1、Designation: D6791 11Standard Test Method forDetermination of Grain Stability of Calcined PetroleumCoke1This standard is issued under the fixed designation D6791; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 stability of calcinedpetroleum c
3、oke for the manufacture of carbon products used inthe smelting of aluminum. Calcined petroleum coke with poormechanical strength may become degraded during mixing.Poor grain stability will affect the grain size and may result inpoor quality of baked blocks.1.2 The values stated in SI units are to be
4、 regarded asstandard. No other units of measurement are included in thisstandard.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 de
5、termine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD2013 Practice for Preparing Coal Samples for AnalysisD2234/D2234M Practice for Collection of a Gross Sample
6、of CoalD6969 Practice for Preparation of Calcined Petroleum CokeSamples for AnalysisD6970 Practice for Collection of Calcined Petroleum CokeSamples for AnalysisE11 Specification for Woven Wire Test Sieve Cloth and TestSieves2.2 ISO Standard:3ISO 6375 Carbonaceous Materials for the Production ofAlumi
7、numCoke for ElectrodesSampling3. Terminology3.1 Definitions:3.1.1 calcined petroleum coke, npetroleum coke that hasbeen thermally treated to drive off the volatile matter and todevelop crystalline structure.3.1.2 petroleum coke, nsolid, carbonaceous residue pro-duced by thermal decomposition of heav
8、y 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 resultantsample is weighed so that two separate portions of 100.0 6 0.5g mass are obtained. The samples are place into the labo
9、ratorymill 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 the originalmaterial remaining on the +4 mm sieve.5. Significance and Use5.1 The grain stability of calcined petroleum cok
10、e 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 Calcined petroleum cokes have to be relatively easy togrind for fines production but strong enough to withstandforming pressures and thermal stresses o
11、ccurring when theanodes are used in the reduction process.6. Interferences6.1 No material normally applied to the calcined petroleumcoke is found to cause analytical interference with this proce-dure.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricant
12、s and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved June 1, 2011. Published July 2011. Originally approvedin 2002. Last previous edition approved in 2006 as D679106. DOI: 10.1520/D6791-11.2For referenced ASTM st
13、andards, 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.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Flo
14、or, New York, NY 10036, http:/www.ansi.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Apparatus7.1 Analytical Balance, accurate to 60.1 g.7.2 Rifflers, with ho
15、ppers and closures.7.3 Wire Sieves,8mm(516 in.) and 4 mm (5 mesh), meetingSpecification E11.7.4 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 the mill are shown in Figs.1-5.7.4.1 The mill and driv
16、e 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 or anchorage. The grindingvessels are secured by adju
17、stable 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 vibration shall be 46 0.5 mm. A reference disc is fitted t
18、o 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. The motor speed can be regulated with a dc speedcontro
19、ller 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 shown in Fig. 4.7.4.4 The imbalance discs rotate ecc
20、entrically 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 lid is held in place by a clampfitted with a wing nut.
21、7.4.5 The electric motor is linked to a timer switch having aprecision of 62s.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 Inte
22、rna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.1 = mill2 = common base plate4 = flat springs5 = adjustable straps7,8 = grinding vessels9 = motor13 = quick release catchNOTEAll dimensions are in millim
23、etres.FIG. 1 Laboratory Vibration Mill (Front View)D6791 1128. Sample Preparation8.1 For recommended practice for obtaining, handling, andpreparing coke samples, refer to Practices D346, D2013,D2234/D2234M, D6969, D6970, and ISO 6375. Do not pre-crush the sample. Sieve the sample to collect 200 g of
24、 coke ofgrain size between 4 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 vessels to the vibration mill.9.2 Turn the mill
25、 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 steel balls will remain on the 8-mm sieve,
26、 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, m4.10. Calculation10.1 The grain stability
27、 (GS) of the calcined petroleumcoke, expressed in 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 sample placed in vessel 2, g,m3=
28、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 duplicate determinations GS1an
29、d GS2, to thenearest 0.01 %.2 = common baseplate3 = special clutch4 = flatsprings5 = adjustable straps6 = bearing7,8 = grinding vessels9 = motor10 = discs11 = bearing housing12 = shaftFIG. 2 Laboratory Vibration Mill (Side View)D6791 11310.3 If GS1and GS2differ by more than =2 3 therepeatability of
30、the test method, repeat the procedure detailedin Section 10. Reject all the results.11. 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 of interlaboratory test result
31、s 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,NOTEAll dimensions are in millimetres.FIG. 3 Laboratory Vibration Mill (Ground Plan)10 = discsNOTEAll dimension
32、s are in millimetres.FIG. 4 Imbalance DiscsD6791 114will in the long run, in normal and correct operation of the testmethod, exceed the following values only in one case intwenty.12.1.1.1 Individual results should not differ by more than2%.12.1.2 ReproducibilityThe difference between two singleand i
33、ndependent 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%.12.1.3 BiasSince there is not a
34、ccepted 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 changes to this standard since t
35、he last issue(D679106) that may impact the use of this standard.(1) Revised 1.1, 2.1, 5.2, 8.1, and 10.1.15 = lid16 = rubber sealing ring17 = clamp18 = wing nutNOTEAll dimensions are in millimetres.FIG. 5 Grinding VesselD6791 115ASTM International takes no position respecting the validity of any pat
36、ent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised 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
37、 at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comm
38、ents will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If 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 copyrighte
39、d by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D6791 116
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