ASTM D1857-03

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Designation: D 1857 – 03
Standard Test Method for
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Fusibility of Coal and Coke Ash
This standard is issued under the fixed designation D 1857; 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
1.1 This test method covers the observation of the tempera-
tures at which triangular pyramids (cones) prepared from coal
and coke ash attain and pass through certain defined stages of
fusing and flow when heated at a specified rate in controlled,
mildly reducing, and where desired, oxidizing atmospheres. FIG. 1 Critical Temperature Points
1.2 The test method is empirical, and strict observance of
the requirements and conditions is necessary to obtain repro-
Shrinkage or warping of the cone ignored if the tip remains
ducible temperatures and enable different laboratories to obtain
sharp. In Fig. 1, the first cone shown is an unheated one; the
concordant results.
second cone IT is a typical cone at the initial deformation stage.
1.3 The values stated in inch-pound units are to be regarded
3.1.5 softening temperature, ST—the temperature at which
as the standard.
the cone has fused down to a spherical lump in which the
1.4 This standard does not purport to address all of the
height is equal to the width at the base as shown by the third
safety concerns, if any, associated with its use. It is the
cone, ST, in Fig. 1.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Significance and Use
bility of regulatory limitations prior to use.
4.1 Design of most coal combustion and coal conversion
2. Referenced Documents equipment anticipates that the ash either remain solid or
assume some degree of fluidity, depending on the particular
2.1 ASTM Standards:
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design. Ash fusibility temperatures predict whether the ash will
D 2013 Method of Preparing Coal Samples for Analysis
perform properly in the process for which the coal was chosen.
D 3174 Test Method for Ash in the Analysis Sample of Coal
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and Coke from Coal
5. Apparatus and Materials
3. Terminology
5.1 Furnace—Any gas-fired or electric furnace conforming
to the following requirements may be used:
3.1 Definitions of Terms Specific to This Standard:
5.1.1 Capable of maintaining a uniform temperature zone in
3.1.1 The critical temperature points to be observed are as
which to heat the ash cones. This zone shall be such that the
follows, denoting the atmosphere used:
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difference in the melting point of 12.7-mm ( ⁄2-in.) pieces of
3.1.2 fluid temperature, FT—the temperature at which the
pure gold wire when mounted in place of the ash cones on the
fused mass has spread out in a nearly flat layer with a
1 cone support shall be not greater than 11°C (20°F) in a
maximum height of 1.6 mm ( ⁄16 in.) as shown by the fifth
reducing atmosphere test run.
cone, FT, in Fig. 1.
5.1.2 Capable of maintaining the desired atmosphere sur-
3.1.3 hemispherical temperature, HT—the temperature at
rounding the cones during heating. The composition of the
which the cone has fused down to a hemispherical lump at
atmosphere, reducing or oxidizing, shall be maintained within
which point the height is one half the width of the base as
the limits specified in Section 6. The desired atmosphere in the
shown by the fourth cone, HT, in Fig. 1.
gas-fired furnace surrounding the cones shall be obtained by
3.1.4 initial deformation temperature, IT—the temperature
regulation of the ratio of gas to air in the combustion mixture.
at which the first rounding of the apex of the cone occurs.
The desired atmosphere in the electric furnace shall be ob-
tained by means of gases introduced into the heating chamber.
The muffle shall be gas impervious, free from cracks, and the
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This test method is under the jurisdiction of ASTM Committee D05 on Coal
closure plug tight fitting. The gas supply tube shall be sealed to
and Coke, and is the direct responsibility of D05.21 on Methods of Analysis.
the back wall of the preheating chamber and shall not extend to
Current edition approved April 10, 2003. Published May 2003. Originally
the front of the preheating chamber against the perforated
approved 1961. Last previous edition approved 2002 as D 1857 – 87 (2002).
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Annual Book of ASTM Standards, Vol 05.06. baffle.
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D1857–03
5.1.3 Capable of regulation so that the rate of temperature thermocouple protective sheath shall be checked periodically
rise shall be 8 6 3°C (15 6 5°F)/min. for
...