1、Designation: D3997/D3997M 16Standard Practice forPreparing Coke Samples for Microscopical Analysis byReflected Light1This standard is issued under the fixed designation D3997/D3997M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision,
2、the 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 and lump coke into briquette and
3、 blocksamples for examination with a reflected light microscope. Thesamples prepared are used for examination and identification ofthe components in coke and the measurement of the reflectanceof coke.NOTE 1Sieve size is identified by its standard designation in Speci-fication E11. The alternative de
4、signation given in parentheses is forinformation only and does not represent a different standard sieve size1.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. Thevalues stated in each system may not be exact equivalents;therefore, each system
5、 shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.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
6、appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD5061 Test Method for Micros
7、copical Determination of theTextural Components of Metallurgical CokeE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Definitions:3.1.1 For additional definitions of terms used in thispractice, refer to Terminology D121.3.1.2 block, npiece of sectioned lump coke or c
8、okedrillcore embedded in sample binder.3.1.3 briquette, ncylindrical block composed of granu-lated coal or coke particles compressed and embedded with anepoxy binder.4. Summary of Practice4.1 Arepresentative sample is crushed to a specified particlesize, oven-dried or after air-drying, mixed with a
9、binder, andformed into a block specimen referred to as a “briquette.”4.2 Alternatively, a sectioned lump of coke, or coke drillcore, oven-dried or after air-drying, is embedded in a suitablebinder and formed into a block specimen referred to as a“block.”4.3 The briquette or block is then polished to
10、 a flat,scratch-free surface for microscopical examination under re-flected light.5. Significance and Use5.1 Briquettes and blocks of coke prepared in accordancewith the laboratory procedures of this practice will have flat,scratch-free surfaces suitable for examination with a micro-scope using refl
11、ected light illumination. The polished surfaceof the samples prepared using this practice will containparticles representative of the original gross sample. Polishedblocks of coke will preserve the porosity and undisturbeddistributions of carbon forms required in the production ofsequences of stitch
12、ed and tiled image mosaics. Such images arerequired for microscopic porosity measurement.5.2 Samples prepared by this practice are used for micro-scopical determination of the textural components in coke (seeTest Method D5061) and the measurement of coke reflectance.6. Apparatus6.1 Grinder, Pulveriz
13、er, Mill, or Jaw Crusher, or othersuitable equipment for final crushing of the sample to pass a2.36-mm (No. 8) U.S. Standard Sieve.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 an
14、d Coke.Current edition approved Oct. 1, 2016. Published October 2016. Originallyapproved in 1992. Last previous edition approved in 2009 as D3997 97(2009).DOI: 10.1520/D3997_D3997M-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm
15、.org. For Annual Book of 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 States16.2 Coarse Riffle Sampler, with at least twelve divisions ofnot
16、 less than 12.7 mm 12 in. and not greater than 19.1 mm34 in.6.3 Medium Riffle Sampler, with at least twelve divisions ofnot less than 6.4 mm 14 in. and not greater than 12.7 mm12 in.6.4 Circular Sample Saw, with a diamond blade at least240 mm 10 in. in diameter, capable of cutting a large piece ofco
17、ke perpendicular to growth lines in one pass.6.5 Drill Press, with a hollow diamond drill bit with aninternal diameter capable of producing cored samples of coke,perpendicular to growth lines.6.6 SievesA 6.4 mm 14 in. and 2.36 mm (No. 8) U.S.Standard Sieve (see Specification E11).6.7 MoldsContainers
18、 to hold the coke/binder mixturewhile the binder hardens. These may be steel cylindrical molds,or reuseable plastic or silicone-rubber molds (see Fig. 1).Molds made of other materials are acceptable, providing thatbriquettes and blocks can be successfully polished.6.7.1 The mold shall be so designed
19、 that the briquette orblock can be ejected after the briquette or block has hardened.6.7.2 The mold shall be large enough to provide a plane areaof4cm2or more on one side of the briquette. (Designs ofsuitable 25- and 32 mm 1 and 114 in. inside-diameter moldsare shown in Fig. 1). Molds of 50 mm 2 in.
20、 90 mm 3.5 in. 35 mm 1.4 in. are suitable for blocks.6.8 Hydraulic Press, capable of producing a pressure up to28 MPa 4000 psi on the briquette with an attachment to ejectthe briquette after hardening of the binder.6.9 Grinding and Polishing Equipment, having one orseveral laps on which the coke bri
21、quette can be ground andpolished to a flat, scratch-free surface. Laps may be made ofiron, brass, or bronze. Equipment that has 203 or 305 mm 8 or12 in. diameter disk laps, gear-driven at 160 to 170 r/min, andhas an automatic sample holder attachment is recommended.6.10 Sample Cleaner, essential for
22、 cleaning coke briquettesbetween the different grinding or polishing stages. This may bea simple stream of water or an airjet, but an ultrasonic cleaneris recommended.6.11 ContainersIf samples are to be transported or storedbefore briquettes are prepared, a suitable container should beselected to ke
23、ep the sample safe from contamination ordegradation.7. Materials7.1 BinderAny binding material, such as epoxy, polyesterresin, or polymethacrylate (PMMA), fulfilling the followingrequirements may be used for preparing the coke briquette orblock:7.1.1 The binder shall hold all coke particles securely
24、during 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 observed when immersed in oil.7.1.4 The binder shall be such that a substantially flat andscratch-free surfa
25、ce 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 observation. Relief dependsa great deal on the polishing technique.7.2 Release AgentAny preparation that does not da
26、magethe 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-backedsilicon carbide papers of size 120 m (Grit No. 120), 54 m(Grit No. 240), 24 m (Grit No. 400), and 16 m
27、 (Grit No.600). The grinding and polishing sequences recommended arelisted in Table 1.NOTE 3It is acceptable to use commercially available diamond-impregnated wheels as substitutes, particularly for the coarse grindingabrasive papers if the same polish quality requirements are met asspecified in Sec
28、tion 10.7.4 Polishing AbrasivesAluminum oxide slurries or dia-mond suspensions in 0.3 m 1 10-5in. and 0.05 2 10-6in.grain sizes. The grinding and polishing sequences recom-mended are listed in Table 1.NOTE 4It is acceptable to use commercially available colloidal silicaas a substitute for aluminum o
29、xide if the same polish quality requirementsare met as specified in Section 10.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
30、fitting snugly in the briquette holder.FIG. 1 Molds Suitable for Briquetting Coke SamplesD3997/D3997M 1627.5 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 p
31、olishing stage.Care shall be given to selection of the detergent to ensure thatno residual stains remain on coke surfaces.8. Sampling8.1 Obtain gross samples of coke in accordance with TestMethod D346, when appropriate.8.2 If the coke appears wet, oven-dry the coke until nosurface moisture is eviden
32、t.8.3 Crush and divide the gross sample in accordance withTest Method D346 to obtain a subsample of 500 g 18 ozof 2.36 mm (No. 8) sieve size. Particle size reduction is donein such a manner that the production of fines is minimized.8.4 Pass the dried, sieved coke through the medium rifflesampler (se
33、e 6.3) to obtain a sample of about 50 g 1.8 oz fora set of two briquettes about 25 mm 1 in. in diameter.8.5 A reserve coke sample should be stored as described in6.11.9. Preparation of Coke Briquettes9.1 Prepare a coke briquette using a binder that meets therequirements of 7.1 in such a manner that,
34、 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 about 4 g 0.14 oz of epoxy resinfor each 10 g 0.35 oz of coke. Mix thoroughly with a spatu
35、laor disposable wooden stirring stick. Place the riffled cokesample in a suitable small disposable container. Thoroughlystir a few drops of resin into the coke sample. Continue to addresin, a few drops at a time, and stir until all coke particles arewetted and the coke-resin mixture coheres when pre
36、ssed to theside of the container with the 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 applypress
37、ure on the briquette for 3 to 5 s. Pressures of less than28 MPa 4000 psi have been found to be adequate. Releaseand reapply the pressure; repeat this cycle three times to expelair bubbles.9.1.3 Allow the briquette(s) to harden overnight at roomtemperature or apply heat to harden as recommended by th
38、emanufacturer 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 or 112 in. preformedone-piece molds that do not include separable parts and do not requirepressure during the coke-br
39、iquetting procedure. This type of briquette iscommonly referred to as a loose mount. It is also acceptable to use othertypes of binding material other than the commonly used activator/resin-based epoxy. Binding powders used in the proper ratio of coke to binderwith proper heat treatment have also be
40、en found acceptable.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 aseries of abr
41、asives 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 free of pits c
42、aused by loss ofgrains of coke or mineral matter.10.1.3 The surface shall be reasonably free of scratcheswhen examined at a magnification of 500 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 polishingcompounds.10.2 A
43、fter 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; microscopyTABLE 1 Suggested Abrasive Sequences for Grinding andPo
44、lishing Coke BriquettesANOTE 1Alternative abrasives and techniques are permissible if thesame polish quality requirements are met as specified in Section 10. Foradvertising purposes, most manufacturers specify polishing compounds inSI units.Sequence IGrinding with silicon carbide paper:1.) 120 m (Gr
45、it No. 120)2.) 54 m (Grit No. 240)3.) 24 m (Grit No. 400)4.) 16 m (Grit No. 600)Sequence IIPolishing with alumina on cloths:1.) 0.3 m 110-5in. slurry on chemotextile2.) 0.05 m 210-6in. slurry on chemotextileAutomated Polishing TechniquesSequence I Grinding with a diamond grinding disk1.) 160 m 610-3
46、in. diamond grinding disk4min, with 200 kPa 30 psi2.) 70 m 310-3in. diamond grinding disk4 min, 100 kPa 15 psi3). 15 m 610-4in. diamond grinding disk6 min, 100 kPa 15 psi4.) 3 m 110-4in. diamond grinding disk6 min, 100 kPa 15 psi5.) 0.5 m 210-5in. diamond grinding disk6 min, 100 kPa 15 psiSequence I
47、I - Polishing with Alumina Slurry (automated system)1.) 0.3 m 110-5in. slurry on chemotextile2 min, 100 kPa 15 psi2.) 0.05 m 210-6in. slurry on chemotextile2 min, 100 kPa 15 psiD3997/D3997M 163ASTM International takes no position respecting the validity of any patent rights asserted in connection wi
48、th 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 standard is subject to revision at any time by the responsible tech
49、nical 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 International 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
