1、Designation: C 492 92 (Reapproved 2008)Standard Test Method forHydration of Granular Dead-Burned Refractory Dolomite1This standard is issued under the fixed designation C 492; 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.1. Scope1.1 This test method covers the determination of the amountof hydration of a granular dead-burned refractory dolomit
3、ewhen exposed to moist air.1.2 The values stated in inch-pound units are to regarded asthe standard. The values given in parentheses are for informa-tion only.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
4、 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:2C92 Test Methods for Sieve Analysis and Water Content ofRefractory MaterialsE11 Specification for Wire Cloth and
5、Sieves for TestingPurposes3. Significance and Use3.1 The hydration of dead-burned dolomite grains is animportant aspect of both manufacturing and using such grains.Moisture from any source will cause the grains to partiallydisintegrate, eventually making the dead-burned dolomite unfitfor use. This t
6、est method may prove useful for determining, ina relative manner, which grains are more resistant to hydrationthan others.3.2 Data from one laboratory might help in establishinginternal limits for determining whether a particular batch ofgrain is suitable for refractory production. However, this tes
7、tmethod takes great care to run, and is not recommended as aquality control test. Possibly, a specification might be devel-oped between two parties if sufficient care in establishing thebias between the laboratories is carried out.4. Apparatus4.1 Sieve, ASTM No. 40 (425-m) (equivalent to a 35-meshTy
8、ler Standard Series) conforming to Specification E11, withpan and cover.4.2 Glass Petri Dishes, 95 by 20-mm.4.3 Circulating Hot-Air Oven, capable of operating at 220 to230F (104 to 110C).4.4 Steam-Humidity Cabinet, to be maintained at 160 6 2F(71 6 1C) and 85 6 3 % humidity.34.5 Scale, having a capa
9、city of 200 g, accurate to 0.02 g.5. Sampling5.1 The sample used shall be quartered or riffled so that it istypical of the material being tested both in screen size andoiling. All material passing the No. 40 (425-m) sieve shall beremoved from this sample by screening. All screening shall bedone in a
10、ccordance with Test Methods C92 for dry sieveanalysis.6. Procedure6.1 Place a 100 6 0.1-g portion of the representative sampleretained on the No. 40 (425-m) sieve sample in a 95 by20-mm Petri dish. Then place this dish in a hot-air oven for1/2 h at 220 to 230F (104 to 110C) to prevent condensationof
11、 water on the sample when placed in a hot steam-humiditycabinet.6.2 Transfer the Petri dish containing the sample from thehot-air oven to the steam-humidity cabinet, and cover with aglass plate at an angle of 45 to prevent dripping on the sample.The edges of the glass plate shall overhang the Petri
12、dish byabout34 in. (19 mm).6.3 Maintain the steam-humidity cabinet at 160 6 2F (716 1C) and 85 6 3 % humidity for 24 h. The time to reachthese conditions shall be approximately12 h. Then immedi-ately remove the Petri dish from the cabinet and place in ahot-air oven at 220 to 230F (104 to 110C) for12
13、 h or until aconstant weight is attained. Then screen the sample on a No. 40(425-m) sieve and weigh the material passing the sieve to thenearest 0.1 g. Always run the tests in triplicate.1This test method is under the jurisdiction of ASTM Committee C08 onRefractories and is the direct responsibility
14、 of Subcommittee C08.04 on ChemicalBehaviors.Current edition approved March 1, 2008. Published March 2008. Originallyapproved in 1962. Last previous edition approved in 2003 as C492 92 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser
15、viceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3An apparatus manufactured by the American Instrument Co., 8030 GeorgiaAve., Silver Spring, MD, or the Electric Hotpack Co., Philadelphia, PA, has beenfound suitable for
16、 this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Report7.1 Report the hydration of a sample as the average percent-age of material passing the No. 40 (425-m) sieve after thehydration test.8. Precision and Bias8.1 Inte
17、rlaboratory Study:8.1.1 An interlaboratory test program between four labora-tories was conducted. Each laboratory tested three dolomiticmaterials. Each of the three dolomitic materials was tested fourtimes.8.1.2 No ruggedness test was run on this test method priorto conducting the interlaboratory st
18、udy.8.2 Precision:8.2.1 RepeatabilityThe maximum permissible differencedue to test error between two test results obtained by oneoperator on the same material is given by the repeatabilityinterval and the relative repeatability interval (coefficient ofvariation). The 95 % repeatability intervals are
19、 given in Table1. Two test results that do not differ by more than therepeatability interval will be considered to be from the samepopulation, and, conversely, two test results that do differ bymore than the repeatability interval will be considered to befrom different populations.8.2.2 Reproducibil
20、ityThe maximum permissible differ-ence due to test error between two test results obtained by twooperators in different laboratories on the same type of materialusing the same type of test equipment is given by thereproducibility interval and relative reproducibility interval(coefficient of variatio
21、n). The 95 % reproducibility intervalsare given in Table 1. Two test results that do not differ by morethan the reproducibility interval will be considered to be fromthe same population, and, conversely, two test results that dodiffer by more than the reproducibility interval will be consid-ered to
22、be from different populations.8.3 BiasThis test method does not lend itself to a state-ment of bias.9. Keywords9.1 dolomite; grain; humidity cabinet; hydration resistance;refractories;ASTM International takes no position respecting the validity of any patent rights asserted in connection with any it
23、em 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 at any time by the responsible technical com
24、mittee 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 comments will receive careful consideration at a
25、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 copyrighted by ASTM International, 100 Barr Harbor Driv
26、e, 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.or
27、g).TABLE 1 Precision DataMaterialNumberAverage, XStandardWithin, SrDeviationBetween, SRRepeatabilityInterval, rReproducibilityIntervalCoefficient of Variation RelativeRepeatability,% rRelativeReproducibility,% RWithin Lab,VrBetween Labs,VR1 23.94 0.8752 1.513 2.450 4.236 3.656 6.320 10.23 17.692 4.820 0.2325 0.5299 0.6510 1.484 4.824 10.99 13.51 30.793 3.645 0.1355 0.3007 0.3795 0.8419 3.717 8.250 10.41 23.10C 492 92 (2008)2
