1、Designation: D 6791 06An American National StandardStandard Test Method forDetermination of Grain Stability of Calcined PetroleumCoke1This standard is issued under the fixed designation D 6791; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers a laboratory vibration millmethod for the determination of the grain
3、stability of calcinedcoke for the manufacture of carbon products used in thesmelting of aluminum. Calcined coke with poor mechanicalstrength may become degraded during mixing. Poor grainstability will affect the grain size and may result in poor qualityof baked blocks.1.2 The values stated in accept
4、able metric units are to beregarded as the standard.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 to establish appro-priate safety and health practices and determine the applica-bility of
5、 regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD 2013 Practice for Preparing Coal Samples for AnalysisD 2234/D 2234M Practice for Collection of a Gross Sampleof CoalE11 Specification
6、for Wire Cloth and Sieves for TestingPurposes2.2 ISO Standard:3ISO 6375 Carbonaceous Materials for the Production ofAluminumCoke for ElectrodesSampling3. Terminology3.1 Definitions:3.1.1 calcined petroleum coke, npetroleum coke that hasbeen thermally treated to drive off the volatile matter and tode
7、velop crystalline structure.3.1.2 petroleum coke, nsolid, carbonaceous residue pro-duced by thermal decomposition of heavy petroleum fractions,or cracked stocks, or both.4. Summary of Test Method4.1 A representative sample of calcined petroleum coke isdried and screened toa4to8mmfraction. The result
8、antsample is weighed so that two separate portions of 100.0 6 0.5g mass are obtained. The samples are place into the laboratorymill and ground for a specified period of time. After grindingthe sample is screened and the mass of the +4 mm material isdetermined. The grain stability is the percent of t
9、he originalmaterial remaining on the +4 mm sieve.5. Significance and Use5.1 The grain stability of calcined petroleum coke deter-mines the resistance to breakdown of +4 mm particles used inthe manufacture of carbon anodes for use in the reductionprocess of aluminum.5.2 Cokes have to be relatively ea
10、sy to grind for finesproduction but strong enough to withstand forming pressuresand thermal stresses occurring when the anodes are used in thereduction process.6. Interferences6.1 No material normally applied to the calcined petroleumcoke is found to cause analytical interference with this proce-dur
11、e.7. Apparatus7.1 Analytical Balance, accurate to 60.1 g.7.2 Rifflers, with hoppers and closures.7.3 Wire Sieves,8mm(516 in.) and 4 mm (5 mesh), meetingSpecification E11.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibi
12、lity of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved July 1, 2006. Published July 2006. Originally approvedin 2002. Last previous edition approved in 2002 as D 679102.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcon
13、tact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.1*A Summary of Changes section appea
14、rs at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.4 Laboratory Vibration Mill4, having two grinding ves-sels, each filled with 1 kg of clean, hard steel balls, diameter 106 0.4 mm. The main features of t
15、he mill are shown in Figs.1-5.7.4.1 The mill and drive motor are mounted on a commonbase plate. The grinding vessels are installed in the body of themill, which is supported by four soft, flat springs. The springsuspension system is designed to allow the machine to beoperated without any fastenings
16、or anchorage. The grindingvessels are secured by adjustable straps which have a quick-release catch. The oscillator is supported on a bearing, fitted tothe body of the mill, and is driven by the motor by way of aspecial clutch and a hollow flexible shaft.7.4.2 The peak-to-peak amplitude of the vibra
17、tion shall be 46 0.5 mm. A reference disc is fitted to the front of the machineto measure the amplitude of vibration.7.4.3 The motor shall be capable of 1450 to 1470 rpm. Themotor may be set up for 50 Hz rather than 60 Hz power. Atachometer can be used to verify that the motor is the specifiedrpm. T
18、he motor speed can be regulated with a dc speedcontroller to adjust it to the specified rpm. The bearing housingis rigidly connected to the bearings. The shaft rotates inside thebearings with two steel imbalance discs attached and isconnected to the motor by way of the clutch. The imbalancediscs are
19、 shown in Fig. 4.7.4.4 The imbalance discs rotate eccentrically and the entireoscillating mass follows with a phase lag of 180, supported bythe springs. Each grinding vessel (see Fig. 5) has a total volumeof 1 L and an effective volume of 0.3 L. It is closed by a lidwith a rubber sealing ring. The l
20、id is held in place by a clampfitted with a wing nut.4The sole source of supply of the vibration mill is Siebtechnik GmbH, P.O.Box/Postfach 10 17 51, D-25417 MUELHEIM an der RUHR, Germany. If you areaware of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters.
21、Your comments will receive careful consideration at a meetingof the responsible technical committee1which you may attend.1 = mill2 = common base plate4 = flat springs5 = adjustable straps7,8 = grinding vessels9 = motor13 = quick release catchNOTEAll dimensions are in millimetres.FIG. 1 Laboratory Vi
22、bration Mill (Front View)D67910627.4.5 The electric motor is linked to a timer switch having aprecision of 62s.8. Sample Preparation8.1 For recommended practice for obtaining, handling, andpreparing coke samples, refer to Test Methods D 346, D 2013,D 2234/D 2234M and ISO 6375. Do not precrush the sa
23、mple.Sieve the sample to collect 200 g of coke of grain size between4 and 8 mm.9. Procedure9.1 Carefully place 1 kg of the steel balls and 100 6 0.5 gof the 4 to 8 mm fraction of the sieved test sample in eachgrinding vessel and close the lid. Record the weight to thenearest 0.1 g. Attach the vessel
24、s to the vibration mill.9.2 Turn the mill on and grind the sample for 3.5 min 6 2s as measured by the timer switch.9.3 Carefully empty the contents of one vessel on to an8-mm sieve, placed on top of a 4-mm sieve. Screen by hand,using approximately 60 horizontal movements in about half aminute. The s
25、teel balls will remain on the 8-mm sieve, and partof the granular material will remain on the 4-mm sieve.9.4 Weigh the portion of granular material that remains onthe 4-mm sieve to the nearest 0.01 g and record as vessel 1, m3.9.5 Repeat with the contents of the other vessel and recordas vessel 2, m
26、4.10. Calculation10.1 The grain stability (GS) of the calcined coke, expressedin percent, is given by the equation:GS 5GS11 GS22512Fm3m11m4m2G3 100 (1)where:GS1= grain stability for vessel 1 in %,GS2= grain stability for vessel 2 in %,m1= mass of test sample placed in vessel 1, g,m2= mass of test sa
27、mple placed in vessel 2, g,m3= mass of test sample from vessel 1 retained on the 4mm sieve, g, andm4= mass of test sample from vessel 2 retained on the 4mm sieve, g.10.2 If GS1and GS2differ by less than =2 3 the repeat-ability of the test method, report the result, GS, as the mean ofthe simultaneous
28、 duplicate determinations GS1and GS2, to thenearest 0.01 %.10.3 If GS1and GS2differ by more than =2 3 therepeatability of the test method, repeat the procedure detailedin Section 10. Reject all the results.2 = common baseplate3 = special clutch4 = flatsprings5 = adjustable straps6 = bearing7,8 = gri
29、nding vessels9 = motor10 = discs11 = bearing housing12 = shaftFIG. 2 Laboratory Vibration Mill (Side View)D679106311. Report11.1 Report the average of the two vessels to the nearestwhole percent.12. Precision and Bias12.1 The precision of this test method as determined by thestatistical examination
30、of interlaboratory test results is asfollows:12.1.1 RepeatabilityThe difference between successiveresults by the same operator using the same apparatus underconstant operating conditions on the identical test materials,will in the long run, in normal and correct operation of the testmethod, exceed t
31、he following values only in one case intwenty.12.1.1.1 Individual results should not differ by more than2%.NOTEAll dimensions are in millimetres.FIG. 3 Laboratory Vibration Mill (Ground Plan)10 = discsNOTEAll dimensions are in millimetres.FIG. 4 Imbalance DiscsD679106412.1.2 ReproducibilityThe diffe
32、rence between two singleand independent results obtained by different laboratories onidentical test materials will in the long run, in normal andcorrect operation of the test method, exceed the followingvalues only in one case in twenty.12.1.2.1 Individual results should not differ by more than3%.12
33、.1.3 BiasSince there is not accepted reference materialsuitable for determining the bias for the procedure in this testmethod, no statement on bias is being made.13. Keywords13.1 calcined petroleum coke; grain stabilitySUMMARY OF CHANGESSubcommittee D02.05 has identified the location of selected cha
34、nges to this standard since the last issue(D 679102) that may impact the use of this standard.(1) Revised 3.1.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advis
35、ed that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either r
36、eapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If
37、you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individu
38、al reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).15 = lid16 = rubber sealing ring17 = clamp18 = wing nutNOTEAll dimensions are in millimetres.FIG. 5 Grinding VesselD6791065
