1、Designation: D2799 12D2799 13Standard 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
2、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.1. Scope1.1 This test method covers the equipment and techniques used for determining the physical composition of a coal sample
3、 interms of volume percent of the organic components and of mineral matter, if desired.1.2 The term weight is temporarily used in this test method because of established trade usage. The word is used to mean bothforce and mass and care must be taken to determine which is meant in each case (the SI u
4、nit for force is newton and for mass,kilogram).1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regul
5、atorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD2797 Practice for Preparing Coal Samples for Microscopical Analysis by Reflected LightD2798 Test Method for Microscopical Determination of the Vitrinite Reflectance of CoalD3174 Test Method for
6、 Ash in the Analysis Sample of Coal and Coke from CoalD3177D4239 Test MethodsMethod for Total Sulfur in the Analysis Sample of Coal and Coke Using High-Temperature TubeFurnace Combustion (Withdrawn 2012)E177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Condu
7、cting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 DefinitionsFor definitions of terms, refer to Terminology D121.3.2 ClassificationThe classification of the microscopic constituents into groups of similar properties in a given coal is asfollows:Maceral Group
8、 MaceralVitrinite Liptinite or (exinite) alginitecutiniteresinitesporiniteInertinite fusiniteinertodetrinitemacrinitemicrinitefunginitesecretinitesemifusinite1 This test method is under the jurisdiction ofASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.28 on
9、PetrographicAnalysisof Coal and Coke.Current edition approved Sept. 1, 2012Jan. 1, 2013. Published January 2013March 2013. Originally approved in 1969. Last previous edition approved in 20112012 asD2799 11.D2799 12. DOI: 10.1520/D2799-12.10.1520/D2799-13.2 For referencedASTM standards, visit theASTM
10、 website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indi
11、cation of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be c
12、onsidered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3 Many laboratories associated with the coke-making industry use the following simplified classification for petrographicanalysis of bituminous coal:vit
13、riniteliptinite (other than resinite)resinitesemifusinitemicrinitefusinitemineral matter3.4 Definitions of Terms Specific to This Standard:3.4.1 alginite, na liptinite maceral that is generally spherical or ovoid, frequently having a crenulated border and somewhatirregular reflectance and sometimes
14、occurring in clusters reflecting an origin from Botryococcus algae.3.4.1.1 DiscussionAlginite often occurs as degraded fragments derived from colonial or unicellular bodies.3.4.2 cutinite, na liptinite maceral in the form of a sheet reflecting its origin from leaf- or twig-covering plant cuticle,fre
15、quently exhibiting reticulation in planar section and a serrated edge in cross section.3.4.3 exinite, nDeprecated term. Use preferred term liptinite; sometimes has also been used as a synonym for sporinite.3.4.4 funginite, nan inertinite maceral occurring as round or ovoid bodies, frequently contain
16、ing voids, reflecting an originfrom fungal sclerotia; also occurs (especially in lower rank coals) as interlaced, stringy materials derived from fungal hyphae.3.4.5 fusinite, nan inertinite maceral distinguished principally by the preservation of some feature(s) of the plant cell wallstructure, and
17、with a particle size greater than 50 m except when it occurs as a fragment within the binder matrix; see alsosemifusinite.3.4.6 inertinite, nmacerals that exhibit higher reflectance than other organic substances in the coal.3.4.6.1 DiscussionIn any coal ranked lower than anthracitic, inertinite refl
18、ectance commonly spans the range from only slightly higher than associatedvitrinite to very high reflectance (often as high as Romax 6 %). In anthracitic rank coals, inertinite reflectance may be lower thanthat of vitrinite, and is then recognized by its morphology and form of anisotropy. Highly ref
19、lecting inertinite commonly exhibitsrelief on polished surface. Its name derives from the fact that most varieties behave inertly in the thermoplastic deformation duringthe coking process (except in its lowest reflecting manifestation). The volatile matter yield of inertinite is lower than that of o
20、thermacerals in the same coal.3.4.7 inertodetrinite, nan inertinite maceral occurring as individual, angular, clastic fragments incorporated within the matrixof other macerals (commonly vitrinite) or minerals, and in the size range from 2 to 50 m.3.4.8 liptinite, nmacerals that exhibit lower reflect
21、ance than other organic substances in a coal, appearing black to dark grayand that fluoresce under blue to ultraviolet light in coals ranked high volatile bituminous and lower.3.4.8.1 DiscussionThe fluorescence of liptinite distinguishes fine-grained liptinite from similar sized, low reflectance, no
22、nfluorescing clay minerals.Liptinite is derived principally from lipid substances forming skins (exines) and resinous secretions or exudates of plants. Liptiniteis sub-classified on the basis of morphology inherited from plant structure. In coals in which vitrinite reflectance exceeds about1.4 %, li
23、ptinite can be indistinguishable from vitrinite. Liptinite has the highest volatile matter yield of the macerals in a coal.3.4.9 maceral, nan organic substance in coal that is distinguished and classified (see maceral classification) on the basis ofits optical microscopic properties.3.4.9.1 Discussi
24、onMacerals originate from plant tissues, secretions, and exudates that have been altered by geological processes and may contain upto several weight percent of inorganic elements in microscopically indistinguishable form.3.4.10 maceral classification, nThe systematic division of the organic substanc
25、es (macerals) in coal based on their appearancein the optical microscopic.D2799 1323.4.10.1 DiscussionAlthough macerals may be identified in translucent, thin sections using criteria not defined herein, this test method deals only withidentification and classification based on microscopic appearance
26、 on polished surfaces according to Practice D2797. Three majormaceral groups are recognized on the basis of relative reflectance in white light, specifically: vitrinitemoderately reflecting(intermediate gray), liptinitepoorly reflecting (black to dark gray), and inertinitehighly reflecting (light gr
27、ay to white). Eachgroup can be subdivided on the basis of other microscopically distinctive features such as: reflectance contrasts (relative shadesof gray); morphology, that is, shape and size (morphologic distinctions in definitions contained herein are idealized becausemorphologic appearance depe
28、nds on the initial form of the source material, its state of preservation, including granulation, and onthe orientation of the cross section presented on the polished preparation); spatial association with other substances; fluorescenceproperties (color, intensity) in blue to ultraviolet light; reli
29、ef; color tinges; internal reflections; and anisotropic properties.Microscopic criteria provide classification capability without any implication of absolute chemical composition or physicalbehavior, although some properties relative to other macerals in the same coal can be inferred broadly. Substa
30、nces classified as thesame maceral by microscopic criteria can differ chemically, physically, and behavioristically in coals of different ranks. Someproperties can be estimated by the measurement of reflectance (Test Method D2798).See 3.3 for the classification used by most practitioners of this tes
31、t method.3.4.11 macrinite, nan inertinite maceral, generally nonangular, exhibiting no relict plant cell wall structure and larger than 10m.3.4.12 micrinite, nan inertinite maceral, generally nonangular, exhibiting no relict plant cell wall structure, smaller than 10m and most commonly occurring as
32、particles around 1- to 5-m diameter.3.4.13 mineral matter, nin coal, historically considered to be the non-organic fraction composed of physically discreteparticles of minerals, such as clays, quartz, pyrite, etc., and all elements other than, carbon, hydrogen, oxygen, nitrogen, and sulfurin the org
33、anic fraction.3.4.14 resinite, na liptinite maceral occurring as rounded, ovoid, or rod-like bodies assuming the shape of an enclosing celllumen or as irregular shapes filling cracks in the coal.3.4.15 secretinite, nan inertinite maceral occurring as round, ovoid, or oblong bodies, without obvious p
34、lant structure,vesicled to non-vesicled, sometimes containing characteristic fractures, slits, or a notch.3.4.15.1 DiscussionSecretinite is considered to be derived by the oxidation of plant resin secretions or humic gels. Vesicular and non-vesicularsecretinite was formerly included in sclerotinite
35、of fungal origin. Secretinite is a common maceral in medium- and high-rankPermian and Carboniferous coals.3.4.16 semifusinite, nan inertinite maceral with morphology like fusinite sometimes with less distinct evidence of cellularstructure, but with reflectance ranging from slightly greater than that
36、 of associated vitrinite to some value intermediate to that ofthe brightest fusinite. The particle size is also greater than 50 m except when it occurs as a fragment within the binder matrix.3.4.16.1 DiscussionThe precise reflectance boundary between semifusinite and fusinite has not been universall
37、y defined, although some practitionersplace the division at Romax = 2.0 %; hence, semifusinite is somewhat vaguely defined as “fusinite with low reflectance.”3.4.17 sporinite, na liptinite maceral exhibiting various lenticular, oval, or round forms that reflect the cross-sectioning of aflattened, ho
38、llow, ovoid body; sometimes exhibits rod-like projections that are small relative to the size of the total body.3.4.17.1 DiscussionSporinite originated as a lipid substance that covered, as a skin, ovoid spore or pollen grains which commonly ranged from aroundten to several hundred micrometres in di
39、ameter. Sporinite often occurs as fragments derived from these initially ovoid bodies.3.4.18 vitrinite, nthe predominant maceral in most coals of intermediate reflectance occurring as substantial volumes of moreor less uniformly reflecting material or as a matrix enclosing particles of other maceral
40、s and mineral matter or as particles or bandsintermixed with other maceral fragments.3.4.18.1 DiscussionBecause most vitrinite is derived from the cellular, structural tissues of plants, it may exhibit relict cell structure. The reflectanceD2799 133of vitrinite is related to the rank of the coal in
41、which it is found. Reflectance increases (from around Romax = 0.3 % in ligniticcoals) in parallel with the increase in fixed carbon yield associated with increasing rank. Because many of the properties of typicalcoals reflect the properties of the dominating vitrinite, it is common practice to estim
42、ate coal properties and process behaviors bymeasuring the reflectance of a representative sampling of vitrinite in the specimen according to procedures described in TestMethod D2798.Pseudovitrinite, a certain variety of vitrinite, is differentiated by some practitioners. It exhibits slightly higher
43、reflectance thanmost of the vitrinite in the coal and is commonly slitted, with indistinct remnant cell structure and angular or jagged edges.Pseudovitrinite has been postulated to be less thermoplastic in the coking process.The term vitrinite is currently used as both a maceral and maceral group.4.
44、 Summary of Test Method4.1 The components in a representative crushed coal sample, prepared as prescribed in Practice D2797, are identified under amicroscope according to their reflectance, other optical properties, and morphology. The proportions of these components in asample are determined by obs
45、erving a statistically adequate number of points, and summing those representative of eachcomponent. Only area proportions of components are determined on a surface section of a sample. However, the area and volumeproportions are the same when the components are randomly distributed throughout the s
46、ample.4.1.1 Color photomicrographs of the maceral components of bituminous coals are available from various publications andwebsites.35. Significance and Use5.1 The volume percent of physical components of coal is used as an aid in coal seam correlation and in the characterizationof coals for their
47、use in carbonization, gasification, liquefaction, and combustion processes.5.2 This test method is for use in scientific and industrial research, not compliance or referee tests.6. Apparatus6.1 MicroscopeAny microscope with a mechanical stage and a vertical illuminator (that is, metallurgical or opa
48、que-oremicroscope) may be used, provided that the lens combination of objective and eyepiece permits resolution of objects on the orderof 1 to 2 m. A minimum magnification of approximately 400 diameters is recommended. Either a prism or a partially reflectingglass plate may be used in the illuminato
49、r. One eyepiece of the microscope should be fitted with a graticule or crosshair.6.1.1 Eyepiece DiskIf other than crosshairs are used, the eyepiece disk shall contain a Whipple graticule or one of such designthat four points are visible, lying at the corners of a square covering nearly all of the field of view. The minimum effective distancebetween the points, referred to the plane of the specimen, shall be 0.1 mm.6.1.2 Mechanical StageThe mechanical stage shall be of such type that the specimen can be quickly advanced by definitefi