1、Designation: D5187 10 (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,
2、 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.1NOTEEditorial changes were made throughout in December 2015.1. Scope1.1 This test method co
3、vers the determination 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 thicknesse
4、s. This test method 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 s
5、tandard. The inch-pound 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 prac
6、tices and determine the 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
7、Gross Sampleof CoalD4057 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 pla
8、teletslocated parallel to one 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 Thet
9、a angle, , nthe glancing angle produced 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
10、monochromatic X-ray beam and rotated 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 pet
11、roleum coke, as reflected by theLcvalue, is a 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
12、affected by coke microporo-sity or the presence of 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 tes
13、t method is under the jurisdiction of ASTM Committee D02 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. Originallypubl
14、ished in 1991. Last previous edition approved in 2010 as D5187 10. 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
15、 Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1processor, and readout (chart or computer memory). Thediffractometer must be capable of rate scanning at 1 2minor incrementally step scanning at 0.2 2 st
16、eps.6.2 Sample Holders, as specified by the manufacturer of thediffractometer 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 Aluminu
17、m 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 reagents shall confor
18、m tothe specifications of the Committee on Analytical Reagents ofthe American Chemical Society where such specifications areavailable.3Other grades may be used, provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy of the dete
19、rmi-nation.7.2 Acetone.7.3 Polyethylene Glycol, (approximate molecular weight of200 AU).7.4 Binding AgentPrepare a 15 % by mass solution ofpolyethylene glycol and acetone by adding 15 g of polyethyl-ene glycol to 85 g of acetone.8. Sample Preparation8.1 For recommended practices for obtaining, handl
20、ing andpreparing coke samples, refer to Test Methods D2013 andD2234/D2234M and Practices D346 and D4057. The equip-ment and procedures for crushing and dividing are alsodescribed in these test methods.8.2 Reduce and divide the gross sample to obtain a labora-tory analysis sample.8.3 Divide, by riffl
21、ing, a minimum of 100 g from thelaboratory analysis sample.8.4 Crush 100 g of the test sample such that 98 % will passthrough a 75 m (No. 200) sieve.8.5 TechniquesAny of the following techniques can beused for packing the sample into the X-ray diffractometerspecimen holder:8.5.1 Back Fill TechniqueP
22、ut the window on a glass slide(Slide 1) and transfer sufficient quantities of sample into thewindow. Work the sample towards the corners of the holder byuse of a glass slide or spatula. Press down using a flat glassslide and scrape off any excess material. Place a glass slide(Slide 2) on top of the
23、sample and secure with tape. RemoveSlide 1 to expose a flat, smooth surface before inserting into thediffractometer for analysis.8.5.2 Front Fill TechniquePlace a confining ring over theround sample holder and fill the holder cavity and ring withsample. The ring will initially overfill the sample ho
24、lder. Workthe sample into the entire cavity and ring. Scrape the excess offwith a glass plate or spatula. Press down using a flat glass slide.Remove any excess material on the front face of the holder.Repress the sample with the glass slide while turning clockwiseand anti-clockwise. Continue until t
25、he sample is level with theholder face. Place the sample in diffractometer holder.8.5.3 Side Loading TechniquePack the sample followingthe procedure used by the National Institute of Standards andTechnology and the Joint Committee on Powder DiffractionStandards to prepare standard powder diffraction
26、 patterns.4Clamp a glass slide over the top face to form a temporarycavity wall. With the holder in a vertical position, drift thepowdered sample into the end opening. If necessary, use acardboard pusher cut to fit the cavity to lightly compress thesample so it will remain in the cavity. Return the
27、holder to ahorizontal position and carefully remove the glass slide. Placethe sample in diffractometer holder.8.5.4 Briquetting TechniqueWeigh out 4.0 g of the sampleonto a watch glass and pipette exactly 3 mL of the bindingagent onto the sample and mix thoroughly with a spatula. Placethe sample und
28、er an infrared heat lamp and allow the acetoneto evaporate. Typically, between 1 min and 2 min will berequired to eliminate the acetone odor from sample. Break upthe caked sample with a spatula and transfer to an aluminumcap whose diameter is compatible with the sample holder of thediffractometer. P
29、lace the cap in a briquetting press and press at48 MPa (7000 psi). Transfer the pelletized sample to thesample holder and insert into the diffractometer for analysis.9. Calibration9.1 Calibration consists of ensuring that the diffractometeris in correct mechanical and optical alignment and intensiti
30、eshave been maximized through the procedures described in theinstrument manufacturers documentation. This is best accom-plished by a service engineer or in-house technician who hasbeen well instructed in the correct alignment proceduressuggested by the manufacturer.9.2 Proper angles and intensities
31、are monitored by a refer-ence material such as NIST silicon and corrective actions takenif necessary.10. Procedure10.1 Prepare and operate the diffractometer in accordancewith the manufacturers instructions. Once established, closelycontrol all instrumental parameters to ensure repeatable analy-ses.
32、10.2 Place the packed sample in the instruments sampleholder and energize the X-ray source.3“Reagent Chemicals, American Chemical Society Specification.” AmericanChemical Society, Washington, D.C. For suggestions on the testing of reagents notlisted by the American Chemical Society, see “Analar Stan
33、dards for LaboratoryU.K. Chemicals,” BDH Ltd., Poole, Dorset, and the “United States Pharamacopeia.”4McMurdie, et al., “Methods of Producing X-Ray Diffraction PowderDiffractions,” Powder Diffraction, Vol 1, No. 1, March 1986.D5187 10 (2015)1210.3 Obtain a diffraction pattern rate scanned at 1 2minor
34、 step scanned at 0.2 2 per step over the range of 14 2 to34 2. Record the data either on a strip chart recorderscanning at 1 min or through computer software designed toread and store the angular and intensity measurements.10.4 For manual interpretation from a strip chart recording,refer to Fig. 1.1
35、0.4.1 Determine the average low and high background(Points A and B, respectively) on the diffraction scan andconnect them with a straight line.10.4.2 Construct Line CD parallel to AB and going throughthe apex of the peak at point G (hkl = 002 at 3.35 A). Drawthe line such that if the peak is irregul
36、ar it will pass through theaverage of the irregularities.10.4.3 Determine the full width half maximum (FWHM) ofthe peak by measuring the vertical distance between CD andAB. Construct Line EF such that it intersects the peak at halfof its maximum value. The points at which EF intersects thepeak are 2
37、1and 22, respectively.10.5 For computer simulation based on the intensities re-corded at 0.2 2 intervals, produce a mathematical represen-tation of the diffraction curve. Determine the baseline, peak,peak height, and half peak height to produce the half peakheight angles, 21and 22, as above.11. Calc
38、ulation11.1 Determine the following parameter:po 5 2 sin 22 sin 1!/ (1)where: = the wavelength of the target material of the X-raytube expressed in angstrom units,1= the angle at the half peak intensity (21/2) width onthe low side, and2= the angle at the half peak intensity (22/2) width onthe high s
39、ide.NOTE 1The latter calculations were derived from the Scherrerequation:Lc5 K!/cos! (2)where:K = an arbitrary constant that is equivalent to 0.89 for Lc, = wavelength of the source radiation measured in angstroms, = line breadth of the pure diffraction peak measured in radians, and = angular locati
40、on of the peak maximum (2/2) measured indegrees.11.2 Determine the mean crystallite height by:Lc5 0.89/po (3)NOTE 2The above calculation makes the assumption that the true linewidth is equal to the measured width, the contribution of instrumental linebroadening is negligible.12. Report12.1 Report th
41、e mean crystallite thickness to the first deci-mal as Lc= xx.x angstroms ().13. Precision and Bias513.1 The values in the precision statement were determinedin a cooperative program following Practice E691. In this 2008study, there were ten laboratories and eight samples.13.2 The precision of this t
42、est method as determined by thestatistical examination of interlaboratory test results in whichone operator in ten laboratories made duplicate analysis oneach of six materials is as follows:13.2.1 RepeatabilityThe difference between successiveresults by the same operator using the same apparatus und
43、erconstant operating conditions on identical test materials will, inthe long run, in normal and correct operation of the testmethod, exceed the following value only in one case in twenty:Repeatability, r = 0.5 13.2.2 ReproducibilityThe difference between two singleand independent results obtained by
44、 different operators work-ing in different laboratories on identical test materials will, inthe long run, in normal and correct operation of the testmethod, exceed the following values only in one case intwenty:Reproducibility, R = 1.9 13.3 BiasSince there is no accepted reference materialsuitable f
45、or determining the bias for the procedure in this testmethod for measuring crystallinity of petroleum coke, bias hasnot been determined.14. Keywords14.1 crystallinity; Lc; petroleum coke; X-ray diffraction5Supporting data have been filed at ASTM International Headquarters and maybe obtained by reque
46、sting Research Report RR:D02-1690.FIG. 1 Typical Diffraction Scan of Petroleum CokeD5187 10 (2015)13ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that dete
47、rmination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or
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49、t your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website
