1、Designation: C 604 02 (Reapproved 2007)Standard 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 case
2、 of revision, the year 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 truespecific gravity of solid materials, a
3、nd 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 determining true specific gravity.1.2 This standard does not purport to add
4、ress 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-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 128 Test Me
5、thod for Density, Relative Density (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 gasi
6、nto all pores. For practical purposes 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-cu
7、lated from the sample weight in 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. Fo
8、r purposes of illustration, the 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 pres
9、sure on each side of the differentialpressure 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 Bin
10、stead is moved only to position 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
11、in both cylinders are equal, will 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 rati
12、o of itstrue density, determined 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
13、hydratablematerials which are not 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 likesamples, indicating mineralogical phases or phas
14、e 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 researchand development. It can
15、also serve as a referee test method inpurchasing contracts or agreements.4.5 Fundamental assumptions inherent in this test methodare the following:1This test method is under the jurisdiction of ASTM Committee C08 onRefractories and is the direct responsibility of Subcommittee C08.03 on PhysicalPrope
16、rties.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 ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
17、s 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.4.5.1 The sample is representative of the material in general,4.5.2 The total sample has been reduc
18、ed to the particle sizespecified,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 met
19、hod has been conducted in a meticulousmanner.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 13
20、5. Even thisfiner particle size 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 approximati
21、ons ratherthan accurate representations 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
22、. Apparatus5.1 Analytical Balance, 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 wi
23、thout contamination.5.6 Gas-Comparison 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 grindi
24、ng, ignite the total sample at 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 ignitio
25、n, place the powdered sample in 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
26、 desiccator and rapidlyfill the 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 thesample is removed from the desiccator the succeeding stepsmust be taken as rapidly as possible to preve
27、nt hydration.7.3 Place the sample cup with sample in the pycnometersample compartment and lock firmly into place. Purge thepycnometer 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
28、 atmosphere volume3A suitable instrument is the Beckman Air Comparison Pycnometer manufac-tured by Beckman Instruments, Inc., 2500 Harbor Blvd., Fullerton, CA 92634.FIG. 1 Simplified Schematic DiagramC 604 02 (2007)2measurement except that the wait period for temperatureequilibration is increased to
29、 60 s.7.5 Repeat the volume measurement 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 =
30、 true specific gravity,W = sample 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. P
31、recision and Bias10.1 An interlaboratory 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 rang
32、ed from 3to 9 averaging 6. Replicates 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 f
33、or the4th lab was not identified. 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 g
34、iven below inthe unit of measurement (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 t
35、he applicable 95 % limit, itcannot 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
36、 limit and reproducibilitylimit) 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 spe
37、cificgravity because no reference 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 mentio
38、nedin 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 committee an
39、d 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 meeting o
40、f 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 Drive, PO Box
41、 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).4Details are given in a research report available from ASTM InternationalHeadquarters. Request RR:C081013.C 604 02 (2007)3
