1、Designation: D2013/D2013M 11Standard 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.2. Referenced Documents2.1 ASTM Standards:3D121 Terminology of Coal and CokeD2234/D2234M Practice for Collection of a Gross Sampleof CoalD3174 Test Method for Ash in the Analysis Sample of Coaland Coke from CoalD3302 Test Method for
8、 Total Moisture in CoalD4749 Test Method for Performing the Sieve Analysis ofCoal and Designating Coal SizeE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and Statistics3. Te
9、rminology3.1 Definitions of Terms Specific to This StandardNoterms are used which are specific to this practice. Many termsused in this practice may be found in Terminologies D121 andE456 and in Practice E177.4. Summary of Practice4.1 Three processes of sample division and reduction arecovered as fo
10、llows:4.1.1 Procedure AManual riffles are used for division ofthe sample and mechanical crushing equipment for the reduc-tion of the sample.4.1.2 Procedure BMechanical sample dividers are usedfor the division of the sample and mechanical crushingequipment for the reduction of the sample.4.1.3 Combin
11、ed Procedure A and BThe two proceduresmay be combined at any stage.1This practice is under the jurisdiction of ASTM Committee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.23 on Sampling.Current edition approved June 1, 2011. Published July 2011. Originally approvedin 1962
12、. Last previous edition approved in 2009 as D2013/D2013M 09. DOI:10.1520/D2013_D2013M-11.2For more 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 standard
13、s, visit the ASTM website, www.astm.org, orcontact ASTM 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 1
14、9428-2959, United States.5. Significance and Use5.1 Other standards are used to collect the gross sample:Practice D2234/D2234M allows for one division of the grosssample before crushing. The mass and top size of the gross ordivided sample collected by using these guides and practicesare usually too
15、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, toa top size and mass suitable to the performance of testing. Anybias in the gross or divided sample before adherence to thispra
16、ctice 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 reduction of a sample may occur at morethan one location. Most often, the sample is collected, reduced,and divided (one or more ti
17、mes) 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 division likely occurs before analysis.5.3 In places, this practice requires air drying the samplebefore subsequent reduction. P
18、rocedures 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 tests may require a sample ofdifferent mass or top size. This procedure may be used toprovide a sample of any mass and size con
19、sist 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 Crushers or GrindersJaw, cone, or rotary crusher;hammer mill; roll; or other suitable crusher to reduce thesample to pass the siev
20、e 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 into the crusher. Crushers should be designed andoperated in a manner to minimize the effect of induced aircirculation and thus the
21、 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 Hammer MillCompletely enclosed to avoid loss ofdust or moisture.6.1.3 Porcelain-Jar Ball MillThis mill shall be approxi-mately 230
22、 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 Bucking Board (Chrome Steel) or Mortar (Agate orEquivalent) and PestleOnly for reducing the small fractionof sample, not passing a 2
23、50-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 spout, arotating slotted cone, a reciprocating hopper and fixed cutter,bucket cutter with either bottom dump or inverting discharge,
24、slotted belt, rotary disk divider, mechanical stopped or movingbelt sweeper, or other acceptable devices for dividing thesample. Typical mechanical sample dividers are shown in Fig.1. These illustrate various designs, but other acceptable designsare available.6.2.2 RiffleA manual sample divider that
25、 splits the coalstream into two parts when it is directed through alternatingslots. Riffle slots shall be at least three times the top size of thecoal being divided and have an even number of alternatingslots, in order to achieve similar mass delivered to each catchpan. Riffles shall be enclosed. Th
26、e slope of the feed chutes andriffles shall be at least 60.6.2.2.1 Large RiffleA manual sample divider with at leastfourteen 12.7-mm (12 in.) to 25.4-mm (1 in.) divisions fordividing subsamples of coal passing 2.36 mm (No. 8), and 4.75mm (No. 4) sieves. See Fig. 2.6.2.2.2 Small RiffleA manual sample
27、 divider with at leasttwenty-four 6.35-mm (14 in.) to 9.52-mm (38 in.) divisions fordividing the subsamples of coal passing 250m (No. 60). SeeFig. 3.6.2.2.3 Feed ScoopA feed scoop or pan having straightsides and a width equal to the effective width of the riffle shallbe used to feed the riffle.6.2.2
28、.4 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, the samples arein closed containers attached
29、 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 particles fallgently from top to bottom of
30、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 sizes, withcover and receiver:No. Size4 4.
31、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 storageand transport of the laboratory sampl
32、e. 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 supervision of, personnel knowledgeable ofprope
33、r 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 sampleD2013/D2013M 112division and analysis Sda2be not more than 20 % of the totalvariance of sampling, division, and analysis So2.7.1.1
34、 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 analysis and tests to be performed. A separat
35、emoisture 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 necessary during sample preparation. Test Me
36、thodD3302 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 rapidly and in as few operations aspossible, s
37、ince moisture loss depends on several factors otherthan total moisture content, such as time required for crushing,atmospheric temperature and humidity, and type of crushingequipment.(a) Reciprocating CutterFig. 1(a) shows a section of a cutter which is moved across a stream of coal. At regular inte
38、rvals, the cutter movement is reversed and a sampleincrement is collected on each trip through 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.
39、 One or more cutters may be used.(c) Rotating Hopper and SpoutFig. 1(c) shows the totaling 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 locke
40、d together and rotated on a vertical shaft so that on eachrevolution the common slot operating intercepts the falling stream of coal and collects an increment.FIG. 1 Mechanical Sample DividersD2013/D2013M 1137.3.3 While awaiting preparation, the gross or dividedsample shall be protected from moistur
41、e 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 weight loss or gainshall be used in the calcu
42、lation 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 usedin the calculation of moisture content
43、.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. Procedure9.1 MassThe minimum allowable mass o
44、f 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. 4 for flowchart):9.2.1 It is permissible to air dry the sample before crushing.Samples may require air drying to feed properly
45、 through thereduction and dividing equipment. Sometimes there is aninterest in determining the air-dry loss value before crushing.Air dry in accordance with Test Method D3302.9.2.2 In the reduction and division of gross or dividedsamples for which total moisture content is to be determined,the preca
46、utions 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 (No. 8) sieve taking precautionsin accordance with Section 7.FIG. 2 Large Sample Divider (Riffle)D2013/D2013M 1149.2.3.2 Determine the number
47、of passes required in theriffling operation from the total mass of the gross sample andthe minimum permissible mass in accordance with Table 1.9.2.3.3 Divide the crushed sample by using a large riffle.Riffles properly used will reduce sample variability but cannoteliminate it. A typical enclosed rif
48、fle 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 fullwidth of the riffle. When using any of the preceding containersto feed the riffle, spread the coal evenly in the container, raisethe container,
49、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 not allow thecoal to build up in or above the riffle slots. If it does not flowfreely through the slots, shake or vibrate the riffle to facil
