briquetted sample.6.5 Silicon or Quartz Sample,available from NationalInstitute of Standards and Technology(NIST).7.Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.It is intended that all reagen
