GOST 16274.5-77

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  ГОСТ 16274.5-77

GOST 16274.5−77 Bismuth. Method for determination of silver content (with Amendments No. 1, 2, 3)

GOST 16274.5−77

Group B59

STATE STANDARD OF THE USSR

BISMUTH

Method for determination of silver content

Bismuth.
Method for determination of silver content

AXTU 1709

Date of introduction 1978−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

DEVELOPERS

PS Poklonsky, F. M. Manji, G. V. Khabarova

2. APPROVED AND promulgated by the DECREE of the State Committee of standards of Ministerial Council of the USSR from 25.01.77 N 172

3. The frequency of inspection 5 years

4. REPLACE GOST 16274.5−70

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Resolution of the state standard from 30.07.92 N 836 removed the limitation of the validity period

7. REPRINT (July 1997) with Amendments No. 1, 2, 3, approved in January 1983, June 1987, July 1992 (IUS 5−83, 11−87, 10−92)


This standard applies to metallic bismuth brands Vi1 and Vi2 and sets rodanistye volumetric method for determination of silver (with silver content from 0.1 to 0.5%).

The method is based on titration of silver with a solution of ammonium thiocyanate in acidic medium in the presence of bismuth. As an indicator used salesonline alum.

1. GENERAL REQUIREMENTS

General requirements for method of analysis according to GOST 16274.0.

2. GLASSWARE, REAGENTS AND SOLUTIONS

Volumetric flasks with a capacity of 1000 cmaccording to GOST 1770.

Microburette with a capacity of 2 cmin the NTD.

A pipette with a capacity of 25 cmin the NTD.

Heat-resistant conical flask with a capacity of 250 cmaccording to GOST 7851.

Distillation apparatus for producing the double-distilled water.

Nitric acid according to GOST 4461 chlorine-free and 1% solution.

Alum salesonline on the other 6−09−5359, 10% solution in 1% nitric acid solution.

Bismuth metal brand Ви0 according to GOST 10928.

Silver nitrate according to GOST 1277.

A standard solution of silver, prepared as follows: 15,7467 g of silver nitrate is placed in a measuring flask with volume capacity of 1000 cm, dissolved in bidistilled water, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of silver.

Bidistilled water.

Ammonium radamisty according to GOST 27067, solution with molar concentration 0,01 mol/DM.

The titer of the solution set in the following way: in six conical flasks with a capacity of 250 cmtaken at 25 cmstandard silver solution, is added to 2.5 g of bismuth brand Ви0 and dissolved in 50 cmof concentrated nitric acid, priliva small portions. The dissolution of lead first without heating and then heated to remove oxides of nitrogen. To the solution flow 100cmdouble-distilled water, cooled and titrated with a solution Rodenstock ammonium with molar concentration of 0,01 mol/DMin the presence of 2 cmgentoomaniac alum before the appearance of stable pink color.

The titer of the solution Rodenstock ammonium (), expressed in g/cmof silver, calculated by the formula

,

where  — amount of the standard solution taken for titration, cm;

0,01 — concentration of a standard solution of silver, g/cm;

 — number of Rodenstock ammonium solution with molar concentration 0,01 mol/DM, spent on titration, sm.

(Changed edition, Rev. N 2).

3. ANALYSIS

A sample of bismuth with a mass of 10.0 g is placed in a conical flask with a capacity of 250 cmand dissolved in 50 cmof concentrated nitric acid, priliva small portions. Dissolution of the sample is carried out at first without heating and then with heating to the disappearance of the oxides of nitrogen.

To the solution flow 100cmdouble-distilled water and, after cooling, titrated with a solution Rodenstock ammonium with molar concentration of 0,01 mol/DMin the presence of 2.0 cmgentoomaniac alum before the appearance of stable pink color.

(Changed edition, Rev. N 2).

4. PROCESSING OF THE RESULTS

4.1. The silver content in the bismuth () in percent is calculated by the formula

,

where the titer of a solution of ammonium thiocyanate, expressed in grams of silver per milliliter of solution;

 — the amount of a solution of ammonium thiocyanate consumed for titration, cm;

 — hanging,

4.2. The maximum discrepancy between the results of three parallel measurements () and the results of two tests () at a confidence probability of 0.95, should not exceed the values given in the table.

Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation or according to the formulas:

for the range of mass fraction from 0.1 to 0.3%;

for a mass fraction of more than 0.3%,

where is the arithmetic mean of results of three parallel measurements;

 — the arithmetic mean of the results of the two tests.

(Changed edition, Rev. N 3).