1、Designation: D409/D409M 11aStandard 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 revision, the year of las
2、t 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.INTRODUCTIONThis test method is structured into the
3、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 keywords.Annex A1 contains the method to obtain and prepare coal feedstock for
4、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 homogeneity testing of the candidate HGI RMs containerized inAnnex A2.Annex A4 contai
5、ns 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 secondary HGI RMs.Annex A6 contains the method for determining the moisture conte
6、nt of the 1.18 3 0.60 mm (No.16 3 30) test sample.1. Scope1.1 This test method2covers the determination of therelative grindability or ease of pulverization of coals incomparison with coals chosen as standards. A prepared andsized sample receives a definite amount of grinding energy ina miniature pu
7、lverizer, and the size consist of the pulverizedproduct is determined by sieving. The resultant size consist isused to produce an index relative to the ease of grindingHardgrove Grindability Index (HGI).1.1.1 Some coals, such as some high-volatile bituminous,subbituminous, and lignite coals, can und
8、ergo physical changeas the natural or seam moisture is released during handling andpreparation. This change is often sufficient to alter the grind-ability characteristics that will be reported when tested in thelaboratory and could produce different indices dependent onthe conditions of drying and t
9、he moisture level of the 1.18 30.60 mm (No. 16 3 30) (see Test Method D4749) materialsused for the test. Therefore, the repeatability and reproducibil-ity cited in this test method may not apply for these high-volatile bituminous, subbituminous, and lignite coals.1.2 The values stated in either SI u
10、nits or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1This test method is un
11、der the jurisdiction of ASTM Committee D05 on Coaland Coke and is the direct responsibility of D05.07 on Physical Characteristics ofCoal.Current edition approved Dec. 1, 2011. Published January 2012. Originallyapproved in 1951. Last previous edition approved in 2011 as D409 11. DOI:10.1520/D0409_D04
12、09M-11A.2For information concerning the experimental work on which this test method isbased, see paper by Hardgrove, R. M., “Grindability of Coal,” Transactions,American Society of Mechanical Engineers, Vol 54, F.S.P., p. 37, 1932.D05.07 on Physical Characteristics on Coal is conducting ongoing inve
13、stigationsin regard to quality control during preparation, distribution, and use of standardreference materials and during preparation and testing of actual samples.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1.3 This standard do
14、es not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Sta
15、ndards:3D2013 Practice for Preparing Coal Samples for AnalysisD2234/D2234M Practice for Collection of a Gross Sampleof CoalD3302 Test Method for Total Moisture in CoalD4749 Test Method for Performing the Sieve Analysis ofCoal and Designating Coal SizeD6708 Practice for StatisticalAssessment and Impr
16、ovementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialD6883 Practice for Manual Sampling of Stationary Coalfrom Railroad Cars, Barges, Trucks, or StockpilesD7430 Practice for Mechanical Sampling of CoalE11 Specification for Woven Wire Test Sieve
17、Cloth and TestSieves3. Significance and Use3.1 This test method develops a measurement of grinding orpulverizing characteristics that can be used to evaluate theyield, or energy input, or both, required in a grinding orpulverizing process, which can impact a wide variety ofprocesses, including combu
18、stion, 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 overthe sample. The oven shall be capable of maintaining atemperature of 10 to 15 C 18 to 27 F above room tempera-ture with a max
19、imum oven temperature of 40 C 104 Funless ambient temperature is above 40 C, in which caseambient temperature shall be used. In the case of easilyoxidized coals, the temperature shall not be over 10 C 18 Fabove room temperature unless ambient temperature is above37 C 100 F in which case ambient temp
20、erature shall beused. Air changes shall be at the rate of 1 to 4 air volumes ofoven capacity per minute.4.2 Drying Pans for air-drying the 1000 g, 4.75 mm (No. 4)sampleDrying pans of sufficient size so that the sample maybe spread to a depth of not more than 25 mm 1.0 in. withsides not more than 38
21、mm 1.5 in. high. The pans shall benonreactive with coal and unaffected by the method of airdrying selected.4.3 Balance for weighing the 1000-g sample before andafter air-drying and the sieve fractions formed during stage-crushingWith a sensitivity of at least 0.5 g in 1000 g andsufficient capacity t
22、o weigh a sample with a mass of greaterthan or equal to 1000g along with the drying pan.4.4 Balance for weighing the 50-g test sample and the sievefractions formed during millingWith a sensitivity of at least10 mg and a minimum capacity of 800 g.NOTE 1A single balance meeting the specifications of 4
23、.3 and 4.4 ispermitted.4.5 Calibration WeightsThese calibration weights shallbe used periodically to monitor the response of each balanceover the working range.4.6 Sample Divider An enclosed riffle divider with feedchute as described in Practice D2013 or a rotary sampledivider, which has been proven
24、 to be free of significant bias,may be used.4.7 Standard SievesA working set of circular, standardtesting sieves, which are 203 mm 8 in. in diameter andconform to Specification E11, are required in the followingsizes, together with cover and catch pan (receiver):TABLE 1 Standard Sieves for HGI Testi
25、ngE11 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 periodically inspectedfor wear or damage. Any excessively worn or damaged sieves(for example, sieves with holes, tears, cracks;
26、etc.) must bereplaced immediately, and the HGI calibration procedure mustbe repeated after the damaged sieves are replaced (see AnnexA5). Since the HGI depends upon the sieve analysis and sincethe 75-m (No. 200) sieve is fragile, it is recommended that atleast one set of working sieves be obtained,
27、identified, and usedexclusively for HGI determinations and that only this exclusiveset of sieves be used for determining HGI.4.7.1.1 Excessive wear may be indicated by poor repeatabil-ity or by failure of quality control checks (A5.4.1.1) to agreereasonably with the initial calibration data.4.7.2 No
28、rmal wear on sieves is compensated by the use ofprimary HGI standard reference samples (HGI RMs) andproper calibration of equipment; excessive wear (such as holesor tears in the sieve cloth, and so forth) is not compensated byHGI RMs. Because excessive wear is unacceptable, inspectsieves carefully b
29、efore each test to ensure the absence ofexcessive wear. For the 75- and 600-m (No. 200 and 30)sieves, use only a soft-bristled brush (such as short-bristledcamel hair) for brushing and cleaning.4.7.2.1 It is good practice to keep a separate primary 75-m(No. 200) check sieve to be used only to check
30、the 75-m (No.200) working sieves described in 4.7.1 whenever the workingsieve becomes suspect. This check is done by running acomparative HGI test between the two 75-m (No. 200) sieves.Use of the working sieve for HGIs should be discontinued ifHGI difference between the sieves is greater than 1 HGI
31、unit.4.8 Plate Mill CrusherA laboratory plate mill capable ofreducing 4.75-mm (No. 4) sieve size coal particles with the3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer
32、 to the standards Document Summary page onthe ASTM website.D409/D409M 11a2production of a minimum of minus 0.60-mm (minus No. 30)sieve size material. The crusher plates shall be serrated andabout 100 mm 4 in. in diameter. The distance between theplates shall be adjustable, and the relative speed of
33、rotation ofthe plates shall not exceed 200 r/min.4.8.1 Evidence from HGI standard reference sample user-response forms (A5.4.4) indicates that the median value of% Yield (8.3) of the 4.75-mm (No. 4) material as 1.18 3 0.60mm (No. 16 3 30) material, regardless of the HGI level, isabout 55 %. Use this
34、 median value to gage the effectiveness/efficiency of the stage-crusher and of the stage-crushingprocess, while noting that, in some situations, the % Yield hasbeen as low as 45%.4.8.2 The most frequently used plate mill can be equippedwith “fine” or “coarse” plates. One independent study4hasfound e
35、vidence of differences in percent recovery resultingfrom use of different types of plate. In order to obtain themaximum % Yield, only the coarse plate should be used inpreparation of both HGI calibration standards and unknownsamples.4.9 Mechanical Sieving MachineThe mechanical sievingmachine shall a
36、ccept an assembly of vertically nested circularsieves of 203 mm 8 in. in diameter, together with cover andreceiver. The machine shall simulate the motions given testingsieves during hand sieving by imparting a horizontal oscilla-tory motion of approximately 28-mm 1.1-in. amplitude at arate of approx
37、imately 300 oscillations or cycles per minute(cpm). Simultaneously, the top of the oscillating assembly isstruck at a rate of approximately 150 blows per minute by amass of 1.9 kg 4.2 lb moving through a vertical distance ofapproximately 28 mm 1.1 in. under the influence of gravity.4.9.1 Whenever a
38、mechanical sieving machine other thanthe reference machine described above is used, the methodmay be shown to be equivalent by one of two methods (1) sidex side equivalency testing of the alternative machine vs. thereference machine (with both calibration and test samples thatcover the working range
39、), using the equivalency testing statis-tical technique of D6708 or (2) acceptable performance in anappropriate proficiency test program that covers the workingrange.4.10 Grindability MachineThe Hardgrove GrindabilityMachine such as is shown in Fig. 1 is required for this test.Essential tolerances a
40、nd specifications are shown in Fig. 2. Thegrindability machine includes a stationary grinding bowl ofpolished cast iron, with a circular horizontal track that holdseight polished steel balls, each 25.40 6 0.13 mm 1.000 60.005 in. in diameter. The balls are driven by an uppergrinding ring which is ro
41、tated at 20 6 1 r/min by means of theupper spindle and which, in turn, is driven by an electric motorthrough reduction gears or, in newer models, belts. Weights areadded to the driving spindle so that the total vertical force onthe balls as a result of the weights, shaft, top grinding ring, andgear
42、is equal to 29.0 6 0.2 kg 64 6 0.5 lb. The machine isequipped with a counter and automatic device, which can beproperly adjusted for stopping the machine after 60 6 0.25revolutions.4.10.1 It is good laboratory practice to have the dimensionsand the tolerances components that are subject to wear veri
43、fiedon a periodic basis.4.10.2 The position of the counter trip mechanism beforeand after the test must be used to determine the number ofrevolutions completed. With some machines, it may be neces-sary to position strategically the counter trip mechanism at thebeginning of the test to accomplish the
44、 desired number ofrevolutions (that is, during a set-up period, watch where the tripmechanism is initially, count the number of revolutions fromthe point of origin, determine where the trip mechanism is atthe end of the test, and determine if the specified 60 6 0.25revolutions are obtained. If not,
45、adjust the position of the tripmechanism at the beginning of the test until the specifiednumber of revolutions are obtained). Periodically, verify thatthe machine is operated to obtain the specified number ofrevolutions per test.5. Gross Samples5.1 Collect a gross sample of coal, representative of t
46、hematerial from which it is taken. The sample may be collected,in accordance with Practice D2234/D2234M, D6883,orD7430(or equivalent other international or national standard), andprepared in accordance with Practice D2013 (or equivalentother international or national standard) except that the sample
47、topsize shall not be reduced beyond the 4.75-mm (No. 4) sieveand the sample shall have a mass of at least 1000 g.5.2 If the topsize of the final sample product produced frommechanical sampling system is smaller than 4.75mm (No. 4),the sample does not meet the requirements of this testprocedure.6. Pr
48、eparation of Test Samples6.1 Prepare a 1.18 3 0.60 mm (No. 16 3 30) test samplefor establishing the HGI of HGI RMs (Annex A4 ), forcalibration (Annex A5), or for routine determination of HGI.6.2 When necessary, divide the quantity of 4.75-mm (No. 4)sieve size coal to not less than 1000-g lots using
49、an enclosedriffle or rotary sample divider, and air dry each sample inconformance with Test Method D3302. To calculate the% Yield (8.3), record the mass of the air-dried sample (m1).6.3 Sieve the entire amount (1000 g) of air-dried 4.75-mm(No. 4) sieve size sample in lots of no greater than 250 g for 2min 6 10 s in the mechanical sieving machine. Use a set ofnested sieves consisting of a 1.18-mm (No. 16) sieve on top ofa 0.60-mm (No. 30) sieve. Weigh and record the mass of eachsieve size.6.3.1 Include a 4.75-mm (No. 4
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