1、Designation: C 604 02 (Reapproved 2007)1Standard Test Method forTrue Specific Gravity of Refractory Materials by Gas-Comparison Pycnometer1This standard is issued under the fixed designation C 604; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e of revision, the 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 of measure statement was added editorially in March 2009.1. Scope1.1 This test method covers
3、 the determination of the truespecific gravity of solid materials, and is particularly useful formaterials that easily hydrate which are not suitable for test withTest Method C 135. This test method may be used as analternate for Test Method C 135, Test Method C 128, and TestMethod C 188 for determi
4、ning true specific gravity.1.2 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.2.1 ExceptionIn 7.3 the equivalent SI unit is expressedin parenthesis.1.3 This standard does not purport to address all of thesafety concerns,
5、 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 regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 128 Test Method for Density, Relative Dens
6、ity (SpecificGravity), and Absorption of Fine AggregateC 135 Test Method for True Specific Gravity of RefractoryMaterials by Water ImmersionC 188 Test Method for Density of Hydraulic Cement3. Summary of Test Method3.1 The sample is powdered to ensure permeation of gasinto all pores. For practical pu
7、rposes this is assumed to be truewhen the sample passes a No. 325 (45-m) sieve. The volumeof a carefully weighed powdered sample which has first beenheated to drive off moisture and undesired combined water ismeasured by the gas-comparison pycnometer. Density is cal-culated from the sample weight in
8、 grams divided by its volumein cubic centimetres. This is also the specific gravity of thesample at room temperature compared to water at 4C.3.2 The principle of the gas-comparison pycnometer is asfollows: There are two chambers and two pistons as sketchedin Fig. 1. For purposes of illustration, the
9、 chambers areassumed to be equal in volume, and there is no sample in eithercylinder. Under these conditions, with the coupling valveclosed, any change in the position of one piston must beduplicated by an identical stroke in the other in order tomaintain the same pressure on each side of the differ
10、entialpressure indicator.3.3 If a sample, Vx, is inserted into chamber B, the couplingvalve closed and both pistons advanced the same amount fromposition 1 to position 2, the pressures will not remain the same.However the pressures can be maintained equal if piston Binstead is moved only to position
11、 3. Then the remainingdisplacement dx, from position 3 to position 2, is equal to thevolume of the sample, Vx. If piston A always is advancedexactly the same distance each time a measurement is made,the distance that piston B differs from position 2, when thepressures in both cylinders are equal, wi
12、ll always be propor-tional to the volume, Vx. The distance (dx) between positions 2and 3 can be calibrated and made to read directly in terms ofcubic centimetres, employing a digital counter.4. Significance and Use4.1 The true specific gravity of a material is the ratio of itstrue density, determine
13、d at a specific temperature, to the truedensity of water, determined at a specific temperature. Thus,the true specific gravity of a material is a primary propertywhich is related to chemical and mineralogical composition.4.2 This test method is particularly useful for hydratablematerials which are n
14、ot suitable for test with Test MethodC 135.4.3 For refractory raw materials and products the truespecific gravity is a useful value for: classification, detectingdifferences in chemical composition between supposedly like1This test method is under the jurisdiction of ASTM Committee C08 onRefractorie
15、s and is the direct responsibility of Subcommittee C08.03 on PhysicalProperties.Current edition approved March 1, 2007. Published April 2007. Originallyapproved in 1967. Last previous edition approved in 2002 as C 604 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact
16、 ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume 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.samples, indicating miner
17、alogical phases or phase changes,calculating total porosity when the bulk density is known, andfor any other test method that requires this value for thecalculation of results.4.4 This test method is a primary standard method which issuitable for use in specifications, quality control, and researcha
18、nd development. It can also serve as a referee test method inpurchasing contracts or agreements.4.5 Fundamental assumptions inherent in this test methodare the following:4.5.1 The sample is representative of the material in general,4.5.2 The total sample has been reduced to the particle sizespecifie
19、d,4.5.3 No contamination has been introduced during process-ing of the sample,4.5.4 The ignition of the sample has eliminated all free orcombined water without inducing sintering or alteration,4.5.5 An inert gas (helium) has been used in the test, and4.5.6 The test method has been conducted in a met
20、iculousmanner.4.5.7 Deviation from any of these assumptions negates theusefulness of the results.4.6 In interpreting the results of this test method it must berecognized that the specified sample particle size is signifi-cantly finer than specified for Test Method C 135. Even thisfiner particle size
21、 for the sample does not preclude the presenceof some closed pores, and the amount of residual closed poresmay vary between materials or even between samples of thesame or like materials. The values generated by this testmethod may, therefore, be very close approximations ratherthan accurate represe
22、ntations of true specific gravities. Thus,comparisons of results should only be judiciously made be-tween like materials tested by this test method or with fullrecognition of potentially inherent differences between thematerials being compared or the test method used.5. Apparatus5.1 Analytical Balan
23、ce, 200-g capacity, minimum sensitiv-ity 10 mg.5.2 Desiccator, charged with magnesium perchlorate.5.3 Muffle Furnace, capable of heating to 1000C.5.4 Cylinder of Dry Helium Gas, with regulator and gage.5.5 Equipment for Grinding Sample, to pass a No. 325(45-m) sieve without contamination.5.6 Gas-Com
24、parison Pycnometer,3equipped with externalpurge manifold.6. Sample Preparation6.1 Grind a sufficient representative sample for three deter-minations to pass a No. 325 (45-m) sieve. With the Beckmaninstrument the quantity needed is approximately 150 cm3.6.2 After grinding, ignite the total sample at
25、a temperaturesufficient to drive off free moisture and any undesired com-bined water, organic matter, etc., without inducing sintering ofthe powder. In the case of refractory materials that hydrate, theignition temperature is a minimum of 600C for 3 h.6.3 After ignition, place the powdered sample in
26、 a desicca-tor charged with magnesium perchlorate and allow to cool toroom temperature.7. Procedure7.1 Check the gas-comparison pycnometer for zero mea-surement and calibration as specified in the instruction manualfor the instrument.7.2 Take the cooled sample from the desiccator and rapidlyfill the
27、 previously tared sample cup nearly full. Weigh to 10mg. The sample and sample cup must be within 6 2C ofinstrument temperature. With materials that hydrate, once the3A suitable instrument is the Beckman Air Comparison Pycnometer manufac-tured by Beckman Instruments, Inc., 2500 Harbor Blvd., Fullert
28、on, CA 92634.FIG. 1 Simplified Schematic DiagramC 604 02 (2007)12sample is removed from the desiccator the succeeding stepsmust be taken as rapidly as possible to prevent hydration.7.3 Place the sample cup with sample in the pycnometersample compartment and lock firmly into place. Purge thepycnomete
29、r system with dry helium gas at pressures notexceeding 2 psi (13.8 kPa).7.4 Measure the sample volume by the standard proceduregiven in the instruction manual for purge atmosphere volumemeasurement except that the wait period for temperatureequilibration is increased to 60 s.7.5 Repeat the volume me
30、asurement for the same sample,and take the sample volume as the average of the twomeasurements, which must agree within 0.05 cm3.8. Calculation8.1 Calculate the true specific gravity of the sample at roomtemperature as compared to water at 4C as follows:S 5 W/Vwhere:S = true specific gravity,W = sam
31、ple weight, g, andV = sample volume, cm3(average of two measurements).9. Report9.1 Report the true specific gravity to two decimal places asthe average of the values determined on three separate samplesof the material, which individual values must agree within0.01.10. Precision and Bias10.1 An inter
32、laboratory study was run in which randomlydrawn test specimens of two materials (tabular alumina andMulcoa 47) were tested for true specific gravity by gas-comparison pycnometer. Both materials were tested in 4 labs.Replicates per lab in the tabular alumina testing ranged from 3to 9 averaging 6. Rep
33、licates per lab in the Mulcoa 47 testingranged from 3 to 6 averaging 4.75. Number of operators rangedfrom 1 to 3 for both materials. Instruments used in the studywere Beckman Air Comparison Pycnometers at 2 labs and aMicromeritics AccuPyc 1330 at 1 lab. The instrument for the4th lab was not identifi
34、ed. Except for the lack of uniformity innumber of replicate tests and the use of only two materials,Practice E 691 was followed for the design and analysis of thedata, the details are given in ASTM Research Report No.C08:1013.410.2 Test ResultThe precision information given below inthe unit of measu
35、rement (g/cc) is for the comparison of the twotest results. If the difference in the two test results is greaterthan or equal to the applicable 95 % limit there is a 95 %probability that the materials are measurably different. If thedifference in results are less than the applicable 95 % limit, itca
36、nnot said with certainty that the materials are measurablydifferent.Tabular Alumina Mulcoa 47Average Test Value 3.952 2.79095 % repeatability limit (within laboratory) 0.026 0.01695 % reproducibility limit (between laboratories) 0.053 0.048The above terms (repeatability limit and reproducibilitylimi
37、t) are used as specified in Practice E 177. The respectivestandard deviations among test results may be obtained bydividing the above limit values by 2.8.10.3 BiasNo justifiable statement can be made on the biasof the procedure in this test method for measuring true specificgravity because no refere
38、nce material was readily available.11. Keywords11.1 gas comparison pycnometer; hydratable materials; re-fractory materials; true specific gravityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of
39、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 committee and must be reviewed every five
40、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 meeting of theresponsible technical com
41、mittee, 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 Drive, PO Box C700, West Conshohocken, PA 1
42、9428-2959,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).4Details are given in a research report available from ASTM InternationalHeadquarters. Request RR:C081013.C 604 02 (2007)13
