ASTM D2799-99

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Designation:D 2799–99
Standard Test Method for
Microscopical Determination of Volume Percent of Physical
Components of Coal
This standard is issued under the fixed designation D 2799; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
Maceral Group Maceral
Vitrinite —
1.1 This test method covers the equipment and techniques
Liptinite or (exinite) alginite
usedfordeterminingthephysicalcompositionofacoalsample
cutinite
resinite
in terms of volume percent of the organic components and of
sporinite
mineral matter, if desired.
Inertinite fusinite
1.2 The term weight is temporarily used in this test method
inertodetrinite
macrinite
because of established trade usage. The word is used to mean
micrinite
bothforceandmassandcaremustbetakentodeterminewhich
sclerotinite
is meant in each case (the SI unit for force is newton and for semifusinite
mass, kilogram).
3.3 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.3.1 alginite, n—aliptinitemaceralthatisgenerallyspheri-
safety concerns, if any, associated with its use. It is the
cal or ovoid, frequently having a crenulated border and
responsibility of the user of this standard to establish appro-
somewhat irregular reflectance and sometimes occurring in
priate safety and health practices and determine the applica-
clusters reflecting an origin from Botryococcus algae.
bility of regulatory limitations prior to use.
3.3.1.1 Discussion—Alginite often occurs as degraded frag-
ments derived from colonial or unicellular bodies.
2. Referenced Documents
3.3.2 cutinite, n—a liptinite maceral in the form of a sheet
2.1 ASTM Standards:
reflecting its origin from leaf- or twig-covering plant cuticle,
D 121 Terminology of Coal and Coke
frequently exhibiting reticulation in planar section and a
D 2797 Practice for Preparing Coal Samples for Micro-
serrated edge in cross section.
scopic Analysis by Reflected Light
3.3.3 exinite, n—Deprecated term. Use preferred term lip-
D 2798 Test Method for Microscopical Determination of
tinite; sometimes has also been used as a synonym for
the Reflectance of Vitrinite in a Polished Specimen of
sporinite.
Coal
3.3.4 fusinite, n—an inertinite maceral distinguished princi-
D 3174 TestMethodforAshintheAnalysisSampleofCoal
pally by the preservation of some feature(s) of the plant cell
and Coke from Coal
wall structure, and with a particle size greater than 50 µm
D 3177 TestMethodforTotalSulfurintheAnalysisSample
except when it occurs as a fragment within the binder matrix;
of Coal and Coke
see also semifusinite.
3.3.5 inertinite, n—macerals that exhibit higher reflectance
3. Terminology
than other organic substances in the coal.
3.1 Definitions—For definitions of terms, refer to Terminol-
3.3.5.1 Discussion—In any coal ranked lower than anthra-
ogy D 121.
citic, inertinite reflectance commonly spans the range from
3.2 Classification—The classification of the microscopic
only slightly higher than associated vitrinite to very high
constituents into groups of similar properties in a given coal is
reflectance (often as high as Ro$ 6 %). In anthracitic rank
as follows:
coals, inertinite reflectance may be lower than that of vitrinite,
and is then recognized by its morphology and form of
anisotropy. Highly reflecting inertinite commonly exhibits
ThistestmethodisunderthejurisdictionofASTMCommitteeD-5onCoaland
Coke and is the direct responsibility of Subcommittee D05.28 on Petrographic relief on polished surface. Its name derives from the fact that
Analysis of Coal and Coke.
most varieties behave inertly in the thermoplastic deformation
Current edition approved April 10, 1999. Published July 1999. Originally
during the coking process (except in its lowest reflecting
published as D 2799 – 69 T. Last previous edition D 2799 – 98a.
Annual Book of ASTM Standards, Vol 05.05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 2799–99
manifestation). The volatile matter yield of inertinite is lower measurement of reflectance (Test Method D 2798).
than that of other macerals in the same coal. See 3.2 for the classification used by most practitioners of
this test method.
3.3.6 inertodetrinite, n—an inertinite maceral occurring as
3.3.10 macrinite, n—an inertinite maceral, generally nonan-
individual, angular, clastic fragments incorporated within the
gular, exhibiting no relict plant cell wall structure and larger
matrix of other macerals (commonly vitrinite) or minerals, and
than 10 µm.
in the size range from 2 to 50 µm.
3.3.11 micrinite, n—an inertinite maceral, generally nonan-
3.3.7 liptinite, n—macerals that exhibit lower reflectance
gular, exhibiting no relict plant cell wall structure, smaller than
than other organic substances in a coal, appearing black to dark
10 µm and most commonly occurring as particles around 1- to
gray and that fluoresce under blue to ultraviolet light in coals
5-µm diameter.
ranked high volatile bituminous and lower.
3.3.12 resinite, n—a liptinite maceral occurring as rounded,
3.3.7.1 Discussion—The fluorescence of liptinite distin-
ovoid, or rod-like bodies assuming the shape of an enclosing
guishes fine-grained liptinite from similar sized, low reflec-
cell lumen or as irregular shapes filling cracks in the coal.
tance, nonfluorescing clay minerals. Liptinite is derived prin-
3.3.13 sclerotinite, n—an inertinite maceral occurring as
cipally from lipid substances forming skins (exines) and
round or ovoid bodies, frequently containing voids, reflecting
resinous secretions or exudates of plants. Liptinite is sub-
anoriginfromfungalsclerotia;alsooccurs(especiallyinlower
classified on the basis of morphology inherited from plant
rank coals) as interlaced, stringy materials derived from fungal
structure. In coals in which vitrinite reflectance exceeds about
hyphae.
1.4 %,liptinitecanbeindistinguishablefromvitrinite.Liptinite
3.3.14 semifusinite, n—an inertinite maceral with morphol-
has the highest volatile matter yield of the macerals in a coal.
ogy like fusinite sometimes with less distinct evidence of
3.3.8 maceral, n—an organic substance in coal that is
cellular structure, but with reflectance ranging from slightly
distinguished and classified (see maceral classification)onthe
greater than that of associated vitrinite to some value interme-
basis of its optical microscopic properties.
diate to that of the brightest fusinite. The particle size is also
greater than 50 µm except when it occurs as a fragment within
3.3.8.1 Discussion—Macerals originate from plant tissues,
the binder matrix.
secretions, and exudates that have been altered by geological
3.3.14.1 Discussion—The precise reflectance boundary be-
processes and may contain up to several weight percent of
tween semifusinite and fusinite has not been universally
inorganic elements in microscopically indistinguishable form.
defined, although some practitioners place the division at
3.3.9 maceral classification, n—The systematic division of
Ro = 2.0 %; hence, semifusinite is somewhat vaguely defined
the organic substances (macerals) in coal based on their
as “fusinite with low reflectance.”
appearance in the optical microscopic.
3.3.15 sporinite, n—a liptinite maceral exhibiting various
3.3.9.1 Discussion—Although macerals may be identified
lenticular, oval, or round forms that reflect the cross-sectioning
in translucent, thin sections using criteria not defined herein,
of a flattened, hollow, ovoid body; sometimes exhibits rod-like
thistestmethoddealsonlywithidentificationandclassification
projections that are small relative to the size of the total body.
based on microscopic appearance on polished surfaces accord-
3.3.15.1 Discussion—Sporinite originated as a lipid sub-
ing to Practice D 2797. Three major maceral groups are
stance that covered, as a skin, ovoid spore or pollen grains
recognized on the basis of relative reflectance in white light,
which commonly ranged from around ten to several hundred
specifically: vitrinite—moderately reflecting (intermediate
micrometres in diameter. Sporinite often occurs as fragments
gray), liptinite—poorly reflecting (black to dark gray), and
derived from these initially ovoid bodies.
inertinite—highly reflecting (light gray to white). Each group
3.3.16 vitrinite, n—the predominant maceral in most coals
can be subdivided on the basis of other microscopically
of intermediate reflectance occurring as substantial volumes of
distinctive features such as: reflectance contrasts (relative
more or less uniformly reflecting material or a
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