1、Designation:D409/D409M09a1Designation: D409/D409M 11Standard Test Method forGrindability of Coal by the Hardgrove-Machine Method1This standard is issued under the fixed designation D409/D409M; the number immediately following the designation indicates the yearof original adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1NOTEFootnote 2 was editori
3、ally corrected in June 2010.INTRODUCTIONThis test method is structured into the following parts:The body of the test method discusses the scope, referenced documents, significance and use,apparatus, gross samples, preparation of test samples, procedure, calculation and report, precision andbias, and
4、 keywords.Annex A1 contains the method to obtain and prepare coal feedstock for potential use as HGI RMs(reference materials).Annex A2 contains the method to divide and containerize the candidate HGI RMs (candidate HGIRMs) from the feedstock prepared in Annex A1.AnnexA3 contains the method for homog
5、eneity testing of the candidate HGI RMs containerized inAnnex A2.Annex A4 contains the method for determining the Hardgrove grindability index (HGI) to beassigned to each lot of the candidate HGI RMs.AnnexA5 contains the method used to calibrate a Hardgrove grindability machine using the primaryor s
6、econdary HGI RMs.Annex A6 contains the method for determining the moisture content of the 1.18 3 0.60 mm (No.16 3 30) test sample.1. Scope1.1 This test method2covers the determination of the relative grindability or ease of pulverization of coals in comparison withcoals chosen as standards. A prepar
7、ed 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 indexrelative to the ease of grinding Hardgrove Grindability Index (HGI).1.1.1 Some co
8、als, such as some high-volatile bituminous, subbituminous, and lignite coals, can undergo physical change as thenatural or seam moisture is released during handling and preparation. This change is often sufficient to alter the grindabilitycharacteristics that will be reported when tested in the labo
9、ratory and could produce different indices dependent on the conditionsof drying and the moisture level of the 1.18 3 0.60 mm (No. 16 3 30) (see Test Method D4749) materials used for the test.Therefore, the repeatability and reproducibility cited in this test method may not apply for these high-volat
10、ile bituminous,subbituminous, and lignite coals.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from
11、 thetwo systems may result in non-conformance with 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 responsibility1This test method is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct resp
12、onsibility of D05.07 on Physical Characteristics of Coal.Current edition approved Nov. 1, 2009. Published December 2009. Originally approved in 1951. Last previous edition approved in 2009 as D40909. DOI:10.1520/D0409_D0409M-09AE01.Current edition approved April 1, 2011. Published April 2011. Origin
13、ally approved in 1951. Last previous edition approved in 2009 as D409 09a1. DOI:10.1520/D0409_D0409M-11.2For information concerning the experimental work on which this test method is based, see paper by Hardgrove, R. M., “Grindability of Coal,” Transactions, AmericanSociety of Mechanical Engineers,
14、Vol 54, F.S.P., p. 37, 1932.D05.07 on Physical Characteristics on Coal is conducting ongoing investigations in regard to quality control during preparation, distribution, and use of standard referencematerials and during preparation and testing of actual samples.1This document is not an ASTM standar
15、d and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases o
16、nly the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.of the user of this standard to establish appropriate safety and health practices an
17、d determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D2013 Practice for Preparing Coal Samples for AnalysisD2234/D2234M Practice for Collection of a Gross Sample of CoalD3302 Test Method for Total Moisture in CoalD4749 Test Method for Perform
18、ing the Sieve Analysis of Coal and Designating Coal SizeD6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purportto Measure the Same Property of a MaterialD6883 Practice for Manual Sampling of Stationary Coal from Railroad Cars, Barges, Tru
19、cks, or StockpilesD7430 Practice for Mechanical Sampling of CoalE11 Specification for Woven Wire Test Sieve Cloth and Test Sieves3. Significance and Use3.1 This test method develops a measurement of grinding or pulverizing characteristics that can be used to evaluate the yield,or energy input, or bo
20、th, required in a grinding or pulverizing process, which can impact a wide variety of processes, includingcombustion, coke-making, liquefaction, and gasification.4. Apparatus4.1 Air-Drying Oven for air-drying the 1000 g, 4.75 mm (No. 4) sampleA device for passing slightly heated air over thesample.
21、The oven shall be capable of maintaining a temperature of 10 to 15 C 18 to 27 F above room temperature with amaximum oven temperature of 40 C 104 F unless ambient temperature is above 40 C, in which case ambient temperature shallbe used. In the case of easily oxidized coals, the temperature shall no
22、t be over 10 C 18 F above room temperature unlessambient temperature is above 37 C 100 F in which case ambient temperature shall be used. Air changes shall be at the rate of1 to 4 air volumes of oven capacity per minute.4.2 Drying Pans for air-drying the 1000 g, 4.75 mm (No. 4) sampleDrying pans of
23、sufficient size so that the sample maybe spread to a depth of not more than 25 mm 1.0 in. with sides not more than 38 mm 1.5 in. high. The pans shall be nonreactivewith coal and unaffected by the method of air drying selected.4.3 Balance for weighing the 1000-g sample before and after air-drying and
24、 the sieve fractions formed during stage-crushingWith a sensitivity of at least 0.5 g in 1000 g and sufficient capacity to weigh a sample with a mass of greater than orequal to 1000g along with the drying pan.4.4 Balance for weighing the 50-g test sample and the sieve fractions formed during milling
25、With a sensitivity of at least10 mg and a minimum capacity of 800 g.NOTE 1A single balance meeting the specifications of 4.3 and 4.4 is permitted.4.5 Calibration WeightsThese calibration weights shall be used periodically to monitor the response of each balance over theworking range.4.6 Sample Divid
26、er An enclosed riffle divider with feed chute as described in Practice D2013 or a rotary sample divider,which has been proven to be free of significant bias, may be used.4.7 Standard SievesA working set of circular, standard testing sieves, which are 203 mm 8 in. in diameter and conform toSpecificat
27、ion E11, are required in the following sizes, together with cover and catch pan (receiver):TABLE 1 Standard Sieves for HGI TestingE11 Specification U.S.A. Standard Sieve Series Designation16.0 mm58 in.4.75 mm No. 42.36 mm No. 81.18 mm No. 16600 m No. 3075 m No. 2004.7.1 These working sieves must be
28、periodically inspected for wear or damage. Any excessively worn or damaged sieves (forexample, sieves with holes, tears, cracks; etc.) must be replaced immediately, and the HGI calibration procedure must be repeatedafter the damaged sieves are replaced (see Annex A5). Since the HGI depends upon the
29、sieve analysis and since the 75-m (No.200) sieve is fragile, it is recommended that at least one set of working sieves be obtained, identified, and used exclusively for HGIdeterminations and that only this exclusive set of sieves be used for determining HGI.3For referencedASTM standards, visit theAS
30、TM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D409/D409M 1124.7.1.1 Excessive wear may be indicated by poor repeatability or by failure of quality con
31、trol checks (A5.4.1.1) to agreereasonably with the initial calibration data.4.7.2 Normal wear on sieves is compensated by the use of primary HGI standard reference samples (HGI RMs) and propercalibration of equipment; excessive wear (such as holes or tears in the sieve cloth, and so forth) is not co
32、mpensated by HGI RMs.Because excessive wear is unacceptable, inspect sieves carefully before each test to ensure the absence of excessive wear. For the75- and 600-m (No. 200 and 30) sieves, use only a soft-bristled brush (such as short-bristled camel hair) for brushing andcleaning.4.7.2.1 It is good
33、 practice to keep a separate primary 75-m (No. 200) check sieve to be used only to check the 75-m (No.200) working sieves described in 4.7.1 whenever the working sieve becomes suspect. This check is done by running a comparativeHGI test between the two 75-m (No. 200) sieves. Use of the working sieve
34、 for HGIs should be discontinued if HGI differencebetween the sieves is greater than 1 HGI unit.4.8 Plate Mill CrusherA laboratory plate mill capable of reducing 4.75-mm (No. 4) sieve size coal particles with theproduction of a minimum of minus 0.60-mm (minus No. 30) sieve size material. The crusher
35、 plates shall be serrated and about100 mm 4 in. in diameter. The distance between the plates shall be adjustable, and the relative speed of rotation of the plates shallnot exceed 200 r/min.4.8.1 Evidence from HGI standard reference sample user-response forms (A5.4.4) indicates that the median value
36、of % Yield(8.3) of the 4.75-mm (No. 4) material as 1.18 3 0.60 mm (No. 16 3 30) material, regardless of the HGI level, is about 55 %. Usethis median value to gage the effectiveness/efficiency of the stage-crusher and of the stage-crushing process, while noting that, insome situations, the % Yield ha
37、s been as low as 45%.4.8.2 The most frequently used plate mill can be equipped with “fine” or “coarse” plates. One independent study4has foundevidence of differences in percent recovery resulting from use of different types of plate. In order to obtain the maximum % Yield,only the coarse plate shoul
38、d be used in preparation of both HGI calibration standards and unknown samples.4.9 Mechanical Sieving MachineThe mechanical sieving machine shall accept an assembly of vertically nested circular sievesof 203 mm 8 in. in diameter, together with cover and receiver. The machine shall simulate the motio
39、ns given testing sieves duringhand sieving by imparting a horizontal oscillatory motion of approximately 28-mm 1.1-in. amplitude at a rate of approximately300 oscillations or cycles per minute (cpm). Simultaneously, the top of the oscillating assembly is struck at a rate of approximately150 blows pe
40、r minute by a mass of 1.9 kg 4.2 lb moving through a vertical distance of approximately 28 mm 1.1 in. under theinfluence of gravity.4.9.1 Whenever a mechanical sieving machine other than the reference machine described above is used, the method may beshown to be equivalent by one of two methods (1)
41、side x side equivalency testing of the alternative machine vs. the referencemachine (with both calibration and test samples that cover the working range), using the equivalency testing statistical techniqueof D6708 or (2) acceptable performance in an appropriate proficiency test program that covers
42、the working range.4.10 Grindability MachineThe Hardgrove Grindability Machine such as is shown in Fig. 1 is required for this test. Essentialtolerances and specifications are shown in Fig. 2. The grindability machine includes a stationary grinding bowl of polished castiron, with a circular horizonta
43、l track that holds eight polished steel balls, each 25.40 6 0.13 mm 1.000 6 0.005 in. in diameter.The balls are driven by an upper grinding ring which is rotated at 20 6 1 r/min by means of the upper spindle and which, in turn,is driven by an electric motor through reduction gears or, in newer model
44、s, belts. Weights are added to the driving spindle so thatthe total vertical force on the balls as a result of the weights, shaft, top grinding ring, and gear is equal to 29.0 6 0.2 kg 64 60.5 lb. The machine is equipped with a counter and automatic device, which can be properly adjusted for stoppin
45、g the machineafter 60 6 0.25 revolutions.4.10.1 It is good laboratory practice to have the dimensions and the tolerances components that are subject to wear verified ona periodic basis.4.10.2 The position of the counter trip mechanism before and after the test must be used to determine the number of
46、 revolutionscompleted. With some machines, it may be necessary to position strategically the counter trip mechanism at the beginning of thetest to accomplish the desired number of revolutions (that is, during a set-up period, watch where the trip mechanism is initially,count the number of revolution
47、s from the point of origin, determine where the trip mechanism is at the end of the test, anddetermine if the specified 60 6 0.25 revolutions are obtained. If not, adjust the position of the trip mechanism at the beginningof the test until the specified number of revolutions are obtained). Periodica
48、lly, verify that the machine is operated to obtain thespecified number of revolutions per test.5. Gross Samples5.1 Collect a gross sample of coal, representative of the material from which it is taken. The sample may be collected, inaccordance with Practice D2234/D2234M, D6883, or D7430 (or equivale
49、nt other international or national standard), and preparedin accordance with Practice D2013 (or equivalent other international or national standard) except that the sample topsize shall notbe reduced beyond the 4.75-mm (No. 4) sieve and the sample shall have a mass of at least 1000 g.5.2 If the topsize of the final sample product produced from mechanical sampling system is smaller than 4.75mm (No. 4), thesample does not meet the requirements of this test procedure.4D05.07 Minutes, J. Gardner, Georgia Power and G
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