ASTM C760-90(2007)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C760 − 90 (Reapproved2007)
Standard Test Methods for
Chemical and Spectrochemical Analysis of Nuclear-Grade
Silver-Indium-Cadmium Alloys
This standard is issued under the fixed designation C760; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 Other Document:
NBS Circular 602
1.1 These test methods cover procedures for the chemical
and spectrochemical analysis of nuclear grade silver-indium-
3. Significance and Use
cadmium (Ag-In-Cd) alloys to determine compliance with
3.1 Silver-indium-cadmium alloy is used as a control mate-
specifications.
rial in nuclear reactors. In order to be suitable for this purpose,
1.2 Theanalyticalproceduresappearinthefollowingorder:
the material must meet the specifications for assay and impu-
Sections rity content. These test methods are designed to show whether
Silver, Indium, and Cadmium by a Titration Method 7-15
or not a given material meets the specifications as given in
Trace Impurities by Carrier-Distillation Spectro- 16-22
Specification C752.
chemical Method
3.1.1 An assay is performed to determine whether the
1.3 The values stated in SI units are to be regarded as the
material has the chemical composition specified.
standard.
3.1.2 The impurity content is determined to ensure that the
maximum concentration limit of impurities is not exceeded.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Purity of Reagents
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.1 Reagent grade chemicals shall be used in all tests.
bility of regulatory limitations prior to use. For specific hazard
Unlessotherwiseindicated,itisintendedthatallreagentsshall
and precautionary statements, see Section 5 and Practices E50.
conform to the specifications of the Committee on Analytical
Reagents of the American Chemical Society, where such
2. Referenced Documents specifications are available. Other grades may be used, pro-
vided it is first ascertained that the reagent is of sufficiently
2.1 ASTM Standards:
high purity to permit its use without lessening the accuracy of
C752 Specification for Nuclear-Grade Silver-Indium-
the determination.
Cadmium Alloy
4.2 Purity of Water—Unless otherwise indicated, references
D1193Specification for Reagent Water
towatershallbeunderstoodtomeanreagentwaterconforming
E50Practices for Apparatus, Reagents, and Safety Consid-
to Specification D1193.
erations for Chemical Analysis of Metals, Ores, and
Related Materials
5. Hazards
E115Practice for Photographic Processing in Optical Emis-
sion Spectrographic Analysis (Withdrawn 2002)
5.1 Properprecautionsshouldbetakentopreventinhalation
or ingestion of heavy element (silver, indium, or cadmium)
powder or dust during handling.
These test methods are under the jurisdiction of ASTM Committee C26 on
5.2 Workers should observe precautions as specified in
Nuclear Fuel Cycle and are the direct responsibility of Subcommittee C26.03 on
vendor-supplied Material Safety Data Sheets (MSDS).
Neutron Absorber Materials Specifications.
Current edition approved July 1, 2007. Published August 2007. Originally
approved in 1971. Last previous edition approved in 2002 as C760–90(2002).
DOI: 10.1520/C0760-90R07. Available from National Institute of Standards and Technology (NIST), 100
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Reagent Chemicals, American Chemical Society Specifications, American
Standards volume information, refer to the standard’s Document Summary page on Chemical Society, Washington, DC. For suggestions on the testing of reagents not
the ASTM website. listed by the American Chemical Society, see Analar Standards for Laboratory
The last approved version of this historical standard is referenced on Chemicals,BDHLtd.,Poole,Dorset,U.K.andthe United States Pharmacopeia and
www.astm.org. National Formulary,U.S.PharmacopeialConvention,Inc.(USPC),Rockville,MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C760 − 90 (2007)
6. Sampling EDTAintoasmallplasticbeaker.Dissolvewithwater,transfer
quantitativelytoa1-Lvolumetricflask,andmakeuptovolume
6.1 Suggestions for sampling this alloy are given in Speci-
with water.Transfer the solution to a plastic storage bottle. Do
fication C752.
not allow the EDTA solution to stand in contact with glass
containers.
SILVER, INDIUM, AND CADMIUM BY A TITRATION
METHOD
11.5 Indium (In)—Metal, >99.99% pure.
11.6 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
7. Scope
(HNO ).
7.1 This test method is applicable to the determination of
11.7 PAN Indicator Solution (0.1% PAN in Methanol)—
silver, indium, and cadmium in alloys of approximately 80%
Dissolve 100 mg of 1-(2-pyridylazo)-2-naphthol in 100 mLof
silver, 15% indium, and 5% cadmium used in nuclear reactor
6,7
methyl alcohol and mix until completely dissolved.
control rod applications. The titrimetric methods presented
will yield results with a bias of the order of 0.1%.
11.8 Silver (Ag)—Metal, >99.99% pure.
11.9 Sodium Chloride (NaCl).
8. Summary of Test Method
11.10 Sodium Chloride Solution (0.0500 M)—Dry sodium
8.1 Aweighed sample is dissolved in nitric acid and diluted
chloride (NaCl) at 120°C, in a weighing bottle, to a constant
to a known volume, and aliquots are removed for analysis.
weight and cool to room temperature in a desiccator. Weigh
Silver is determined first by titrating with standardized sodium
2.922 6 0.001 g of the dried NaCl into a small plastic beaker.
chloride solution to the potentiometric endpoint indicated by a
Dissolve in water, quantitatively transfer to a 1-L volumetric
chloride-selective ion electrode. Following the silver titration,
flask, and make up to volume with water.
the solution is boiled to coagulate the silver chloride. The pH
isadjustedto2.5andtheindiumcontentistitratedwithEDTA,
12. Standardization
using PAN (1-(2-pyridylazo)-2-naphthol) indicator. The pH is
thenraisedto6.0andthecadmiumistitratedwithEDTAusing
12.1 Silver-Indium-Cadmium Calibration Standard:
the same indicator. The entire process requires approximately
12.1.1 Clean approximately 8.0 g of silver metal, 1.5 g of
20 min per aliquot, exclusive of sample weighing and disso-
indium metal, and 0.5 g of cadmium metal with an organic
lution.
solvent and air dry.
12.1.2 Weigh each metal accurately and transfer to a
9. Interferences
100-mL beaker.
9.1 Nointerferenceshavebeenobservedfromanyelements
12.1.3 Add sufficient water to cover the metal pieces and
normally encountered as impurities in nuclear grade silver-
add HNO (sp gr 1.42) dropwise until dissolution is complete.
indium-cadmiumalloyovertheconcentrationrangesexpected.
12.1.4 Transfer quantitatively to a 100-mLvolumetric flask
and dilute to volume with water.
10. Apparatus
12.2 Calibration of NaCl and EDTA Titrants:
10.1 Burets, precision, two, 25-mL capacity, preferably
12.2.1 Pipet 10 mL of the calibration standard into a
Schellbach type with TFE-fluorocarbon stopcock and auto-
100-mL volumetric flask and dilute to volume with water.
matic zero. They shall be certified or tested to conform with
(Retain this solution as a working standard.)
tolerances specified in NBS Circular 602.
12.2.2 Pipet 10 mL of the diluted standard into a 100-mL
10.2 Reference Electrode—Saturated calomel electrode.
beaker and adjust the volume to about 25 mL with water.
12.2.3 Adjust the pH to approximately 1 using NH OH (sp
10.3 Glass pH Electrode—Standard type.
gr 0.90).
10.4 Chloride Specific Ion Electrode.
12.2.4 Place a TFE-fluorocarbon-coated stirring bar in the
10.5 Expanded Scale pH/millivolt Meter. solution and insert the chloride specific ion electrode and the
reference electrode.
11. Reagents
12.2.5 StiratamoderaterateandtitratethesilverwithNaCl
solution. Record millivolt readings versus volume added.
11.1 Ammonium Hydroxide (sp gr 0.90)—Concentrated am-
Allow sufficient time for equilibrium readings to be attained.
monium hydroxide (NH OH).
12.2.6 The titration end point is taken as the termination of
11.2 Buffer Solution, pH4—0.5 M sodium acetate—0.5 M
the rapidly rising segment of the millivolt versus volume
acetic acid.
titration curve.
11.3 Cadmium (Cd)—Metal, >99.99% pure.
12.2.7 Adjust to pH 2.5 6 0.2 by dropwise addition of
acetate buffer solution (pH4).
11.4 Ethylenediaminetetraacetate Dihydrate Disodium Salt
12.2.8 Remove the electrodes and rinse thoroughly to avoid
(EDTA) Solution (0.01000 M)—Weigh 3.722 6 0.001 g of
loss of indium and cadmium.
12.2.9 Heat the solution to boiling on a hotplate until the
Cheng, K. L., “Complexometric Titration of Indium,” Analytical Chemistry,
supernatant liquid is clear. Allow to cool.
Vol 27, 1955, p. 1582.
12.2.10 Add4dropsofPANindicatorsolution.Thesolution
Cheng, K. L., “Complexometric Titration of Copper and Other Metals in a
Mixture,” Analytical Chemistry, Vol 30, 1958, p. 243. should be deep purple.
C760 − 90 (2007)
12.2.11 Titrate the indium with standard EDTA solution to TRACE IMPURITIES BY
the sharp transition from purple to yellow. The volume used CARRIER–DISTILLATION
corresponds to the indium content. SPECTROCHEMICAL METHOD
12.2.12 AdjusttopH6 60.2withNH OH(spgr0.90).The
16. Scope
color of the solution will change back to purple.
12.2.13 TitratethepurplesolutionwithstandardEDTAuntil 16.1 This test method is applicable to the determ
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