ASTM D4616-95
(Test Method)Standard Test Method for Microscopical Analysis by Reflected Light and Determination of Mesophase in a Pitch
Standard Test Method for Microscopical Analysis by Reflected Light and Determination of Mesophase in a Pitch
SCOPE
1.1 This test method covers laboratory procedures for the preparation of granular and melted samples for microscopic analysis using reflected light to identify and estimate the amount and size of the mesophase.
1.2 The values stated in inch-pound units are to be regarded as the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 4616 – 95
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Microscopical Analysis by Reflected Light and
1
Determination of Mesophase in a Pitch
This standard is issued under the fixed designation D 4616; 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 ments thereof (see Fig. 1), and are typically sized from about
10 to 500 μm. In polarized light (crossed polarizers), a
1.1 This test method covers laboratory procedures for the
cenosphere may be optically active. The size of the anisotropic
preparation of granular and melted samples for microscopic
pattern or mosaic depends upon the rank of the coal carbon-
analysis using reflected light to identify and estimate the
ized. Cenospheres are harder than the continuous phase and
amount and size of the mesophase.
polish in relief (see Fig. 1).
1.2 The values stated in inch-pound units are to be regarded
3.1.2 coke-oven-coke—usually a minor component of coal
as the standard.
tar pitch. It originates in carry-over from the coke oven to the
1.3 This standard does not purport to address all of the
tar side. It differs from cenospheres only in terms of its shape
safety concerns, if any, associated with its use. It is the
and porosity. Coke-oven-coke is angular and less porous.
responsibility of the user of this standard to establish appro-
3.1.3 mineral matter—formed when minute particles of the
priate safety and health practices and determine the applica-
coke oven charge are carried over into the coke oven collecting
bility of regulatory limitations prior to use.
main during the charging operation. The tiny coal particles are
digested in the collecting main tar, resulting in a residue that is
2. Referenced Documents
rich in mineral matter. This mineral matter is identified under
2.1 ASTM Standards:
bright field illumination by its high reflectivity, in the case of
2
D 329 Specification for Acetone
pyrite, and its low reflectance in the case of clay, quartz, and
D 1160 Test Method for Distillation of Petroleum Products
carbonates. The association of mineral matter with insoluble
3
at Reduced Pressures
organic matter from coal aids in its identification.
D 2318 Test Method for Quinoline-Insoluble (QI) Content
4 3.1.4 refractory—usually a minor component that originates
of Tar and Pitch
from the coke oven walls, doors, and patches due to wear and
D 3104 Test Method for Softening Point of Pitches (Mettler
4 degeneration; another component is charge hole sealant. It can
Softening Point Method)
4 be recognized under the microscope through optical properties,
D 4296 Practice for Sampling Pitch
hardness, shape, and associated minerals.
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
5 3.1.5 isotropic phase—usually the predominant, and con-
poses
tinuous, phase. It is a complex mixture of organic aromatic
E 562 Practice for Determining Volume Fraction by Sys-
6 compounds composed mainly of carbon and hydrogen. At
tematic Manual Point Count
room temperature, the isotropic phase is a glass-like solid. It is
optically inactive in polarized light (see Fig. 1 and Fig. 2).
3. Terminology
3.1.6 mesophase—an optically anisotropic liquid crystal
3.1 Definitions of Terms Specific to This Standard:
carbonaceous phase that forms from the parent liquor when
3.1.1 cenospheres—usually a minor component of coal tar
molecular size, shape, and distribution is favorable. In the early
pitch. They are formed by the rapid pyrolysis of unconfined
stages of its development, mesophase usually appears as
coal particles that are carried over from the coke oven to the
spheroids. The planar molecules are lined up equatorially as
tar. Microscopically, they appear like hollow spheres or seg-
shown schematically in Fig. 3. This equatorial arrangement
may be distinguished in crossed polarized light. Under crossed
polarizers, the distinctive mesophase spheroids, with their
1
This test method is under the jurisdiction of ASTM Committee D-2 on
complex extinction patterns shown in Fig. 2, can be readily
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
7
seen.
D02.05.OF on Industrial Pitches.
Current edition approved May 15, 1995. Published July 1995. Originally
3.1.6.1 At magnifications of 4003 and 5003, the minimum
published as D 4616 – 86. Last previous edition D 4616 – 91.
spheroid size which can be resolved with confidence is 4 μm in
2
Annual Book of ASTM Standards, Vol 06.04.
3
Annual Book of ASTM Standards, Vol
...
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