GOST 16321.1-70
GOST 16321.1−70 Silver-copper alloys. Method for determination of silver content (with Amendments No. 1, 2)
GOST 16321.1−70*
Group B59
STATE STANDARD OF THE USSR
SILVER-COPPER ALLOYS
Method for determination of silver content
Silver-copper alloys. Method for determination of silver content
AXTU 1709
Date of introduction 1972−01−01
Resolution of the Committee of standards, measures and measuring devices under Council of Ministers of the USSR from 26. VIII 1970 N 1328 the date of the entry is set with 01.01.72
Proven in 1985 by the Resolution of Gosstandart from
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** Expiration removed by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (I & C N 11/12, 1994). — Note the manufacturer’s database.
REPLACE GOST 7979−56 in part of sec. II
* REVISED (July 1986) with Amendments No. 1, 2 approved in August 1980, February 1985 (IUS 10−80, 5−85).
This standard applies to silver-copper alloys and sets the potentiometric method for the determination of silver (at a mass fraction of silver from 49.5 to 97.3%).
The method is based on potentiometric titration of silver ion with a sodium chloride solution with the use of automatic titration unit. As the reference electrode used silver chloride electrode, filled with saturated solution of potassium nitrate. The indicator electrode is a silver wire.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 22864−83.
2. APPARATUS, REAGENTS AND SOLUTIONS
Nitric acid GOST 4461−77 and diluted 1:1.
Silver GOST 6836−80* brands of SR 999,9.
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* On the territory of the Russian Federation GOST 6836−2002. — Note the manufacturer’s database.
Laboratory pH-meter-millivoltmeter.
The magnetic stirrer.
Burette with automatic zero setting capacity of 50 cm.
The block automatic titration laboratory.
Sodium chloride, 0.1 N. solution; prepared from fixanal 0.1 g·EQ. In the absence of fiksanala dissolved in water 5,85 g of sodium chloride according to GOST 4233−77 and bring the volume to 1 DMwith water.
Titer of 0.1 n sodium chloride solution set as follows: a portion of silver is 0.45 g (take three parallel sample) were placed in a glass with a capacity of 250 cm, was dissolved with heating in 10 cm
of nitric acid, diluted 1:1, heated to remove oxides of nitrogen and dilute with water to 100 cm
. The solution was titrated as described in sec. 4.
3. PREPARATION FOR ASSAY
A suspension of 0.5 g (take three parallel sample) were placed in a glass with a capacity of 250 cm, is dissolved when heated in nitric acid, diluted 1:1. The solution is heated to remove oxides of nitrogen and diluted with water to about 100 cm
.
(Changed edition, Rev. N 2).
4. ANALYSIS
4.1. Prepared for the analysis of the solution is titrated potentiometric method of 0,1 n solution of sodium chloride to a predetermined potential difference on the block automatic titration.
(Changed edition, Rev. N 1).
5. CALCULATION OF RESULTS OF ANALYSIS
5.1. Mass fraction of silver () in percent is calculated by the formula
where — amount of 0.1 n sodium chloride solution consumed for titration, cm
;
the titer of a solution of sodium chloride of silver, g/cm
;
— hanging,
5.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level of 0.95 shall not exceed 0.10% when the mass fraction of silver from 49.5 to 80,0% and 0.15% when the mass fraction of silver of more than 80,0%.
(Changed edition, Rev. N 2).
