1、Designation: D6791 11 (Reapproved 2017)1Standard 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, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEUnits formatting was corrected editorially in February 2017.1. Scope1.1 This test method covers a laboratory vibra
3、tion millmethod for the determination of the grain stability of calcinedpetroleum coke 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 ma
4、y result inpoor quality of baked blocks.1.2 The values stated in SI units are to be 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
5、 user of this standard to establish appro-priate safety and health practices and determine 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 Prepar
6、ing Coal Samples for AnalysisD2234/D2234M Practice for Collection of a Gross Sampleof 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 Tes
7、tSieves2.2 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 todevelop crystalline structure.3.1.2 petr
8、oleum 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 to a 4 mm to 8 mm fraction. The resultantsample is weighed so that
9、two separate portions of 100.0 g 60.5 g mass are obtained. The samples are place into thelaboratory mill and ground for a specified period of time.Aftergrinding the sample is screened and the mass of the +4 mmmaterial is determined. The grain stability is the percent of theoriginal material remainin
10、g 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 Calcined petroleum cokes have to be relatively easy togrin
11、d for fines production but strong enough to withstandforming pressures and thermal stresses occurring 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 t
12、est method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved Jan. 1, 2017. Published February 2017. Originallyap
13、proved in 2002. Last previous edition approved in 2011 as D6791 11. DOI:10.1520/D6791-11R17E01.2For referenced ASTM standards, 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 Documen
14、t Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standar
15、d was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.17. Appar
16、atus7.1 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 E11.7.4 Laboratory Vibration Mill4, having two grindingvessels, each filled with 1 kg of clean, hard steel balls, diameter10 mm 6 0.4 mm. The m
17、ain features of the mill are shown inFigs. 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 withou
18、t any fastenings 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 ampli
19、tude of the vibration shall be4mm6 0.5 mm. A reference disc is fitted to the front of themachine to measure the amplitude of vibration.7.4.3 The motor shall be capable of 1450 rmin to1470 rmin. The motor may be set up for 50 Hz rather than60 Hz power.Atachometer can be used to verify that the motori
20、s the specified r/min. The motor speed can be regulated witha dc speed controller to adjust it to the specified r/min. Thebearing housing is rigidly connected to the bearings. The shaftrotates inside the bearings with two steel imbalance discsattached and is connected to the motor by way of the clut
21、ch.The imbalance discs are 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
22、rubber sealing ring. The lid is held in place by a clampfitted with a wing nut.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
23、areaware of alternative suppliers, please provide this information to ASTM Interna-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 = gr
24、inding vessels9 = motor13 = quick release catchNOTE 1All dimensions are in millimetres.FIG. 1 Laboratory Vibration Mill (Front View)D6791 11 (2017)128. Sample Preparation8.1 For recommended practice for obtaining, handling, andpreparing coke samples, refer to Practices D346, D2013,D2234/D2234M, D696
25、9, D6970, and ISO 6375. Do notprecrush the sample. Sieve the sample to collect 200 g of cokeof grain size between 4 mm and 8 mm.9. Procedure9.1 Carefully place 1 kg of the steel balls and 100 g 6 0.5 gof the 4 mm to 8 mm fraction of the sieved test sample in eachgrinding vessel and close the lid. Re
26、cord the weight to thenearest 0.1 g. Attach the vessels to the vibration mill.9.2 Turn the mill on and grind the sample for 3.5 min 6 2sas 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
27、 60 horizontal movements in about half aminute. The steel 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
28、contents of the other vessel and recordas vessel 2, m4.10. Calculation10.1 The grain stability (GS) of the calcined petroleumcoke, expressed in percent, is given by the equation:GS 5GS11GS22512Fm3m11m4m2G3100 (1)where:GS1= grain stability for vessel 1 in %,GS2= grain stability for vessel 2 in %,m1=
29、mass of test sample placed in vessel 1, g,m2= mass of test sample 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 the repeatabilityof the test metho
30、d, report the result, GS, as the mean of thesimultaneous duplicate determinations GS1and GS2,tothenearest 0.01 %.2 = common baseplate3 = special clutch4 = flatsprings5 = adjustable straps6 = bearing7,8 = grinding vessels9 = motor10 = discs11 = bearing housing12 = shaftFIG. 2 Laboratory Vibration Mil
31、l (Side View)D6791 11 (2017)1310.3 If GS1and GS2differ by more than 2 the repeat-ability of the test method, repeat the procedure detailed inSection 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
32、 this test method as determined by thestatistical examination 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,NOTE 1All dimension
33、s are in millimetres.FIG. 3 Laboratory Vibration Mill (Ground Plan)10 = discsNOTE 1All dimensions are in millimetres.FIG. 4 Imbalance DiscsD6791 11 (2017)14will 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 Individu
34、al results should not differ by more than2%.12.1.2 ReproducibilityThe difference 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 cas
35、e in twenty.12.1.2.1 Individual results should not differ by more than3%.12.1.3 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 stabilityASTM I
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37、ely 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 reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand
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39、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. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at
40、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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ = lid16 = rubber sealing ring17 = clamp18 = wing nutNOTE 1All dimensions are in millimetres.FIG. 5 Grinding VesselD6791 11 (2017)15
