1、Designation:D2013/D2013M11 Designation: D2013/D2013M 12Standard 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 y
2、ear of last revision. A number 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 reduc
3、tion and division of gross or divided samples, and the preparation of composite samples, upto and including the individual portions for laboratory analysis.1.2 Reduction and division procedures are prescribed for coals of the following groups:1.2.1 Group A includes coals that have been cleaned in al
4、l sizes.1.2.2 Group B includes all other coals. Unknown coals are to be considered under Group B.1.2.3 Group A allows smaller weight laboratory samples to be retained than Group B. These lower weights may be used forparticular coals if they have been shown, by using the procedures of Annex A1.2, to
5、give a sample preparation and analysisvariance which is no more than 20 % of the total analysis variance.1.3 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
6、be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish approp
7、riate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D121 Terminology of Coal and CokeD2234/D2234M Practice for Collection of a Gross Sample of CoalD3174 Test Method for Ash in the Analysis Sample of Coal a
8、nd Coke from CoalD3302 Test Method for Total Moisture in CoalD4749 Test Method for Performing the Sieve Analysis of Coal and Designating Coal SizeE11 Specification for Woven Wire Test Sieve Cloth and Test SievesE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE456 Terminolog
9、y Relating to Quality and Statistics3. Terminology3.1 Definitions of Terms Specific to This StandardNo terms are used which are specific to this practice. Many terms used inthis practice may be found in Terminologies D121 and E456 and in Practice E177.4. Summary of Practice4.1 Three processes of sam
10、ple division and reduction are covered as follows:4.1.1 Procedure AManual riffles are used for division of the sample and mechanical crushing equipment for the reduction ofthe sample.4.1.2 Procedure BMechanical sample dividers are used for the division of the sample and mechanical crushing equipment
11、 forthe reduction of the sample.1This practice is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.23 on Sampling.Current edition approved JuneApril 1, 2011.2012. Published July 2011.June 2012. Originally approved in 1962. Last previo
12、us edition approved in 20092011 asD2013/D2013M09.D2013/D2013M 11. DOI: 10.1520/D2013_D2013M-112.2For more detailed explanation of this practice see Keller, G. E., “Determination of Quantities Needed in Coal Sample Preparation and Analysis,” Transactions,Vol232, 1965, pp. 218-226.3For referenced ASTM
13、 standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user
14、 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 only the current versionof the standard as
15、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.4.1.3 Combined Procedure A and BThe two procedures may be combined at any stage.5. Significance and Use5.1 Other standards are
16、 used to collect the gross sample: Practice D2234/D2234M allows for one division of the gross samplebefore crushing. The mass and top size of the gross or divided sample collected by using these guides and practices are usuallytoo large for chemical or physical testing. Practice D2013 provide instru
17、ctions for reducing and dividing the gross or dividedsample, by on-line or off-line processes, or both, to a top size and mass suitable to the performance of testing.Any bias in the grossor divided sample before adherence to this practice will remain in the final sample resulting from use of this pr
18、actice. Therefore,carefully select the standard to be used to collect the gross sample.5.2 Division and reduction of a sample may occur at more than one location. Most often, the sample is collected, reduced, anddivided (one or more times) by use of a mechanical sampling system. The remaining sample
19、 may be further divided on-site tofacilitate transporting it to the laboratory where further reduction and division likely occurs before analysis.5.3 In places, this practice requires air drying the sample before subsequent reduction. Procedures for air drying and air-dry lossdetermination are provi
20、ded in Test Method D3302.5.4 Most often, samples are reduced and divided to an analysis sample. However, some tests may require a sample of differentmass or top size. This procedure may be used to provide a sample of any mass and size consist from the gross or divided sampleto, and including, the an
21、alysis sample.5.5 This practice also specifies how to prepare composite samples, if required.6. Apparatus6.1 Crushers or GrindersJaw, cone, or rotary crusher; hammer mill; roll; or other suitable crusher to reduce the sample topass the sieve designated in 6.4. Hard steel or chilled iron plate with t
22、amper, sledge, or hand bar may be used for preliminarycrushing of any large lumps in the sample before feeding into the crusher. Crushers should be designed and operated in a mannerto minimize the effect of induced air circulation and thus the potential for drying the coal.6.1.1 Pulverizer or MillFo
23、r final reduction of laboratory sample to the 250-m (No. 60) sieve size, the following equipmentmay be used:6.1.2 Hammer MillCompletely enclosed to avoid loss of dust or moisture.6.1.3 Porcelain-Jar Ball MillThis mill shall be approximately 230 mm 9.0 in. in diameter and 250 mm 10.0 in. in heightwit
24、h smooth, hard, well-rounded, flint pebbles, or equivalent, that do not increase ash content of the sample.6.1.4 Bucking Board (Chrome Steel) or Mortar (Agate or Equivalent) and PestleOnly for reducing the small fraction ofsample, not passing a 250-m (No. 60) sieve after pulverization.6.2 Sample Div
25、iders:6.2.1 MechanicalA mechanical sample divider using a reciprocating or rotating cutter, a rotating hopper and spout, a rotatingslotted cone, a reciprocating hopper and fixed cutter, bucket cutter with either bottom dump or inverting discharge, slotted belt,rotary disk divider, mechanical stopped
26、 or moving belt sweeper, or other acceptable devices for dividing the sample. Typicalmechanical sample dividers are shown in Fig. 1. These illustrate various designs, but other acceptable designs are available.6.2.2 RiffleA manual sample divider that splits the coal stream into two parts when it is
27、directed through alternating slots.Riffle slots shall be at least three times the top size of the coal being divided and have an even number of alternating slots, in orderto achieve similar mass delivered to each catch pan. Riffles shall be enclosed. The slope of the feed chutes and riffles shall be
28、 atleast 60.6.2.2.1 Large RiffleA manual sample divider with at least fourteen 12.7-mm (12 in.) to 25.4-mm (1 in.) divisions for dividingsubsamples of coal passing 2.36 mm (No. 8), and 4.75 mm (No. 4) sieves. See Fig. 2.6.2.2.2 Small RiffleA manual sample divider with at least twenty-four 6.35-mm (1
29、4 in.) to 9.52-mm (38 in.) divisions fordividing the subsamples of coal passing 250m (No. 60). See Fig. 3.6.2.2.3 Feed ScoopAfeed scoop or pan having straight sides and a width equal to the effective width of the riffle shall be usedto feed the riffle.6.2.2.4 Feed ChuteA feed chute shall be used as
30、shown in Fig. 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 used for mixing the analysis sample. In this device, the samples are inclosed containers attached to the rim of a wheel at an angle of 45
31、 with the horizontal wheel shaft. The wheel provides space fora number of containers depending on its diameter and is turned slowly by a small motor and reduction gear. The wheel should berotated at a speed so that the particles fall gently from top to bottom of the container, mixing the sample thor
32、oughly. The containershould be about half full and never more than two thirds full to obtain good mixing of the sample.6.4 SievesA set of sieves whose dimensions are in accordance with Specification E11, of the following sizes, with cover andreceiver:D2013/D2013M 122No. Size4 4.75 mm8 2.36 mm20 850
33、m60 250 m6.5 Laboratory Sample Containers Heavy vapor-impervious bags, properly sealed, or noncorroding cans such as those withan airtight top, friction top, or screwtop sealed with a rubber gasket and pressure-sensitive tape for use in storage and transportof the laboratory sample. Glass containers
34、, sealed with rubber gaskets, may be used, but care must be taken to avoid breakage intransport.7. Precautions7.1 GeneralThe preparation of the gross or divided sample, or the composite sample, shall be performed by, or under thedirect supervision of, personnel knowledgeable of proper sample handlin
35、g practices. Sample preparation should be checked at(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 through the coal stream.(b) Rotating CutterF
36、ig. 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 totaling hopper that receives the crushed sample
37、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 operating intercepts the falling stream of coa
38、l and collects an increment.FIG. 1 Mechanical Sample DividersD2013/D2013M 123intervals by the methods described in Annex A1 or Annex A2. It is necessary that the variance of sample division and analysis Sda2be not more than 20 % of the total variance of sampling, division, and analysis So2.7.1.1 The
39、 sample preparation operations should be performed in an enclosed space, roofed, cool, and free from excessive airmovements.7.2 Number of TestsBefore preparing the gross or divided sample, or the composite sample, consider the number and natureof the analysis and tests to be performed. A separate mo
40、isture laboratory sample may be required, and portions may be requiredfor grindability and other tests. Also, a reserve sample may be desired in case a check analysis or test is required.7.3 This practice specifies situations when air drying the sample is necessary during sample preparation. Test Me
41、thod D3302specifies procedures for air drying and calculation of percent air dry loss.7.3.1 Calculate and record air-dry loss determination each time air drying is performed.7.3.2 In handling, reducing, and dividing the sample, all operations shall be done rapidly and in as few operations as possibl
42、e,since moisture loss depends on several factors other than total moisture content, such as time required for crushing, atmospherictemperature and humidity, and type of crushing equipment.7.3.3 While awaiting preparation, the gross or divided sample shall be protected from moisture change as a resul
43、t of exposureto rain, snow, wind, and sun on contact with absorbent materials.7.3.4 Whenever subsamples are stored or transported, the containers and subsample shall be weighed and equilibrated to thenew atmosphere by air drying, and the weight loss or gain shall be used in the calculation of moistu
44、re content.7.4 Whenever a distinct change of humidity occurs during the course of preparation of an air-dried subsample, the subsampleshall be weighed and its moisture equilibrated with the new atmosphere, and the loss or gain in mass shall be used in the calculationof moisture content.FIG. 2 Large
45、Sample Divider (Riffle)D2013/D2013M 1248. Sieve Tests8.1 The errors of sample division are sensitive to the top size, and therefore, it is important to make a periodic sieve test of theproduct of the sample crusher. Sieve tests shall be made and reported in accordance with Test Method D4749.9. Proce
46、dure9.1 MassThe minimum allowable mass of the sample at any stage depends on the top size, the variability of the constituentsought, and the degree of precision desired (Table 1).9.2 Reduction and Division (See Fig. 4 for flowchart):9.2.1 It is permissible to air dry the sample before crushing. Samp
47、les may require air drying to feed properly through thereduction and dividing equipment. Sometimes there is an interest in determining the air-dry loss value before crushing. Air dry inaccordance with Test Method D3302.FIG. 3 Small Sample Divider (Riffle)TABLE 1 Preparation of Laboratory SampleCrush
48、 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 subsample b
49、y 500 g.D2013/D2013M 1259.2.2 In the reduction and division of gross or divided samples for which total moisture content is to be determined, theprecautions 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 of 4.75-mm (No. 4) or 2.36-mm (No. 8) sieve taking precautions inaccordance with Section 7.9.2.3.2 Determine the number of passes required in the riffling operation from the total mass of the gross sample and theminimum permissible mass in accordance with Tabl
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