1、Designation: D2799 10Standard Test Method forMicroscopical Determination of the Maceral Composition ofCoal1This standard is issued under the fixed designation D2799; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the equipment and techniquesused for determining the physical composition of a coal samplein terms
3、of volume percent of the organic components and ofmineral matter, if desired.1.2 The term weight is temporarily used in this test methodbecause of established trade usage. The word is used to meanboth force and mass and care must be taken to determine whichis meant in each case (the SI unit for forc
4、e is newton and formass, kilogram).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 applica-bility of regulatory limit
5、ations prior to use.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD2797 Practice for Preparing Coal Samples for Microscopi-cal Analysis by Reflected LightD2798 Test Method for Microscopical Determination of theVitrinite Reflectance of CoalD3174 Test Method for Ash in th
6、e Analysis Sample of Coaland Coke from CoalD3177 Test Methods for Total Sulfur in the AnalysisSample of Coal and CokeE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology
7、3.1 DefinitionsFor definitions of terms, refer to Terminol-ogy D121.3.2 ClassificationThe classification of the microscopicconstituents into groups of similar properties in a given coal isas follows:Maceral Group MaceralVitrinite Liptinite or (exinite) alginitecutiniteresinitesporiniteInertinite fus
8、initeinertodetrinitemacrinitemicrinitefunginitesecretinitesemifusinite3.3 Many laboratories associated with the coke-makingindustry use the following simplified classification for petro-graphic analysis of bituminous coal:vitriniteliptinite (other than resinite)resinitesemifusinitemicrinitefusinitem
9、ineral matter3.4 Definitions of Terms Specific to This Standard:3.4.1 alginite, na liptinite maceral that is generally spheri-cal or ovoid, frequently having a crenulated border andsomewhat irregular reflectance and sometimes occurring inclusters reflecting an origin from Botryococcus algae.3.4.1.1
10、DiscussionAlginite often occurs as degraded frag-ments derived from colonial or unicellular bodies.3.4.2 cutinite, na liptinite maceral in the form of a sheetreflecting its origin from leaf- or twig-covering plant cuticle,frequently exhibiting reticulation in planar section and aserrated edge in cro
11、ss section.1This test method is under the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D05.28 on PetrographicAnalysis of Coal and Coke.Current edition approved Sept. 1, 2010. Published September 2010. Originallyapproved in 1969. Last previous ed
12、ition approved in 2009 as D2799 09. DOI:10.1520/D2799-10.2For 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.1Cop
13、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.4.3 exinite, nDeprecated term. Use preferred term lip-tinite; sometimes has also been used as a synonym forsporinite.3.4.4 funginite, nan inertinite maceral occurring as roundor ovoid bod
14、ies, frequently containing voids, reflecting anorigin from fungal sclerotia; also occurs (especially in lowerrank coals) as interlaced, stringy materials derived from fungalhyphae.3.4.5 fusinite, nan inertinite maceral distinguished princi-pally by the preservation of some feature(s) of the plant ce
15、llwall structure, and with a particle size greater than 50 mexcept when it occurs as a fragment within the binder matrix;see also semifusinite.3.4.6 inertinite, nmacerals that exhibit higher reflectancethan other organic substances in the coal.3.4.6.1 DiscussionIn any coal ranked lower than anthra-c
16、itic, inertinite reflectance commonly spans the range fromonly slightly higher than associated vitrinite to very highreflectance (often as high as Ro$6 %). In anthracitic rankcoals, inertinite reflectance may be lower than that of vitrinite,and is then recognized by its morphology and form ofanisotr
17、opy. Highly reflecting inertinite commonly exhibitsrelief on polished surface. Its name derives from the fact thatmost varieties behave inertly in the thermoplastic deformationduring the coking process (except in its lowest reflectingmanifestation). The volatile matter yield of inertinite is lowerth
18、an that of other macerals in the same coal.3.4.7 inertodetrinite, nan inertinite maceral occurring asindividual, angular, clastic fragments incorporated within thematrix of other macerals (commonly vitrinite) or minerals, andin the size range from 2 to 50 m.3.4.8 liptinite, nmacerals that exhibit lo
19、wer reflectancethan other organic substances in a coal, appearing black to darkgray and that fluoresce under blue to ultraviolet light in coalsranked high volatile bituminous and lower.3.4.8.1 DiscussionThe fluorescence of liptinite distin-guishes fine-grained liptinite from similar sized, low refle
20、c-tance, nonfluorescing clay minerals. Liptinite is derived prin-cipally from lipid substances forming skins (exines) andresinous secretions or exudates of plants. Liptinite is sub-classified on the basis of morphology inherited from plantstructure. In coals in which vitrinite reflectance exceeds ab
21、out1.4 %, liptinite can be indistinguishable from vitrinite. Liptinitehas the highest volatile matter yield of the macerals in a coal.3.4.9 maceral, nan organic substance in coal that isdistinguished and classified (see maceral classification)onthebasis of its optical microscopic properties.3.4.9.1
22、DiscussionMacerals originate from plant tissues,secretions, and exudates that have been altered by geologicalprocesses and may contain up to several weight percent ofinorganic elements in microscopically indistinguishable form.3.4.10 maceral classification, nThe systematic division ofthe organic sub
23、stances (macerals) in coal based on theirappearance in the optical microscopic.3.4.10.1 DiscussionAlthough macerals may be identifiedin translucent, thin sections using criteria not defined herein,this test method deals only with identification and classificationbased on microscopic appearance on po
24、lished surfaces accord-ing to Practice D2797. Three major maceral groups arerecognized on the basis of relative reflectance in white light,specifically: vitrinitemoderately reflecting (intermediategray), liptinitepoorly reflecting (black to dark gray), andinertinitehighly reflecting (light gray to w
25、hite). Each groupcan be subdivided on the basis of other microscopicallydistinctive features such as: reflectance contrasts (relativeshades of gray); morphology, that is, shape and size (morpho-logic distinctions in definitions contained herein are idealizedbecause morphologic appearance depends on
26、the initial form ofthe source material, its state of preservation, including granu-lation, and on the orientation of the cross section presented onthe polished preparation); spatial association with other sub-stances; fluorescence properties (color, intensity) in blue toultraviolet light; relief; co
27、lor tinges; internal reflections; andanisotropic properties.Microscopic criteria provide classification capability with-out any implication of absolute chemical composition orphysical behavior, although some properties relative to othermacerals in the same coal can be inferred broadly. Substancescla
28、ssified as the same maceral by microscopic criteria candiffer chemically, physically, and behavioristically in coals ofdifferent ranks. Some properties can be estimated by themeasurement of reflectance (Test Method D2798).See 3.3 for the classification used by most practitioners ofthis test method.3
29、.4.11 macrinite, nan inertinite maceral, generally nonan-gular, exhibiting no relict plant cell wall structure and largerthan 10 m.3.4.12 micrinite, nan inertinite maceral, generally nonan-gular, exhibiting no relict plant cell wall structure, smaller than10 m and most commonly occurring as particle
30、s around 1- to5-m diameter.3.4.13 mineral matter, nin coal, historically considered tobe the non-organic fraction composed of physically discreteparticles of minerals, such as clays, quartz, pyrite, etc., and allelements other than, carbon, hydrogen, oxygen, nitrogen, andsulfur in the organic fracti
31、on.3.4.14 resinite, na liptinite maceral occurring as rounded,ovoid, or rod-like bodies assuming the shape of an enclosingcell lumen or as irregular shapes filling cracks in the coal.3.4.15 secretinite, nan inertinite maceral occurring asround, ovoid, or oblong bodies, without obvious plant struc-tu
32、re, vesicled to non-vesicled, sometimes containing character-istic fractures, slits, or a notch.3.4.15.1 DiscussionSecretinite is considered to be derivedby the oxidation of plant resin secretions or humic gels.Vesicular and non-vesicular secretinite was formerly includedin sclerotinite of fungal or
33、igin. Secretinite is a commonmaceral in medium- and high-rank Permian and Carboniferouscoals.3.4.16 semifusinite, nan inertinite maceral with morphol-ogy like fusinite sometimes with less distinct evidence ofcellular structure, but with reflectance ranging from slightlygreater than that of associate
34、d vitrinite to some value interme-diate to that of the brightest fusinite. The particle size is alsogreater than 50 m except when it occurs as a fragment withinthe binder matrix.D2799 1023.4.16.1 DiscussionThe precise reflectance boundary be-tween semifusinite and fusinite has not been universallyde
35、fined, although some practitioners place the division atRo = 2.0 %; hence, semifusinite is somewhat vaguely definedas “fusinite with low reflectance.”3.4.17 sporinite, na liptinite maceral exhibiting variouslenticular, oval, or round forms that reflect the cross-sectioningof a flattened, hollow, ovo
36、id body; sometimes exhibits rod-likeprojections that are small relative to the size of the total body.3.4.17.1 DiscussionSporinite originated as a lipid sub-stance that covered, as a skin, ovoid spore or pollen grainswhich commonly ranged from around ten to several hundredmicrometres in diameter. Sp
37、orinite often occurs as fragmentsderived from these initially ovoid bodies.3.4.18 vitrinite, nthe predominant maceral in most coalsof intermediate reflectance occurring as substantial volumes ofmore or less uniformly reflecting material or as a matrixenclosing particles of other macerals and mineral
38、 matter or asparticles or bands intermixed with other maceral fragments.3.4.18.1 DiscussionBecause most vitrinite is derivedfrom the cellular, structural tissues of plants, it may exhibitrelict cell structure. The reflectance of vitrinite is related to therank of the coal in which it is found. Refle
39、ctance increases(from around Ro = 0.3 % in lignitic coals) in parallel with theincrease in fixed carbon yield associated with increasing rank.Because many of the properties of typical coals reflect theproperties of the dominating vitrinite, it is common practice toestimate coal properties and proces
40、s behaviors by measuringthe reflectance of a representative sampling of vitrinite in thespecimen according to procedures described in Test MethodD2798.Pseudovitrinite, a certain variety of vitrinite, is differentiatedby some practitioners. It exhibits slightly higher reflectancethan most of the vitr
41、inite in the coal and is commonly slitted,with indistinct remnant cell structure and angular or jaggededges. Pseudovitrinite has been postulated to be less thermo-plastic in the coking process.The term vitrinite is currently used as both a maceral andmaceral group.4. Summary of Test Method4.1 The co
42、mponents in a representative crushed coalsample, prepared as prescribed in Practice D2797, are identi-fied under a microscope according to their reflectance, otheroptical properties, and morphology. The proportions of thesecomponents in a sample are determined by observing astatistically adequate nu
43、mber of points, and summing thoserepresentative of each component. Only area proportions ofcomponents are determined on a surface section of a sample.However, the area and volume proportions are the same whenthe components are randomly distributed throughout thesample.4.1.1 Color photomicrographs of
44、 the maceral componentsof bituminous coals are available from various publications andwebsites.35. Significance and Use5.1 The volume percent of physical components of coal isused as an aid in coal seam correlation and in the character-ization of coals for their use in carbonization, gasification,li
45、quefaction, and combustion processes.5.2 This test method is for use in scientific and industrialresearch, not compliance or referee tests.6. Apparatus6.1 MicroscopeAny microscope with a mechanical stageand a vertical illuminator (that is, metallurgical or opaque-oremicroscope) may be used, provided
46、 that the lens combinationof objective and eyepiece permits resolution of objects on theorder of 1 to 2 m.Aminimum magnification of approximately400 diameters is recommended. Either a prism or a partiallyreflecting glass plate may be used in the illuminator. Oneeyepiece of the microscope should be f
47、itted with a graticule orcrosshair.6.1.1 Eyepiece DiskIf other than crosshairs are used, theeyepiece disk shall contain a Whipple graticule or one of suchdesign that four points are visible, lying at the corners of asquare covering nearly all of the field of view. The minimumeffective distance betwe
48、en the points, referred to the plane ofthe specimen, shall be 0.1 mm.6.1.2 Mechanical StageThe mechanical stage shall be ofsuch type that the specimen can be quickly advanced bydefinite fixed increments in two perpendicular directions. If anelectrically operated stage is used, increment steps in one
49、direction across the specimen may be actuated by the counterswitches.6.2 CounterCounters shall be used to count components.7. Test Specimen7.1 Prepare sample briquets in accordance with PracticeD2797.8. Procedure8.1 In accordance with present practice, maceral compo-nents counted shall be as defined in Section 3. The specificapplication will determine the degree of detail and maceralcomponents identified.8.2 When a graticule is used, count the components lyingunder each of the four points described in 6.1.1 in eachmicroscopic field. When a
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