1、Designation: D 441 07Standard Test Method ofTumbler Test for Coal1This standard is issued under the fixed designation D 441; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicat
2、es the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the relativefriability of a particular size of sized coal. It affords a means ofmeasuring the liability of coal to bre
3、ak into smaller pieceswhen subjected to repeated handling at the mine or subse-quently, by the distributor or by the consumer. This test methodis serviceable for ascertaining the similarity of coals in respectto friability rather than for determining values within narrowlimits to emphasize their dis
4、similarity. This test method alsomay serve to indicate the relative extent to which sized coalswill suffer size degradation in certain mechanical feed devices.This test method may be used for differentiating betweencertain ranks and grades of coal, and therefore the test methodis of service for coal
5、 classification purposes.1.2 The values stated in inch-pound units shall be regardedas the standard. Mass may be expressed in metric values.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard t
6、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2234/D 2234M Practice for Collection of a Gross Sampleof CoalD 4749 Test Method for Performing the Sieve Analysis ofCoal and Desig
7、nating Coal SizeE11 Specification for Wire Cloth and Sieves for TestingPurposes3. Significance and Use3.1 This test method is a measure of the resistance of thecoal to breakage upon impact and abrasion as the coal rubstogether and against the walls of the transportation vehicle.4. Apparatus4.1 Porce
8、lain Jar Tumbler, consisting of a cylindrical por-celain jar of uniform dimensions, 714 in. (184 mm) in diameterand 714 in. in depth, inside measurements, such as is used forpulverizing coal samples for analysis. The jar shall be fittedinside an iron frame with lifting shelves constructed as shownin
9、 Fig. 1. The two rings, a, shall be 718 in. (181 mm) in outsidediameter and shall be made of34-by18-in. (19- by 3-mm) iron.The three ledges or shelves, b,612 by34 by18 in. (165 by 19by 3 mm), shall be attached radially to the rings by means ofsmall brackets, c, the ends of the shelves being flush wi
10、th theouter edges of the rings. The shelves shall be attached so thatthere will be58-in. (15.9-mm) clearance between their outeredge and the outside of the ring. Rivets, not bolts, shall be usedin constructing the frame. As the jars available commerciallyare not of absolutely uniform size, the measu
11、rements of theframe may be slightly varied to suit individual cases.The frameshall be fixed inside the jar by means of wedges between therings and the inside wall of the jar so that its axis shall coincideas nearly as possible with the axis of the jar, and so that theframe will rotate with the jar.
12、The jar shall be closed by a set-inporcelain lid resting upon a heavy rubber gasket and sealedtightly according to the customary procedure with such jars,that is, by means of a bolt working against the lid. The boltshall be set in a crossbar, the ends of which shall be held by ametal strip which fit
13、s around the body of the jar. For tumbling,the jar shall be laid in a horizontal position in a suitable supportor rack and rotated about its cylindrical axis at the rate of 40rpm. The assembled apparatus is illustrated in Fig. 2.4.2 Optional Iron Jar TumblerAn iron jar may be substi-tuted for the po
14、rcelain jar specified in 4.1, provided it hasapproximately the same internal dimensions, namely, 714 in. indiameter by 714 in. in depth. A jar constructed of cast iron isrecommended, and the interior machined to the requiredinternal dimensions. For making it sufficiently light for lifting,the jar ma
15、y have a wall thickness of not less than14 in. (6.35mm), except at each end. It is recommended that the lid, rubbergasket, and the metal strip that passes from the bottom up theoutside of the jar to serve in holding in place the crossbar abovethe lid, be similar in design with those for the porcelai
16、n jar. Thewall of the iron jar for a distance of approximately 1 in. (25.4mm) from the top shall have a thickness of at least12 in. (12.7mm) to correspond with that of the porcelain jar; and in order1This method is under the jurisdiction of ASTM Committee D05 on Coal andCoke and is the direct respon
17、sibility of Subcommittee D05.07 on PhysicalCharacteristics of Coal.Current edition approved Oct. 1, 2007. Published October 2007. Originallyapproved in 1937. Last previous edition approved in 2002 as D 441 86 (2002).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM
18、 Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.that the metal strip may fit e
19、venly, the lower inch of the wallshould also have a thickness of not less than12 in.4.3 SievesFor sizing the sample for test, square-holesieves having 1.50- and 1.06-in. (38.1- and 26.9-mm) actualopenings between the wires shall be used. These sieves may befitted into frames, 12 by 30 in. (305 by 76
20、2 mm) or larger. Forsieving the coal after tumbling, square-hole sieves having1.06-, 0.750-, 0.530-, 0.375-, 0.0469-, and 0.0117-in. (26.9-,19.0-, 13.5-, 9.51-, 1.19-, and 0.297-mm) actual openingsbetween the wires shall be used. For this purpose, round,metal-framed sieves 8 in. (200 mm) in diameter
21、 are suitable.The sieves shall conform to Specification E11.4.4 BalanceThe balance used for weighing the sampleshall be sensitive to 1 g.5. Sampling5.1 Collection of Gross SampleCollect the gross sampleof coal in accordance with Practice D 2234/D 2234M and TestMethod D 4749.5.2 Preparation of Sample
22、:5.2.1 Make a preliminary sieving of a representative por-tion, approximately 100 lbs (45 kg), of the gross sample, usingsquare-hole sieves with 1.06- and 1.50-in. (26.9- and 38.1-mm)openings. If this preliminary sieving indicates that the pieces ofcoal are mostly smaller than 1.50 in., sieve succes
23、sive repre-sentative portions of the gross sample until at least 25 lbs (11kg) of the 1.06- to 1.50-in. size are obtained. If most of thepieces obtained by the preliminary sieving are larger than 1.50in., conduct sieving of representative portions of the grosssample until at least 50 lbs (23 kg) of
24、the sieved materialremaining on the 1.06-in. sieve are available. Then break thepieces so obtained that are larger than 1.50 in. with a hammeruntil they pass the 1.50-in. sieve, avoiding as much as possiblethe production of pieces smaller than 1.06 in. Should thecombined weights of the 1.06- to 1.50
25、-in. size, obtained bysieving before and after hammer breakage of the larger pieces,be less than the required 25 lbs, augment the amount by furthersieving and breakage of additional representative portions, orthe remainder of the gross sample, taking care to discard allpieces in which noticeable cra
26、cks have developed by hammerbreakage. Take care also to provide pieces covering the wholerange of the 1.06- to 1.50-in. size in both the 25-lbs compositesample, and in each 1000-g sample taken for test as in Section5. This may be accomplished by the use of a 1.25-in.(31.5-mm) sieve to see that appro
27、ximately half of the weight ofthe pieces comprising these samples will be between 1.06 and1.25 in. and half between 1.25 and 1.50 in.5.2.2 Mix thoroughly the total quantity of the 1.06- to1.50-in. size and then resieve it to pass the 1.50-in. sieve andbe retained on the 1.06-in. sieve. Place only a
28、thin layer of coalon the sieve so as to allow the pieces to be in direct contactwith the sieve openings. Upend by hand individual pieces ofcoal not passing readily through the sieve to determine whetherin any position they pass the sieve.6. Procedure6.1 Weigh approximately 1000 g of the coal sample,
29、 pre-pared in accordance with 5.1, and place it in the jar. Rotate thejarfor1hinthetumbler test machine at 40 6 1 rpm. Tostandardize the time of tumbling, use a revolution counter,either periodically or as permanent accessory equipment to themachine, to ensure that the total number of revolutions du
30、ringa test is approximately 2400. After tumbling, thoroughly gradethe coal as to size upon the sieves designated in 4.3. Carry outthe sieving in such small increments as to permit satisfactorycontact between the individual pieces of coal and the sieve. Onthe two larger sieves, 1.06- and 0.750-in. (2
31、6.9- and 19.0-mm)Metric Equivalentsin.185834 612 718(mm) (3.18) (15.9) (19.0) (165) (181)FIG. 1 Steel Frame Used in Jar MillNOTE 1On the bench are shown typical jar mills in which thethree-vane iron frames are fitted, together with a set of 8-in. (200 mm)diameter sieves and a 1000-g charge of 1.06-
32、to 1.50-in. (26.5 to 38.1-mm)size coal. The jar to the left is one of the regular porcelain jars, and thatto the right an optional iron jar.FIG. 2 Tumbler Test ApparatusD441072upend by hand individual pieces of coal not readily passingthrough the sieves to determine whether in any position theypass
33、the sieve.6.2 Sieving may be carried out either by hand or mechani-cally, though the former method is preferable.6.3 Make at least four single-jar tests, and, provided suffi-cient sample is available, it is recommended that two or morefour-jar tests be made. When only four single-jar tests aremade,
34、sieve the contents of each jar separately in order to besure that there is satisfactory agreement between the resultsobtained. When two or more four-jar tests are made, thecontents of the four jars from each set may be mixed and sievedtogether. Make the weighings to the nearest 1 g.7. Calculations7.
35、1 The product of the weight percent of the initial 1.06- by1.50-in. sample and its average sieve opening in inches isnormalized to equal 100 % (see Table 1). This is S.7.2 After testing, the resultant weight percent distribution isdetermined. The products of the various normalized averagesize openin
36、g of the size fractions and the respective weightpercent are determined. These products are summed. This sumis s (see Table 1).7.3 Friability is calculated as 100 3 (S s)/S and is re-ported to the nearest 0.5 %.7.4 Dust index is numerically equal to the percent of No.50 (USA Standard) material produ
37、ced during the tumbler testand is reported as the nearest whole number index (see Table1).8. Report8.1 Report friability in percent to the nearest 0.5 %. This isthe percentage reduction in average size of the coal during thetumbler test.NOTE 1Anumerical example of the method of calculating friabilit
38、y isgiven in Table 1, where the average of the openings of the retaining andpassing sieves is expressed in inches (millimetres) to the nearest 0.001 in.(0.025 mm). The data shown are for a typical coal of medium friability. Itis from the average of the sieve openings that the approximate relative si
39、zefactors, shown as column (3) are derived. In the column to the extremeright, S represents the average size of the coal pieces before tumbling, ands the average size of the tumbled coal, the value for S being arbitrarilychosen as 100 times its corresponding size factor.9. Precision and Bias9.1 Data
40、 for repeatability and reproducibility do not existbut are being determined.9.2 This is an empirical test method and no statement of biasis possible.10. Keywords10.1 breakage; coal; coal handling; friability; size stability;tumblerTABLE 1 Sieve Analysis of Coal Using Square-Hole SievesNOTE 1Friabili
41、ty, % = 100(S s)/S = 100(100 68.56)/100 = 31.4. To be reported as: Friability, 31.5 %.Retained On PassingWeight,%(1)Average ofSieve OpeningsProduct of(1) 3 (2)InchesNormalizingFactor(2)SAMPLE1.06 in. (26.5 mm) 1.50 in. (38.1 mm) 100.0 1.280 1 100.00 = STUMBLED COAL1.06 in. (26.5 mm) 1.50 in. (38.1 m
42、m) 46.2 1.280 1 46.20.750 in. (19.0 mm) 1.06 in. (26.5 mm) 26.9 0.905 0.7 18.830.530 in. (13.2 mm) 0.750 in. (19.0 mm) 4.0 0.640 0.5 2.000.375 in. (9.5 mm) 0.530 in. (13.2 mm) 1.6 0.452 0.35 0.560.0469 in. (No. 16) 0.375 in. (9.5 mm) 5.5 0.211 0.16 0.8800.0117 in. (No. 50) 0.0469 in. (No. 16) 0.5 0.
43、029 0.023 0.0120.0117 in. (No. 50)A15.3B0.006 0.005 0.077Total (Sum of products (1) 3 (3) for tumbled coal) 68.56 =sAIncluding loss, not to exceed 0.5 %.BThe percentage of “fines and dust” passing the 0.0117-in. (No. 50) sieve represents the proportion of the breakage due to attrition or abrasion ra
44、ther than to shattering,and may be reported as “dust index” to the nearest whole percent to indicate the relative dust-producing properties of coals when subjected to severe handling. Henceboth the friability in percent and the “dust index” may be reported as follows: Friability, % = 31.5; with dust
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