1、Designation: C 561 91 (Reapproved 2005)An American National StandardStandard Test Method forAsh in a Graphite Sample1This standard is issued under the fixed designation C 561; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method provides a pra
3、ctical determination forthe ash content in a graphite sample.1.2 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-
4、bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 562 Test Method for Moisture in a Graphite Sample3. Significance and Use3.1 This test method provides a practical estimate of non-burnable residues in commercially available graphite materials.The ash values d
5、etermined by this test method are of use incomparing the relative purity of various grades of graphite. Tofacilitate use, this test method institutes simplifications thatpreclude the ability to determine absolutely the ash values ofthe test graphite material due to uncontrolled sources of traceconta
6、mination.3.2 This test method is not intended for use in determiningthe ash content of purified graphites, for example, nuclearmaterials. The relationship between the mineral content of agraphite sample and the ash content of that sample is unknownand is not determined by the application of this tes
7、t method.4. Interferences4.1 Although permitted within the scope of this test method,the use of alumina ceramic crucibles may affect results due todifficulties in obtaining repeatable or proper weights, or both,because of (1) the hygroscopic nature of some ceramiccrucibles, and (2) the possible chem
8、ical combination of traceelements with the ceramic crucible.4.2 Any ash or trace elements introduced to the sample willinfluence results. Contamination can occur during drilling toobtain the sample and during pulverization. (See 6.1.)5. Apparatus5.1 Alumina Ceramic or Platinum Crucible or Dish, suit
9、-able for holding sample (subsequently called sample holder).5.2 Analytical Balance, capable of weighing to 60.0002 g.5.3 Muffle Furnace, capable of reaching 950C (1742F)with controller capable of maintaining a temperature of 950 620C (1742 6 68F).5.4 Platinum or Stainless Steel Wire.5.5 Desiccator,
10、 charged with indicating desiccant.5.6 Drying Oven, air convection type, capable of beingcontrolled to 110 6 2C (230 6 4F).6. Sampling6.1 Samples may be solid or particulate. Solid bodies maybe sampled by removing one or more solid pieces from thebody by, for example, sawing, turning, milling, or fr
11、acturing.Particulate samples may be generated from solid bodies bydrilling, using a carbide drill to minimize contamination, or byother crushing and grinding methods.7. Procedure7.1 Dry the sample in accordance with Test Method C 562,or for a minimum of 16 h in a drying oven at 110 6 2C (2306 4F), a
12、nd allow the sample to cool to room temperature inthe desiccator.7.2 Tare a dried sample holder using an analytical balance to60.002 g. As soon as the sample has cooled to roomtemperature, remove it from the desiccator and weigh a 25- to50-g sample into the tared sample holder. Reweigh the sampleand
13、 sample holder to 60.002 g.7.3 Introduce a slow stream of air into the muffle furnace(Note 1). Place the sample holder containing the sample intothe furnace, then heat the furnace so that the sample reaches500C (932F) in 1 h and 750C (1382F) in 2 h.NOTE 1The stream of air into the furnace should be
14、carefully adjustedso that the sample or ash will not be blown from the dish. The air stream1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.F0 on Manufactured Carbon and Graphite Products.Current
15、 edition approved June 1, 2005. Published August 2005. Originallyapproved in 1965. Last previous edition approved in 2000 as C 56191(2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
16、 information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.may be admitted by leaving the door of the furnace open a slight amount.Exercise care when placing a sample
17、 into a warm furnace so that nosample material will be lost due to drafts.7.4 To aid in oxidation, stir the sample periodically with thewire. The absence of black flecks indicates that ashing iscomplete; at that time raise the furnace temperature to 950C(1742F) for 1 h.7.5 Remove the dish containing
18、 the ash from the furnace,(see Note 1) and cool to room temperature in the desiccator.Following removal from the desiccator, weigh the dish with theash as rapidly as possible.7.6 Replace the sample in the furnace at 950C (1742F) for30 min and repeat the procedure prescribed in 7.5 until aconstant we
19、ight is obtained to 60.002 g.8. Calculation8.1 Calculate the percentage of ash as follows:Ash, % 5 C 2 A!/B 2 A!# 3 100 (1)where:A = weight of the sample holder,B = weight of the sample holder and dried sample,C = weight of the sample holder and ash.9. Report9.1 The report shall include the followin
20、g:9.1.1 Proper identification of the sample, and9.1.2 Results obtained from at least two ash determinationsand their averages.10. Precision and Bias310.1 The precision of this test method was determinedduring a round-robin test among four laboratories testingsamples split from a common sample which
21、was ground to passa No. 60 (250-m) sieve. This sampling method was used forthe round-robin to minimize variations among samples pro-vided to participating laboratories.10.2 On this sample the mean, standard deviation betweenlaboratories and standard deviation within laboratories were,respectively:Me
22、an 0.7286Between laboratories 0.0159Within laboratories 0.012710.3 No bias was noted during this round-robin test; how-ever, the method is empirical and there is no suitable referencematerial that can be used to determine the bias of this testmethod.11. Keywords11.1 ash; carbon; graphiteASTM Interna
23、tional 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 advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely th
24、eir 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 should
25、 be addressed to ASTM International Headquarters. Your comments 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 Standa
26、rds, 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 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:C05-1008.C 561 91 (2005)2
