1、Designation: D2013/D2013M 09Standard Practice forPreparing Coal Samples for Analysis1This standard is issued under the fixed designation D2013/D2013M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of lastreapproval. 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.1. Scope1.1 This practice2covers the reduction and division of grosso
3、r divided samples, and the preparation of composite samples,up to and including the individual portions for laboratoryanalysis.1.2 Reduction and division procedures are prescribed forcoals of the following groups:1.2.1 Group A includes coals that have been cleaned in allsizes.1.2.2 Group B includes
4、all other coals. Unknown coals areto be considered under Group B.1.2.3 Group A allows smaller weight laboratory samples tobe retained than Group B. These lower weights may be used forparticular coals if they have been shown, by using theprocedures of Annex A1.2, to give a sample preparation andanaly
5、sis variance which is no more than 20 % of the totalanalysis variance.1.3 The values stated in either SI units 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. C
6、ombiningvalues from the two systems may result in non-conformancewith the standard.1.4 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 to establish appro-priate safety and health practices and
7、determine the applica-bility of regulatory limitations prior to use.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses are provided forinformation purposes only.2. Referenced Documents2.1 ASTM Standards:3D121 Terminology of Coal and CokeD2234/D2234M Prac
8、tice for Collection of a Gross Sampleof CoalD3174 Test Method for Ash in the Analysis Sample of Coaland Coke from CoalD3302 Test Method for Total Moisture in CoalD4749 Test Method for Performing the Sieve Analysis ofCoal and Designating Coal SizeE11 Specification for Woven Wire Test Sieve Cloth and
9、TestSievesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and Statistics3. Terminology3.1 Definitions of Terms Specific to This StandardNoterms are used which are specific to this practice. Many termsused in this practice may be found in
10、Terminologies D121 andE456 and in Practice E177.4. Summary of Practice4.1 Three processes of sample division and reduction arecovered as follows:4.1.1 Procedure AManual riffles are used for division ofthe sample and mechanical crushing equipment for the reduc-tion of the sample.1This practice is und
11、er the jurisdiction of ASTM Committee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.23 on Sampling.Current edition approved Nov. 1, 2009. Published January 2010. Originallyapproved in 1962. Last previous edition approved in 2007 as D2013 07. DOI:10.1520/D2013-09.2For more
12、detailed explanation of this practice see Keller, G. E., “Determinationof Quantities Needed in Coal Sample Preparation andAnalysis,” Transactions,Vol232, 1965, pp. 218-226.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
13、nual 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.4.1.2 Procedure BMechanical sample dividers are usedfor the division of th
14、e sample and mechanical crushingequipment for the reduction of the sample.4.1.3 Combined Procedure A and BThe two proceduresmay be combined at any stage.5. Significance and Use5.1 Other standards are used to collect the gross sample:Practice D2234/D2234M allows for one division of the grosssample be
15、fore crushing. The mass and top size of the gross ordivided sample collected by using these guides and practicesare usually too large for chemical or physical testing. PracticeD2013 provide instructions for reducing and dividing the grossor divided sample, by on-line or off-line processes, or both,
16、toa top size and mass suitable to the performance of testing. Anybias in the gross or divided sample before adherence to thispractice will remain in the final sample resulting from use ofthis practice. Therefore, carefully select the standard to be usedto collect the gross sample.5.2 Division and re
17、duction of a sample may occur at morethan one location. Most often, the sample is collected, reduced,and divided (one or more times) by use of a mechanicalsampling system. The remaining sample may be further di-vided on-site to facilitate transporting it to the laboratory wherefurther reduction and
18、division likely occurs before analysis.5.3 In places, this practice requires air drying the samplebefore subsequent reduction. Procedures for air drying andair-dry loss determination are provided in Test Method D3302.5.4 Most often, samples are reduced and divided to ananalysis sample. However, some
19、 tests may require a sample ofdifferent mass or top size. This procedure may be used toprovide a sample of any mass and size consist from the grossor divided sample to, and including, the analysis sample.5.5 This practice also specifies how to prepare compositesamples, if required.6. Apparatus6.1 Cr
20、ushers or GrindersJaw, cone, or rotary crusher;hammer mill; roll; or other suitable crusher to reduce thesample to pass the sieve designated in 6.4. Hard steel or chillediron plate with tamper, sledge, or hand bar may be used forpreliminary crushing of any large lumps in the sample beforefeeding int
21、o the crusher. Crushers should be designed andoperated in a manner to minimize the effect of induced aircirculation and thus the potential for drying the coal.6.1.1 Pulverizer or MillFor final reduction of laboratorysample to the 250-m (No. 60) sieve size, the followingequipment may be used:6.1.2 Ha
22、mmer MillCompletely enclosed to avoid loss ofdust or moisture.6.1.3 Porcelain-Jar Ball MillThis mill shall be approxi-mately 230 mm 9.0 in. in diameter and 250 mm 10.0 in. inheight with smooth, hard, well-rounded, flint pebbles, orequivalent, that do not increase ash content of the sample.6.1.4 Buck
23、ing Board (Chrome Steel) or Mortar (Agate orEquivalent) and PestleOnly for reducing the small fractionof sample, not passing a 250-m (No. 60) sieve after pulveri-zation.6.2 Sample Dividers:6.2.1 MechanicalA mechanical sample divider using areciprocating or rotating cutter, a rotating hopper and spou
24、t, arotating slotted cone, a reciprocating hopper and fixed cutter,bucket cutter with either bottom dump or inverting discharge,slotted belt, rotary disk divider, mechanical stopped or movingbelt sweeper, or other acceptable devices for dividing thesample. Typical mechanical sample dividers are show
25、n in Fig.1. These illustrate various designs, but other acceptable designsare available.6.2.2 RiffleA manual sample divider that splits the coalstream into a number of alternate elements. Riffle slots shall beat least three times the top size of coal being divided and havean even number of alternati
26、ng slots, in order to achieve similarmass delivered to each catch pan. Riffles shall be enclosed. Theslope of the feed chutes and riffles shall be at least 60Atypicalriffle is shown in Fig. 2.6.2.2.1 Feed ScoopA feed scoop or pan having straightsides and a width equal to the effective width of the r
27、iffle shallbe used to feed the riffle.6.2.2.2 Feed ChuteAfeed chute shall be used as shown inFig. 2. The minimum discharge opening of the feed chute shallbe the same width as the riffle slot opening.6.3 Mixing WheelOne type of a mechanical device usedfor mixing the analysis sample. In this device, t
28、he samples arein closed containers attached to the rim of a wheel at an angleof 45 with the horizontal wheel shaft. The wheel providesspace for a number of containers depending on its diameter andis turned slowly by a small motor and reduction gear. Thewheel should be rotated at a speed so that the
29、particles fallgently from top to bottom of the container, mixing the samplethoroughly. The container should be about half full and nevermore than two thirds full to obtain good mixing of the sample.6.4 SievesA set of sieves whose dimensions are in accor-dance with Specification E11, of the following
30、 sizes, withcover and receiver:No. Size4 4.75 mm8 2.36 mm20 850 m60 250 m6.5 Laboratory Sample ContainersHeavy vapor-impervious bags, properly sealed, or noncorroding cans such asthose with an airtight top, friction top, or screwtop sealed witha rubber gasket and pressure-sensitive tape for use in s
31、torageand transport of the laboratory sample. Glass containers, sealedwith rubber gaskets, may be used, but care must be taken toavoid breakage in transport.7. Precautions7.1 GeneralThe preparation of the gross or dividedsample, or the composite sample, shall be performed by, orunder the direct supe
32、rvision of, personnel knowledgeable ofproper sample handling practices. Sample preparation shouldbe checked at intervals by the methods described in Annex A1or Annex A2. It is necessary that the variance of sampledivision and analysis Sda2be not more than 20 % of the totalvariance of sampling, divis
33、ion, and analysis So2.D2013/D2013M 0927.1.1 The sample preparation operations should be per-formed in an enclosed space, roofed, cool, and free fromexcessive air movements.7.2 Number of TestsBefore preparing the gross or dividedsample, or the composite sample, consider the number andnature of the an
34、alysis and tests to be performed. A separatemoisture laboratory sample may be required, and portions maybe required for grindability and other tests. Also, a reservesample may be desired in case a check analysis or test isrequired.7.3 This practice specifies situations when air drying thesample is n
35、ecessary during sample preparation. Test MethodD3302 specifies procedures for air drying and calculation ofpercent air dry loss.7.3.1 Calculate and record air-dry loss determination eachtime air drying is performed.7.3.2 In handling, reducing, and dividing the sample, alloperations shall be done rap
36、idly and in as few operations aspossible, since moisture loss depends on several factors other(a) Reciprocating CutterFig. 1(a) shows a section of a cutter which is moved across a stream of coal. At regular intervals, the cutter movement is reversed and a sampleincrement is collected on each trip th
37、rough the coal stream.(b) Rotating CutterFig. 1(b) shows two cutters attached to a hollow, rotating shaft. Each cutter is designed to extract increments from the feed and to discharge theseinto the hollow shaft. One or more cutters may be used.(c) Rotating Hopper and SpoutFig. 1(c) shows the totalin
38、g hopper that receives the crushed sample and discharges it through a spout over one or more stationarycutters.(d) Rotating ConeA sampler developed by the British National Coal Board. Two slotted cones are locked together and rotated on a vertical shaft so that on eachrevolution the common slot oper
39、ating intercepts the falling stream of coal and collects an increment.FIG. 1 Mechanical Sample DividersD2013/D2013M 093than total moisture content, such as time required for crushing,atmospheric temperature and humidity, and type of crushingequipment.7.3.3 While awaiting preparation, the gross or di
40、videdsample shall be protected from moisture change as a result ofexposure to rain, snow, wind, and sun on contact withabsorbent materials.7.3.4 Whenever subsamples are stored or transported, thecontainers and subsample shall be weighed and equilibrated tothe new atmosphere by air drying, and the we
41、ight loss or gainshall be used in the calculation of moisture content.7.4 Whenever a distinct change of humidity occurs duringthe course of preparation of an air-dried subsample, thesubsample shall be weighed and its moisture equilibrated withthe new atmosphere, and the loss or gain in mass shall be
42、 usedin the calculation of moisture content.8. Sieve Tests8.1 The errors of sample division are sensitive to the topsize, and therefore, it is important to make a periodic sieve testof the product of the sample crusher. Sieve tests shall be madeand reported in accordance with Test Method D4749.9. Pr
43、ocedure9.1 MassThe minimum allowable mass of the sample atany stage depends on the top size, the variability of theconstituent sought, and the degree of precision desired (Table1).9.2 Reduction and Division (See Fig. 3 for flowchart):FIG. 2 Sample Divider (Riffle)TABLE 1 Preparation of Laboratory Sa
44、mpleCrush to pass at least 95% through sieveDivide to a minimumweight of, gAGroup A Group B4.75-mm (No. 4) 2000 40002.36-mm (No. 8) 500 1000850 m (No. 20) 250 500250 m ( No. 60) 50 50(100 % through)AIf a moisture sample is required, increase the quantity of No. 4 (4.75-mm) orNo. 8 (2.36-mm) sieve su
45、bsample by 500 g.D2013/D2013M 0949.2.1 It is permissible to air dry the sample before crushing.Samples may require air drying to feed properly through thereduction and dividing equipment. Sometimes there is aninterest in determining the air-dry loss value before crushing.Air dry in accordance with T
46、est Method D3302.9.2.2 In the reduction and division of gross or dividedsamples for which total moisture content is to be determined,the precautions in 7.3 and 7.4 must be followed.9.2.3 Procedure AManual Riffling:9.2.3.1 Reduce the gross or divided sample to a top size of4.75-mm (No. 4) or 2.36-mm
47、(No. 8) sieve taking precautionsin accordance with Section 7.9.2.3.2 Determine the number of passes required in theriffling operation from the total mass of the gross sample andthe minimum permissible mass in accordance with Table 1.FIG. 3 Sample Preparation FlowchartD2013/D2013M 0959.2.3.3 Divide t
48、he crushed sample by using a large riffle.Riffles properly used will reduce sample variability but cannoteliminate it. A typical enclosed riffle is shown in Fig. 2 anddescribed in 6.2.2. Pass the coal through the riffle from a feedscoop, feed bucket, or riffle pan having a lip or opening the fullwid
49、th of the riffle. When using any of the preceding containersto feed the riffle, spread the coal evenly in the container, raisethe container, and hold it with its front edge resting on top ofthe feed chute, then slowly tilt it so that the coal flows in auniform stream through the hopper straight down over thecenter of the riffle into all the slots, then into the riffle pans, onehalf of the sample being collected in each pan. Under nocircumstances shovel the sample into the riffle or dribble intothe riffle from a small-mouthed container. Do no
