ASTM D4616-95(2013)

Standard Test Method for Microscopical Analysis by Reflected Light and Determination of Mesophase in a Pitch

SIGNIFICANCE AND USE
5.1 Sometimes coal tar and petroleum pitches are heat treated thereby forming mesophase spheroids. The mesophase may be partially soluble in quinoline and cannot be estimated by the quinoline insoluble test (Test Method D2318). This test method provides for the identification, quantitative estimation, and size determination of mesophase spheroids.  
5.2 The mesophase initially forms as spheroids that may coalesce to form a variety of asymmetrical shapes. The smallest mesophase particle that can be detected with certainty at 400× or 500× magnification is 4 μm in diameter; mesophase particles sizes less than 4 μm should be ignored. If mesophase material less than 4 μm in size is of interest, then magnifications of 1000 to 1800× shall be used and the results should be appropriately identified. This method is limited to determining minor levels of mesophase, that is, ≤20 % mesophase.
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 standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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.

General Information

• Status: Historical
• Publication Date: 30-Apr-2013
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.05 - Properties of Fuels, Petroleum Coke and Carbon Material

Relations

• Replaces: ASTM D4616-95(2008) - Standard Test Method for Microscopical Analysis by Reflected Light and Determination of Mesophase in a Pitch
• Effective Date: 01-May-2013
• Replaced By: ASTM D4616-95(2018) - Standard Test Method for Microscopical Analysis by Reflected Light and Determination of Mesophase in a Pitch
• Effective Date: 01-Dec-2018

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D4616 −95 (Reapproved 2013)
Standard Test Method for
Microscopical Analysis by Reflected Light and
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Determination of Mesophase in a Pitch
This standard is issued under the fixed designation D4616; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 cenospheres—usually a minor component of coal tar
pitch. They are formed by the rapid pyrolysis of unconfined
1.1 This test method covers laboratory procedures for the
coal particles that are carried over from the coke oven to the
preparation of granular and melted samples for microscopic
tar. Microscopically, they appear like hollow spheres or seg-
analysis using reflected light to identify and estimate the
ments thereof (see Fig. 1), and are typically sized from about
amount and size of the mesophase.
10 to 500 µm. In polarized light (crossed polarizers), a
1.2 Thevaluesstatedininch-poundunitsaretoberegarded
cenospheremaybeopticallyactive.Thesizeoftheanisotropic
as standard. The values given in parentheses are mathematical
pattern or mosaic depends upon the rank of the coal carbon-
conversions to SI units that are provided for information only
ized. Cenospheres are harder than the continuous phase and
and are not considered standard.
polish in relief (see Fig. 1).
1.3 This standard does not purport to address all of the
3.1.2 coke-oven-coke—usually a minor component of coal
safety concerns, if any, associated with its use. It is the
tar pitch. It originates in carry-over from the coke oven to the
responsibility of the user of this standard to establish appro-
tar side. It differs from cenospheres only in terms of its shape
priate safety and health practices and determine the applica-
and porosity. Coke-oven-coke is angular and less porous.
bility of regulatory limitations prior to use.
3.1.3 isotropic phase—usually the predominant, and
continuous, phase. It is a complex mixture of organic aromatic
2. Referenced Documents
compounds composed mainly of carbon and hydrogen. At
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2.1 ASTM Standards:
room temperature, the isotropic phase is a glass-like solid. It is
D329Specification for Acetone
optically inactive in polarized light (see Fig. 1 and Fig. 2).
D1160TestMethodforDistillationofPetroleumProductsat
3.1.4 mesophase—an optically anisotropic liquid crystal
Reduced Pressure
carbonaceous phase that forms from the parent liquor when
D2318Test Method for Quinoline-Insoluble (QI) Content of
molecular size, shape, and distribution are favorable. In the
Tar and Pitch
early stages of its development, mesophase usually appears as
D3104Test Method for Softening Point of Pitches (Mettler
spheroids. The planar molecules are lined up equatorially as
Softening Point Method)
shown schematically in Fig. 3. This equatorial arrangement
D4296Practice for Sampling Pitch
may be distinguished in crossed polarized light. Under crossed
E11Specification forWovenWireTest Sieve Cloth andTest
polarizers, the distinctive mesophase spheroids, with their
Sieves
complex extinction patterns shown in Fig. 2, can be readily
E562Test Method for Determining Volume Fraction by
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seen.
Systematic Manual Point Count
3.1.4.1 spheroids—Atmagnificationsof400×and500×,the
3. Terminology
minimumspheroidsizewhichcanberesolvedwithconfidence
is 4 µm in diameter. At magnifications of 1000 to 1800×, the
3.1 Definitions of Terms Specific to This Standard:
minimumspheroidsizethatcanberesolvedwithconfidenceis
about 2µm in diameter. Typically, the upper size may be 100
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This test method is under the jurisdiction of ASTM Committee D02 on
µm. Mesophase spheroids are relatively soft and do not form
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
reliefstructures(seeFig.4).Quinolineinsolubleparticlesoften
SubcommitteeD02.05onPropertiesofFuels,PetroleumCokeandCarbonMaterial.
aggregate at the interface between the continuous isotropic
Current edition approved May 1, 2013. Published August 2013. Originally
approved in 1986. Last previous edition approved in 2008 as D4616–95(2008).
phase and mesophase.
DOI: 10.1520/D4616-95R13.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM AmorecompletediscussionwillbefoundinapaperbyHonda,H.,Kimura,H.,
Standards volume information, refer to the standard’s Document Summary page on andSanada,Y.,“ChangesofPleochroismandExtinctionContoursinCarbonaceous
the ASTM website. Mesophase,” Carbon, 9, 1971, pp. 695–697.
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