ASTM C760-90(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C760–90(Reapproved 2002)
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
1.1 These test methods cover procedures for the chemical 3.1 Silver-indium-cadmium alloy is used as a control mate-
and spectrochemical analysis of nuclear grade silver-indium- rial in nuclear reactors. In order to be suitable for this purpose,
cadmium (Ag-In-Cd) alloys to determine compliance with the material must meet the specifications for assay and impu-
specifications. rity content. These test methods are designed to show whether
1.2 Theanalyticalproceduresappearinthefollowingorder: or not a given material meets the specifications as given in
Specification C752.
Sections
Silver, Indium, and Cadmium by a Titration Method 7-15
3.1.1 An assay is performed to determine whether the
Trace Impurities by Carrier-Distillation Spectro- 16-22
material has the chemical composition specified.
chemical Method
3.1.2 The impurity content is determined to ensure that the
1.3 The values stated in SI units are to be regarded as the
maximum concentration limit of impurities is not exceeded.
standard.
1.4 This standard does not purport to address all of the 4. Purity of Reagents
safety concerns, if any, associated with its use. It is the
4.1 Reagent grade chemicals shall be used in all tests.
responsibility of the user of this standard to establish appro-
Unlessotherwiseindicated,itisintendedthatallreagentsshall
priate safety and health practices and determine the applica-
conform to the specifications of the Committee on Analytical
bility of regulatory limitations prior to use. For specific hazard
Reagents of the American Chemical Society, where such
andprecautionarystatements,seeSection5andPracticesE50.
specifications are available. Other grades may be used, pro-
vided it is first ascertained that the reagent is of sufficiently
2. Referenced Documents
high purity to permit its use without lessening the accuracy of
2.1 ASTM Standards:
the determination.
C 752 Specification for Nuclear-Grade Silver-
4.2 Purity of Water—Unlessotherwiseindicated,references
IndiumCadmium Alloy
towatershallbeunderstoodtomeanreagentwaterconforming
D1193 Specification for Reagent Water
to Specification D1193.
E50 Practices forApparatus, Reagents, and Safety Precau-
tions for Chemical Analysis of Metals 5. Hazards
E115 Practice for Photographic Processing in Optical
5.1 Properprecautionsshouldbetakentopreventinhalation
Emission Spectrographic Analysis
or ingestion of heavy element (silver, indium, or cadmium)
2.2 Other Document:
powder or dust during handling.
NBS Circular 602
5.2 Workers should observe precautions as specified in
vendor-supplied Material Safety Data Sheets (MSDS).
6. Sampling
These test methods are under the jurisdiction of ASTM Committee C26 on
6.1 Suggestions for sampling this alloy are given in Speci-
Nuclear Fuel Cycle and are the direct responsibility of Subcommittee C26.03 on
Neuron Absorber Materials. fication C752.
Current edition approved May 25, 1990. Published July 1990. Originally
published as C760–71. Last previous edition C760–79.
2 6
Annual Book of ASTM Standards, Vol 12.01. “ReagentChemicals,AmericanChemicalSocietySpecifications,”Am.Chemi-
Annual Book of ASTM Standards, Vol 11.01. calSoc.Washington,DC.Forsuggestionsonthetestingofreagentsnotlistedbythe
Annual Book of ASTM Standards, Vol 03.05. American Chemical Society, see “Reagent Chemicals and Standards,” by Joseph
Available from National Institute of Standards and Technology, Gaithersburg, Rosin, D. Van Nostrand Co., Inc., New York, NY, and the “United States
MD 20899. Pharmacopeia.”
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C760–90 (2002)
SILVER, INDIUM, AND CADMIUM BY A TITRATION 11.6 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
METHOD (HNO ).
11.7 PAN Indicator Solution (0.1% PAN in Methanol)—
7. Scope
Dissolve 100 mg of 1-(2-pyridylazo)-2-naphthol in 100 mLof
methyl alcohol and mix until completely dissolved.
7.1 This test method is applicable to the determination of
11.8 Silver (Ag)—Metal, >99.99% pure.
silver, indium, and cadmium in alloys of approximately 80%
silver, 15% indium, and 5% cadmium used in nuclear reactor 11.9 Sodium Chloride (NaCl).
,
11.10 Sodium Chloride Solution (0.0500 M)—Dry sodium
control rod applications. The titrimetric methods presented
will yield results with a bias of the order of 0.1%. chloride (NaCl) at 120°C, in a weighing bottle, to a constant
weight and cool to room temperature in a desiccator. Weigh
8. Summary of Test Method
2.922 6 0.001 g of the dried NaCl into a small plastic beaker.
Dissolve in water, quantitatively transfer to a 1-L volumetric
8.1 Aweighed sample is dissolved in nitric acid and diluted
flask, and make up to volume with water.
to a known volume, and aliquots are removed for analysis.
Silver is determined first by titrating with standardized sodium
12. Standardization
chloride solution to the potentiometric endpoint indicated by a
chloride-selective ion electrode. Following the silver titration,
12.1 Silver-Indium-Cadmium Calibration Standard:
the solution is boiled to coagulate the silver chloride. The pH
12.1.1 Clean approximately 8.0 g of silver metal, 1.5 g of
isadjustedto2.5andtheindiumcontentistitratedwithEDTA,
indium metal, and 0.5 g of cadmium metal with an organic
using PAN (1-(2-pyridylazo)-2-naphthol) indicator. The pH is
solvent and air dry.
thenraisedto6.0andthecadmiumistitratedwithEDTAusing
12.1.2 Weigh each metal accurately and transfer to a
the same indicator. The entire process requires approximately
100-mL beaker.
20 min per aliquot, exclusive of sample weighing and disso-
12.1.3 Add sufficient water to cover the metal pieces and
lution.
add HNO (sp gr 1.42) dropwise until dissolution is complete.
12.1.4 Transfer quantitatively to a 100-mLvolumetric flask
9. Interferences
and dilute to volume with water.
9.1 Nointerferenceshavebeenobservedfromanyelements
12.2 Calibration of NaCl and EDTA Titrants:
normally encountered as impurities in nuclear grade silver-
12.2.1 Pipet 10 mL of the calibration standard into a
indium-cadmiumalloyovertheconcentrationrangesexpected.
100-mL volumetric flask and dilute to volume with water.
(Retain this solution as a working standard.)
10. Apparatus
12.2.2 Pipet 10 mL of the diluted standard into a 100-mL
10.1 Burets, precision, two, 25-mL capacity, preferably
beaker and adjust the volume to about 25 mL with water.
Schellbach type with TFE-fluorocarbon stopcock and auto-
12.2.3 Adjust the pH to approximately 1 using NH OH (sp
matic zero. They shall be certified or tested to conform with
gr 0.90).
tolerances specified in NBS Circular 602.
12.2.4 Place a TFE-fluorocarbon-coated stirring bar in the
10.2 Reference Electrode—Saturated calomel electrode.
solution and insert the chloride specific ion electrode and the
10.3 Glass pH Electrode—Standard type.
reference electrode.
10.4 Chloride Specific Ion Electrode.
12.2.5 StiratamoderaterateandtitratethesilverwithNaCl
10.5 Expanded Scale pH/millivolt Meter.
solution. Record millivolt readings versus volume added.
Allow sufficient time for equilibrium readings to be attained.
11. Reagents
12.2.6 The titration end point is taken as the termination of
11.1 Ammonium Hydroxide(spgr0.90)—Concentratedam-
the rapidly rising segment of the millivolt versus volume
monium hydroxide (NH OH).
4 titration curve.
11.2 Buffer Solution, pH4—0.5 M sodium acetate—0.5 M
12.2.7 Adjust to pH 2.5 6 0.2 by dropwise addition of
acetic acid.
acetate buffer solution (pH4).
11.3 Cadmium (Cd)—Metal, >99.99% pure.
12.2.8 Remove the electrodes and rinse thoroughly to avoid
11.4 Ethylenediaminetetraacetate Dihydrate Disodium Salt
loss of indium and cadmium.
(EDTA) Solution (0.01000 M)—Weigh 3.722 6 0.001 g of
12.2.9 Heat the solution to boiling on a hotplate until the
EDTAintoasmallplasticbeaker.Dissolvewithwater,transfer
supernatant liquid is clear. Allow to cool.
quantitativelytoa1-Lvolumetricflask,andmakeuptovolume
12.2.10 Add4dropsofPANindicatorsolution.Thesolution
with water.Transfer the solution to a plastic storage bottle. Do
should be deep purple.
not allow the EDTA solution to stand in contact with glass
12.2.11 Titrate the indium with standard EDTA solution to
containers.
the sharp transition from purple to yellow. The volume used
11.5 Indium (In)—Metal, >99.99% pure.
corresponds to the indium content.
12.2.12 AdjusttopH6 60.2withNH OH(spgr0.90).The
color of the solution will change back to purple.
Cheng, K. L., “Complexometric Titration of Indium,” Analytical Chemistry,
12.2.13 TitratethepurplesolutionwithstandardEDTAuntil
Vol 27, 1955, p. 1582.
the color again changes to yellow. The volume used corre-
Cheng, K. L., “Complexometric Titration of Copper and Other Metals in a
Mixture,” Analytical Chemistry, Vol 30, 1958, p. 243. sponds to the cadmium content.
C760–90 (2002)
13. Procedure solution is added and mixed well. The slurry is evaporated to
dryness at 85 6 5°C in subdued light.
13.1 Clean approximately 1.0 g of the sample with an
17.2 The dried sample mixture is blended
...