ASTM C958-92(1997)e1

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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e1
Designation: C 958 – 92 (Reapproved 1997)
Standard Test Method for
Particle Size Distribution of Alumina or Quartz by X-Ray
Monitoring of Gravity Sedimentation
This standard is issued under the fixed designation C 958; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Editorial changes were made in Section 10 in October 1997.
1. Scope X-ray beam passing through the sedimenting dispersion to a
detector. The specimen concentration at any given sedimenta-
1.1 This test method covers the determination of the particle
tion distance is inversely proportional to the X-ray flux and the
size distribution of alumina or quartz powders in the range
equivalent diameter (spherical) is calculated from Stokes’ law.
from 0.5 to 50 μm and having a median particle diameter from
2.5 to 10 μm using a sedimentation method. This test method
NOTE 1—Refer to Terminology C 242. Most equipment manufacturers
is one of several found valuable for the measurement of
refer to this as the equivalent spherical diameter.
particle size. Instruments used for this test method employ a
5. Apparatus
constant intensity X-ray beam that is passed through a sedi-
menting dispersion of particles. 5.1 X-Ray Sedimentation Apparatus.
5.2 Ultrasonic Probe or Bath—An ultrasonic probe ap-
1.2 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information proximately 13-mm ( ⁄2-in.) in diameter and approximately 50
to 100 W or an ultrasonic bath of approximately 0.3 W/cm (2
only.
1.3 This standard does not purport to address all of the W/in. ).
safety concerns, if any, associated with its use. It is the
6. Reagents
responsibility of the user of this standard to establish appro-
6.1 Purity of Reagents—Reagent grade chemicals shall be
priate safety and health practices and determine the applica-
used in all tests. Unless otherwise indicated, it is intended that
bility of regulatory limitations prior to use. For specific hazard
all reagents shall conform to the specifications of the Commit-
statements, see Section 7.
tee on Analytical Reagents of the American Chemical Society,
2. Referenced Documents
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
2.1 ASTM Standards:
C 242 Terminology of Ceramic Whitewares and Related sufficiently high purity to permit its use without lessening the
accuracy of the determination.
Products
E 177 Practice for Use of the Terms Precision and Bias in 6.2 Distilled or Deionized Water.
6.3 Dispersing Liquid—Dissolve 1.0 g/L of reagent grade
ASTM Test Methods
E 691 Practice for Conducting an Interlaboratory Study to sodium hexametaphosphate in distilled or deionized water.
Determine the Precision of a Test Method Discard any remaining solution after six weeks from date of
preparation.
3. Terminology
7. Hazards
3.1 For definitions of terms used in this test method, refer to
7.1 Precautions applying to the use of low-intensity X-rays
Terminology C 242.
should be observed.
4. Summary of Test Method
7.2 Users should be aware that sample concentrations used
4.1 An aqueous homogeneous dispersion of the specimen is in this test method may be higher than those considered ideal
permitted to settle in a cell. The decrease in particle concen-
tration over a programmed settling distance is monitored by an
Instruments available from Quantachrome Corp., 5 Aerial Way, Syosset, NY
11791, and Micromeritics Instrument Corp., One Micromeritics Drive, Norcross,
GA 30093, have been found satisfactory for this purpose.
1 5
This test method is under the jurisdiction of ASTM Committee C21 on Ceramic Reagent Chemicals, American Chemical Society Specifications, American
Whitewares and Related Productsand is the direct responsibility of Subcommittee Chemical Society, Washington, DC. For suggestions on the testing of reagents not
C21.04on Clays. listed by the American Chemical Society, see Analar Standards for Laboratory
Current edition approved Aug. 15, 1992. Published December 1992. Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Annual Book of ASTM Standards, Vol 15.02. and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
Annual Book of ASTM Standards, Vol 14.02. MD.
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C 958
by some authorities and that the range of this test method 8.7.1 It is recommended that 8.6 and 8.7
...