1、Designation: D 3997 97 (Reapproved 2004)Standard Practice forPreparing Coke Samples for Microscopical Analysis byReflected Light1This standard is issued under the fixed designation D 3997; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers laboratory procedures for thepreparation of granular samples of coke for exami
3、nation witha reflected light microscope. The samples prepared are used foridentifying and quantifying the textural components in coke.This practice does not apply to the preparation of oriented lumpspecimens of coke for structural analysis.1.2 The values stated in SI units are to be regarded as thes
4、tandard. The values given in parentheses are for informationonly.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 appl
5、ica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 121 Terminology of Coal and CokeD 346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD 5061 Test Method for Microscopical Determination ofVolume Percent of Textural Component
6、s in MetallurgicalCokeE 11 Specification for Wire Cloth and Sieves for TestingPurposes3. Terminology3.1 DefinitionsFor additional definitions of terms used inthis practice, refer to Terminology D 121.3.1.1 briquette, na cylindrical block composed of granu-lated coal or coke particles compressed and
7、embedded with anepoxy binder.4. Summary of Practice4.1 A representative sample is crushed to a specified particlesize, oven-dried, mixed with a binder, and formed into a blockspecimen referred to as a briquette. The briquette is thenpolished to a flat, scratch-free surface for microscopical ex-amina
8、tion under reflected light.5. Significance and Use5.1 Briquettes of granular coke prepared in accordance withthe laboratory procedures of this practice will have flat,scratch-free surfaces suitable for examination with a micro-scope using reflected light illumination. The polished surfaceof briquett
9、es prepared using this practice will contain particlesrepresentative of the original gross sample.5.2 Samples prepared by this practice are used for micro-scopical determination of the textural components in coke (seeTest Method D 5061).6. Apparatus6.1 Grinder, Pulverizer, Mill, or Jaw Crusher, or o
10、thersuitable equipment for final crushing of the sample to pass a2.36-mm (No. 8) sieve.6.2 Coarse Riffle Sampler, with at least twelve divisions ofnot less than 12.7 mm (12 in.) and not greater than 19.1 mm (34in.).6.3 Medium Riffle Sampler, with at least twelve divisions ofnot less than 6.4 mm (14
11、in.) and not greater than 12.7 mm (12in.).6.4 SievesA 6.4-mm (14-in.) and 2.36-mm (No. 8) U.S.A.Standard Sieve (see Specification E 11).6.5 MoldsContainers to hold the coke/binder mixturewhile the binder hardens. Generally, steel cylindrical molds areused (see Fig. 1). However, it is acceptable to u
12、se other moldmaterials that successfully yield the same type of briquette.6.5.1 The mold shall be made of separable parts or someother design so that the briquette can be ejected after thebriquette has hardened.6.5.2 The mold shall be large enough to provide a plane areaof4cm2or more on one side of
13、the briquette. (Designs ofsuitable 25- and 32-mm (1- and 114-in.) inside-diameter moldsare shown in Fig. 1).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 edition
14、approved April 1, 2004. Published May 2004. Originallyapproved in 1992. Last previous edition approved in 1997 as D 3997 97.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, r
15、efer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.6 Hydraulic Press, capable of producing a pressure up to28 MPa (4000 psi) on the briquette with an attachment to ejectth
16、e briquette after hardening of the binder.6.7 Grinding and Polishing Equipment, having one orseveral laps on which the coke briquette can be ground andpolished to a flat, scratch-free surface. Laps may be made ofiron, brass, or bronze.NOTE 1Equipment that has 203- or 305-mm (8- or 12-in.) diameterdi
17、sk laps, gear-driven at 160 to 170 r/min, and has an automatic sampleholder attachment is recommended.6.8 Sample Cleaner, essential for cleaning coke briquettesbetween the different grinding or polishing stages. This may bea simple stream of water or an airjet, but an ultrasonic cleaneris recommende
18、d.6.9 ContainersIf samples are to be transported or storedbefore briquettes are prepared, glass jars, bottles, or metal canshaving tight-fitting closures shall be used. Metal cans shallhave plastic liners.7. Materials7.1 BinderAny binding material, such as epoxy resin,fulfilling the following requir
19、ements may be used for preparingthe coke briquette:7.1.1 The binder shall hold all coke particles securelyduring grinding, polishing, and observation.7.1.2 The binder shall not react with the coke or theatmosphere.7.1.3 Under the microscope, the binder shall contrast mark-edly with the coke being ob
20、served when immersed in oil.7.1.4 The binder shall be such that a substantially flat andscratch-free surface can be obtained as a result of the grindingand polishing procedure.NOTE 2Relief, or difference in level, particularly between the cokeand the binder, is undesirable for microscopic observatio
21、n. Relief dependsa great deal on the polishing technique.7.2 Release AgentAny preparation that does not damagethe molds or adversely affect the coke or mounting mediummay be used to coat the inside of the mold and facilitateejection of the briquette.7.3 Grinding AbrasivesWater-resistant, adhesive-ba
22、ckedsilicon carbide papers of grit Nos. 120, 240, 400, and 600. Thegrinding and polishing sequences recommended are listed inTable 1.NOTE 3It is acceptable to use commercially available diamondimpregnated wheels as substitutes particularly for the coarse grindingabrasive papers if the same polish qu
23、ality requirements are met asspecified in Section 10.7.4 Polishing AbrasivesAluminum oxide slurries in 0.3-and 0.05-m sizes. The grinding and polishing sequencesrecommended are listed in Table 1.NOTE 4It is acceptable to use commercially available colloidal silicaas a substitute for aluminum oxide i
24、f the same polish quality requirementsare met as specified in Section 10.7.5 Lap CoveringsNap-free cloths or chemotextile mate-rial backed with water-resistant adhesive.7.6 DetergentAny nonoxidizing detergent may be usedfor cleaning briquettes after each grinding or polishing stage.8. Sampling8.1 Ob
25、tain gross samples of coke in accordance with TestMethod D 346, when appropriate.8.2 If the coke appears wet, oven-dry the coke until nosurface moisture is evident.8.3 Crush and divide the gross sample in accordance withTest Method D 346 to obtain a subsample of 500 g of 2.36-mm (No. 8) sieve size.
26、Particle size reduction is done in sucha manner that the production of fines is minimized.8.4 Pass the dried, sieved coke through the medium rifflesampler (see 6.3) to obtain a sample of about 50 g for a set oftwo briquettes about 25 mm (1 in.) in diameter.8.5 A reserve coke sample should be stored
27、as described in6.9.NOTE 1Material: cold rolled or stainless steel. Dimensions a and b(inside diameters) are nominally 32 and 25 mm. If an automatic polishingattachment is to be used, these dimensions should be specified to yield abriquette fitting snugly in the briquette holder.FIG. 1 Molds Suitable
28、 for Briquetting Coke SamplesTABLE 1 Suggested Abrasive Sequences for Grinding andPolishing Coke BriquettesANOTE 1Alternative abrasives and techniques are permissible if thesame polish quality requirements are met as specified in Section 10.Sequence Igrinding with silicon carbide paper:1. No. 120 gr
29、it paper2. No. 240 grit paper3. No. 400 grit paper4. No. 600 grit paperSequence IIpolishing with alumina on cloths:1. 0.3-m slurry on chemotextile2. 0.05-m slurry on chemotextileD 3997 97 (2004)29. Preparation of Coke Briquettes9.1 Prepare a coke briquette using a binder that meets therequirements o
30、f 7.1 in such a manner that, when polished, atleast 60 % of the cross-sectional area will be coke. A suitableprocedure for use with epoxy resin is as follows:9.1.1 Add activator or hardener, in the amount recom-mended by the supplier, to about4gofepoxy resin for each 10g of coke. Mix thoroughly with
31、 a spatula or disposable woodenstirring stick. Place the riffled coke sample in a suitable smalldisposable container. Thoroughly stir a few drops of resin intothe coke sample. Continue to add resin, a few drops at a time,and stir until all coke particles are wetted and the coke-resinmixture coheres
32、when pressed to the side of the container withthe spatula.9.1.2 Coat the internal surfaces of a mold (including plung-ers if applicable) with a release agent and insert the lowerplunger. Fill the mold with the coke-resin mixture. Insert theupper plunger, place the mold in the hydraulic press, and ap
33、plypressure on the briquette for 3 to 5 s. Pressures of less than 28MPa (4000 psi) have been found to be adequate. Release andreapply the pressure; repeat this cycle three times to expel airbubbles.9.1.3 Allow the briquette(s) to harden overnight at roomtemperature or apply heat to harden as recomme
34、nded by themanufacturer of the epoxy.9.1.4 Eject the coke briquette from the mold using thespecial attachment on the press and label the briquette.NOTE 5It is acceptable to use 32- or 38-mm (114-or112-in.)preformed one-piece molds that do not include separable parts and do notrequire pressure during
35、 the coke-briquetting procedure. This type ofbriquette is commonly referred to as a loose mount. It is also acceptableto use other types of binding material other than the commonly usedactivator/resin-based epoxy. Binding powders used in the proper ratio ofcoke to binder with proper heat treatment h
36、ave also been found accept-able.10. Preparation of Briquette Surface10.1 Grind and polish one of the flat surfaces of thebriquette on a lap to obtain a surface suitable for microscopicalexamination. Grinding and polishing can be done either byhand manipulation or with an automatic attachment. Use as
37、eries of abrasives of decreasing particle size according to aplan such as the one described in Table 1. The surface soobtained shall meet the following requirements:10.1.1 Enough material shall be removed from the briquetteto produce a flat surface over the entire area.10.1.2 The surface shall be fr
38、ee of pits caused by loss ofgrains of coke or mineral matter.10.1.3 The surface shall be reasonably free of scratcheswhen examined at a magnification of 3500 or more under oilimmersion.10.1.4 The surface shall be reasonably free of relief.10.1.5 The surface shall be free of grinding and polishingcom
39、pounds.10.2 After each grinding or polishing step, clean the bri-quette(s) to remove all abrasive and dislodged coke andmineral cuttings. Use of an ultrasonic cleaner filled with waterand detergent is recommended.11. Keywords11.1 briquettes; coke; microscopyASTM International takes no position respe
40、cting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This st
41、andard 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 withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internat
42、ional Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown belo
43、w.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(www.astm.org).D 3997 97 (2004)3
