ASTM D409-02e1
(Test Method)Standard Test Method for Grindability of Coal by the Hardgrove-Machine Method
Standard Test Method for Grindability of Coal by the Hardgrove-Machine Method
SCOPE
1.1 This test method covers the determination of the relative grindability or ease of pulverization of coals in comparison with coals chosen as standards. A prepared and sized sample receives a definite amount of grinding energy in a miniature pulverizer, and the size consist of the pulverized product is determined by sieving. The resultant size consist is used to produce an index relative to the ease of grinding (Hardgrove Grindability Index (HGI)).
1.1.1 Some coals, such as some high-volatile bituminous, subbituminous, and lignite coals, can undergo physical change as the natural or seam moisture is released during handling and preparation. This change is often sufficient to alter the grindability characteristics that will be reported when tested in the laboratory and could produce different indices dependent on the conditions of drying and the moisture level of the 1.18-mm by 600-m (No. 16 No. 30) (see Test Method D 4749) materials used for the test. Therefore, the repeatability and reproducibility cited in this test method may not apply for these high-volatile bituminous, subbituminous, and lignite coals.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses may be approximate.
1.3 It is recognized that the term weight is considered equivalent to mass as used in this test method.
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:D409–02
Standard Test Method for
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Grindability of Coal by the Hardgrove-Machine Method
This standard is issued under the fixed designation D409; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
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e NOTE—Section 10.2 was editorially corrected in September 2007.
1. Scope priate safety and health practices and determine the applica-
2 bility of regulatory limitations prior to use.
1.1 This test method covers the determination of the
relative grindability or ease of pulverization of coals in
2. Referenced Documents
comparison with coals chosen as standards. A prepared and
2.1 ASTM Standards:
sized sample receives a definite amount of grinding energy in
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D2013 Method of Preparing Coal Samples for Analysis
a miniature pulverizer, and the size consist of the pulverized
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D2234 Practice for Collection of a Gross Sample of Coal
product is determined by sieving. The resultant size consist is
D4749 Test Method for Performing the Sieve Analysis of
used to produce an index relative to the ease of grinding
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Coal and Designating Coal Size
(Hardgrove Grindability Index (HGI)).
E11 Specification for Wire-Cloth Sieves for Testing Pur-
1.1.1 Some coals, such as some high-volatile bituminous,
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poses
subbituminous, and lignite coals, can undergo physical change
asthenaturalorseammoistureisreleasedduringhandlingand
3. Significance and Use
preparation. This change is often sufficient to alter the grind-
3.1 Thistestmethoddevelopsameasurementofgrindingor
ability characteristics that will be reported when tested in the
pulverizing characteristics that can be used to evaluate the
laboratory and could produce different indices dependent on
yield, or energy input, or both, required in a grinding or
theconditionsofdryingandthemoisturelevelofthe1.18-mm
pulverizing process.
by 600-µm (No. 16 3No. 30) (see Test Method D4749)
materials used for the test. Therefore, the repeatability and
4. Apparatus
reproducibilitycitedinthistestmethodmaynotapplyforthese
4.1 Air-Drying Oven—A device for passing slightly heated
high-volatile bituminous, subbituminous, and lignite coals.
air over the sample. The oven shall be capable of maintaining
1.2 The values stated in SI units are to be regarded as the
a temperature of 10 to 15°C (18 to 27°F) above room
standard.Thevaluesgiveninparenthesesmaybeapproximate.
temperature with a maximum oven temperature of 40°C
1.3 It is recognized that the term weight is considered
(104°F) unless ambient temperature is above 40°C, in which
equivalent to mass as used in this test method.
case ambient temperature shall be used. In the case of easily
1.4 This standard does not purport to address all of the
oxidized coals, the temperature shall not be over 10°C (18°F)
safety concerns, if any, associated with its use. It is the
above room temperature unless ambient temperature is above
responsibility of the user of this standard to establish appro-
37°C(100°F)inwhichcaseambienttemperatureshallbeused.
Air changes shall be at the rate of 1 to 4 air volumes of oven
capacity per minute.
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This test method is under the jurisdiction of ASTM Committee D05 on Coal
4.2 Drying Pans—Drying pans of sufficient size so that the
and Coke and is the direct responsibility of D05.07 on Physical Characteristics of
Coal.
sample may be spread to a depth of not more than 25 mm (1.0
Current edition approved April 10, 2002. Published July 2002. Originally
in.) with sides not more than 38 mm (1.5 in.) high. The pans
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published as D409–51. Last previous edition D409–97 .
2 shall be nonreactive with coal and unaffected by the method of
Forinformationconcerningtheexperimentalworkonwhichthistestmethodis
based, see paper by Hardgrove, R. M., “Grindability of Coal,” Transactions, air drying selected.
American Society of Mechanical Engineers, Vol 54, F.S.P., p. 37, 1932.
D05.07.02 on Grindability is conducting ongoing investigations in regard to
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quality control during preparation, distribution, and use of standard reference Annual Book of ASTM Standards, Vol 05.06.
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materials and during preparation and testing of actual samples. Annual Book of ASTM Standards, Vol 14.02.
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D409–02
NOTE 3—Evidence from HGI standard reference sample user-response
4.3 Balances—Two balances may be required: one with a
forms (8.4) indicates that the median value of percent recovery of the
sensitivity
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