ASTM B712-93(1999)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:B 712–93 (Reapproved 1999)
Standard Guide for
Determination of Sodium and Potassium Content For Silver-
Cadmium Oxide Contact Materials
This standard is issued under the fixed designation B 712; 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.
1. Scope methods of atomic absorption spectroscopy.The recommended
procedures cite methods for minimizing extraneous sodium
1.1 This guide describes procedures for use in conducting
and potassium contamination through use of specific handling
analysis of silver-cadmium oxide materials for sodium and
proceduresandshortersamplepreparationmethods.Thisguide
potassium content. The exact methods for the performance of
also recommends procedures that prevent the formation of
this testing are not stated since many different procedures are
nonstable and potentially hazardous silver-acetylene com-
equally applicable. This guide points out specific procedures
pounds.
for decreasing the chance of recognized potential errors and
specifies methods for increasing the sensitivity of the testing.
4. Precautions
1.2 This standard may involve hazardous materials, opera-
4.1 Since silver nitrate reacts with acetylene to form silver
tions, and equipment. This standard does not purport to
acetylide, the guide recommends either alternative flames to
address all of the safety problems associated with its use. It is
air–acetylene or the removal of silver from solution. Silver
the responsibility of whoever uses this standard to consult and
acetylide is unstable and may explode violently upon being
establish appropriate safety and health practices and deter-
disturbed.
mine the applicability of regulatory limitations prior to use.
For specific precautions see Sections 4 and 6.
5. Sampling
1.3 Whoever uses this standard should consult the Material
5.1 Handle the sample so as to avoid contamination by
Safety Data Sheet concerning the products involved.
sodium and potassium; avoid contact with hands.
2. Referenced Documents
6. Procedures
2.1 ASTM Standards:
6.1 First clean the sample in nitric acid and distilled or
E 50 Practices for Apparatus, Reagents, and Safety Precau-
deionized water to remove extraneous surface contamination.
tions for Chemical Analysis of Metals
3 Test powder samples as received. Then store the samples in
E 663 Practice for Flame Atomic Absorption Analysis
such a manner as to minimize contamination.
2.2 Other Document:
6.2 Use a sample size of approximately2gor more for each
Operation Guide for Chemical Analysis of Metals and
test.
Metal Bearing Ores by Atomic Absorption Spectropho-
4 6.3 Handle the samples with gloves and utensils, never with
tometry
bare hands.
3. Significance and Use 6.4 The use of TFE-fluorocarbon or other suitable substi-
tutesforglasswareisrecommended.Ifglassisused,agedglass
3.1 This guide is recommended for use in analyzing the
rather than new glass is recommended. Clean the glassware
sodium and potassium content of silver-cadmium oxide mate-
with ammonia and rinse with deionized water.Avoid the use of
rials and is meant to be used in conjunction with standard
detergents.
6.5 Calibrate the instrument and determine the optimum
This test method is under the jurisdiction of ASTM Committee B-2 on calibration-solution concentration in accordance with Practice
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
E 663 and other standards as
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