1、Designation: D 2799 05aStandard Test Method forMicroscopical Determination of the Maceral Composition ofCoal1This standard is issued under the fixed designation D 2799; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st 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 test method covers the equipment and techniquesused for determining the physical composition of a coal samplein te
3、rms 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
4、force 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 l
5、imitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 121 Terminology of Coal and CokeD 2797 Practice for Preparing Coal Samples for Micro-scopic Analysis by Reflected LightD 2798 Test Method for Microscopical Determination ofthe Vitrinite Reflectance of CoalD 3174 Test Method forAsh
6、in theAnalysis Sample of Coaland Coke from CoalD 3177 Test Method for Total Sulfur in theAnalysis Sampleof Coal and Coke3. Terminology3.1 DefinitionsFor definitions of terms, refer to Terminol-ogy D 121.3.2 ClassificationThe classification of the microscopicconstituents into groups of similar proper
7、ties in a given coal isas follows:Maceral Group MaceralVitrinite Liptinite or (exinite) alginitecutiniteresinitesporiniteInertinite fusiniteinertodetrinitemacrinitemicrinitefunginitesecretinitesemifusinite3.3 Definitions of Terms Specific to This Standard:3.3.1 alginite, na liptinite maceral that is
8、 generally spheri-cal or ovoid, frequently having a crenulated border andsomewhat irregular reflectance and sometimes occurring inclusters reflecting an origin from Botryococcus algae.3.3.1.1 DiscussionAlginite often occurs as degraded frag-ments derived from colonial or unicellular bodies.3.3.2 cut
9、inite, 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 cross section.3.3.3 exinite, nDeprecated term. Use preferred term lip-tinite; sometimes has also been used as a
10、 synonym forsporinite.3.3.4 funginite, nan inertinite maceral occurring as roundor ovoid bodies, frequently containing voids, reflecting anorigin from fungal sclerotia; also occurs (especially in lowerrank coals) as interlaced, stringy materials derived from fungalhyphae.3.3.5 fusinite, nan inertini
11、te maceral distinguished princi-pally by the preservation of some feature(s) of the plant cellwall structure, and with a particle size greater than 50 mexcept when it occurs as a fragment within the binder matrix;see also semifusinite.3.3.6 inertinite, nmacerals that exhibit higher reflectancethan o
12、ther organic substances in the coal.3.3.6.1 DiscussionIn any coal ranked lower than anthra-citic, 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
13、 be lower than that of vitrinite,and is then recognized by its morphology and form of1This 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. 15, 2
14、005. Published October 2005. Originallyapproved in 1969. Last previous edition approved in 2005 as D 2799 05.2For 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 sta
15、ndards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.anisotropy. Highly reflecting inertinite commonly exhibitsrelief on polished surface. Its name derives from the fact thatmost varieties b
16、ehave inertly in the thermoplastic deformationduring the coking process (except in its lowest reflectingmanifestation). The volatile matter yield of inertinite is lowerthan that of other macerals in the same coal.3.3.7 inertodetrinite, nan inertinite maceral occurring asindividual, angular, clastic
17、fragments incorporated within thematrix of other macerals (commonly vitrinite) or minerals, andin the size range from 2 to 50 m.3.3.8 liptinite, nmacerals that exhibit lower reflectancethan other organic substances in a coal, appearing black to darkgray and that fluoresce under blue to ultraviolet l
18、ight in coalsranked high volatile bituminous and lower.3.3.8.1 DiscussionThe fluorescence of liptinite distin-guishes fine-grained liptinite from similar sized, low reflec-tance, nonfluorescing clay minerals. Liptinite is derived prin-cipally from lipid substances forming skins (exines) andresinous
19、secretions or exudates of plants. Liptinite is sub-classified on the basis of morphology inherited from plantstructure. In coals in which vitrinite reflectance exceeds about1.4 %, liptinite can be indistinguishable from vitrinite. Liptinitehas the highest volatile matter yield of the macerals in a c
20、oal.3.3.9 maceral, nan organic substance in coal that isdistinguished and classified (see maceral classification)onthebasis of its optical microscopic properties.3.3.9.1 DiscussionMacerals originate from plant tissues,secretions, and exudates that have been altered by geologicalprocesses and may con
21、tain up to several weight percent ofinorganic elements in microscopically indistinguishable form.3.3.10 maceral classification, nThe systematic division ofthe organic substances (macerals) in coal based on theirappearance in the optical microscopic.3.3.10.1 DiscussionAlthough macerals may be identif
22、iedin translucent, thin sections using criteria not defined herein,this test method deals only with identification and classificationbased on microscopic appearance on polished surfaces accord-ing to Practice D 2797. Three major maceral groups arerecognized on the basis of relative reflectance in wh
23、ite light,specifically: vitrinitemoderately reflecting (intermediategray), liptinitepoorly reflecting (black to dark gray), andinertinitehighly reflecting (light gray to white). Each groupcan be subdivided on the basis of other microscopicallydistinctive features such as: reflectance contrasts (rela
24、tiveshades of gray); morphology, that is, shape and size (morpho-logic distinctions in definitions contained herein are idealizedbecause morphologic appearance depends on the initial form ofthe source material, its state of preservation, including granu-lation, and on the orientation of the cross se
25、ction presented onthe polished preparation); spatial association with other sub-stances; fluorescence properties (color, intensity) in blue toultraviolet light; relief; color tinges; internal reflections; andanisotropic properties.Microscopic criteria provide classification capability with-out any i
26、mplication of absolute chemical composition orphysical behavior, although some properties relative to othermacerals in the same coal can be inferred broadly. Substancesclassified as the same maceral by microscopic criteria candiffer chemically, physically, and behavioristically in coals ofdifferent
27、ranks. Some properties can be estimated by themeasurement of reflectance (Test Method D 2798).See 3.2 for the classification used by most practitioners ofthis test method.3.3.11 macrinite, nan inertinite maceral, generally nonan-gular, exhibiting no relict plant cell wall structure and largerthan 10
28、 m.3.3.12 micrinite, nan inertinite maceral, generally nonan-gular, exhibiting no relict plant cell wall structure, smaller than10 m and most commonly occurring as particles around 1- to5-m diameter.3.3.13 resinite, na liptinite maceral occurring as rounded,ovoid, or rod-like bodies assuming the sha
29、pe of an enclosingcell lumen or as irregular shapes filling cracks in the coal.3.3.14 secretinite, nan inertinite maceral occurring asround, ovoid, or oblong bodies, without obvious plant struc-ture, vesicled to non-vesicled, sometimes containing character-istic fractures, slits, or a notch.3.3.14.1
30、 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 origin. Secretinite is a commonmaceral in medium- and high-rank Permian and Carboniferouscoals.3.3.15 semi
31、fusinite, nan inertinite maceral with morphol-ogy like fusinite sometimes with less distinct evidence ofcellular structure, but with reflectance ranging from slightlygreater than that of associated vitrinite to some value interme-diate to that of the brightest fusinite. The particle size is alsogrea
32、ter than 50 m except when it occurs as a fragment withinthe binder matrix.3.3.15.1 DiscussionThe precise reflectance boundary be-tween semifusinite and fusinite has not been universallydefined, although some practitioners place the division atRo = 2.0 %; hence, semifusinite is somewhat vaguely defin
33、edas “fusinite with low reflectance.”3.3.16 sporinite, na liptinite maceral exhibiting variouslenticular, oval, or round forms that reflect the cross-sectioningof a flattened, hollow, ovoid body; sometimes exhibits rod-likeprojections that are small relative to the size of the total body.3.3.16.1 Di
34、scussionSporinite 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. Sporinite often occurs as fragmentsderived from these initially ovoid bodies.3.3.17 vitrinite, nthe predominant mac
35、eral 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 matter or asparticles or bands intermixed with other maceral fragments.3.3.17.1 DiscussionBecause most vitrinite
36、 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. Reflectance increases(from around Ro = 0.3 % in lignitic coals) in parallel with theincrease in fixed carbon yield ass
37、ociated with increasing rank.Because many of the properties of typical coals reflect theD 2799 05a2properties of the dominating vitrinite, it is common practice toestimate coal properties and process behaviors by measuringthe reflectance of a representative sampling of vitrinite in thespecimen accor
38、ding to procedures described in Test MethodD 2798.Pseudovitrinite, a certain variety of vitrinite, is differentiatedby some practitioners. It exhibits slightly higher reflectancethan most of the vitrinite in the coal and is commonly slitted,with indistinct remnant cell structure and angular or jagge
39、dedges. 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. The subcommittee is actively working ondefining subcategories of the maceral group-vitrinite.4. Summary of Test Method4.1 The component
40、s in a representative crushed coalsample, prepared as prescribed in Practice D 2797, 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 number o
41、f 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.5. Significance and Use5.1 The volume
42、 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,liquefaction, and combustion processes.5.2 This test method is for use in scientific and industrialresearch, not compliance or referee
43、tests.6. Apparatus6.1 MicroscopeAny microscope with a mechanical stageand a vertical illuminator (that is, metallurgical or opaque-oremicroscope) may be used, provided that the lens combinationof objective and eyepiece permits resolution of objects on theorder of 1 to 2 m.Aminimum magnification of a
44、pproximately400 diameters is recommended. Either a prism or a partiallyreflecting glass plate may be used in the illuminator. Oneeyepiece of the microscope should be fitted with a graticule orcrosshair.6.1.1 Eyepiece DiskIf other than crosshairs are used, theeyepiece disk shall contain a Whipple gra
45、ticule 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 between the points, referred to the plane ofthe specimen, shall be 0.1 mm.6.1.2 Mechanical StageThe mechanical stage shall be ofsuch type
46、that the specimen can be quickly advanced bydefinite fixed increments in two perpendicular directions. If anelectrically operated stage is used, increment steps in onedirection across the specimen may be actuated by the counterswitches.6.2 CounterThe counter shall be capable of recordingcounts for a
47、t least six components.7. Test Specimen7.1 Prepare sample briquets in accordance with PracticeD 2797.8. Procedure8.1 In accordance with present practice, maceral compo-nents counted shall be as defined in Section 3.NOTE 1The specific application will determine the degree of detailand maceral compone
48、nts 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 crosshair disk is used, count thecomponent lying under the intersection of the crosshairs.8.3 Advance the specimen in steps of 1.0 mm when agraticu
49、le is used and 0.5 mm when a crosshair is used, until thedesired length of the specimen in that direction has beencovered. Then advance the specimen one similar step at rightangles and repeat the first procedure in reverse. Do not countany of the field points that fall on the briquet binder. Generally,only organic components are counted. Pyrite and other visiblemineral matter may be counted.8.4 A better approximation of the total mineral content maybe calculated from ash and sulfur contents determined inaccordance with Test Methods D 3174 a
