GOST 15027.17-86
GOST 15027.17−86 Bronze without tin. Methods for determination of silver (with Change No. 1)
GOST 15027.17−86
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods for determination of silver
Tinless bronze.
Methods for determination of silver
AXTU 1709
Date of introduction 1987−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. INTRODUCED FOR THE FIRST TIME
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | Section number, paragraph, sub-paragraph |
| GOST 3760−79 |
3.2 |
| GOST 4232−74 |
3.2 |
| GOST 4461−77 |
2.2, 3.2 |
| GOST 5457−75 |
2.2 |
| GOST 5817−77 |
3.2 |
| GOST 6836−80 |
2.2 |
| GOST 18175−78 |
Chapeau |
| GOST 25086−87 |
1.1; 2.4.2 b; 3.4.4 |
5. The expiration time limit is removed by the Resolution of Gosstandart from
6. EDITION with Change No. 1, approved in October 1991 (IUS 1−92)
This standard establishes the atomic absorption method for the determination of silver (at a mass fraction of silver from 0.02% to 2.5%) and a potentiometric method for the determination of silver (at a mass fraction of silver from 0.4% to 2.5%) in tin bronze according to GOST 18175.
The standard fully complies ST SEV 5006−85.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 when two parallel definitions.
2. ATOMIC ABSORPTION METHOD OF DETERMINING SILVER
2.1. The essence of the method
The method is based on dissolving the samples in nitric acid and measuring the atomic absorption of silver in the flame of acetylene-air at a wavelength of 328,1 nm.
2.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with all accessories.
A radiation source for silver.
Acetylene according to GOST 5457.
The water is tested for the absence of chloride ions (for the preparation of solutions and analysis).
Nitric acid according to GOST 4461, diluted 1:1 and 0.5 mol/DMsolution.
Silver GOST 6836.
Standard solutions of silver.
Solution a: 0.5 g silver is dissolved in 20 cmof nitric acid (1:1), cooled, placed in a volumetric flask with a capacity of 500 cm
, made up to the mark with water and mix.
1 cmof the solution contains 0.001 g of silver.
Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, add 10 cm
of 0.5 mol/DM
nitric acid, made up to the mark with water and mix.
1 cmof a solution contains 0.0001 g silver.
RA.
2.3. Analysis
2.3.1. Weighed samples weighing 0.5 g were placed in a glass with a capacity of 250 cm, add 20 cm
of nitric acid (1:1) and was dissolved first in cold and then when heated. After dissolving, the solution was boiled to remove oxides of nitrogen, cooled, transferred to a volumetric flask with a capacity of 100 or 250 cm
in accordance with table.1, made up to the mark with water and mix.
Table 1
| Mass fraction of silver, % | Capacity volumetric flasks, cm |
The volume aliquote part of the solution, cm |
| From 0.02 to 0.1 |
100 | The entire solution |
| SV. 0,1 «1,0 |
100 | 10 |
| «Of 1.0» to 2.5 |
250 | 10 |
When the mass fraction of silver than 0.1% in a volumetric flask with a capacity of 100 cmaliquote selected part of the sample solution according to table.1 add 10 cm
of 0.5 mol/DM
nitric acid, made up to the mark with water and mix.
Measure the atomic absorption of silver in parallel in the sample solution, the solution control experience and solutions to build a calibration curve at a wavelength of 328,1 nm in the flame acetylene-air.
The concentration of silver found by the calibration schedule.
2.3.2. Construction of calibration curve
In six of the seven volumetric flasks with a capacity of 100 cmplaced: 0,5; 1,0; 2,0; 3,0; 4,0 and 5.0 cm
standard solution B of silver, which corresponds to 0,05; 0,1; 0,2; 0,3; 0,4; 0,5 mg of silver. To all flasks add 10 cm
of 0.5 mol/DM
hydrochloric acid solution, made up to the mark with water and mix. Measure the atomic absorption of silver immediately before and after measuring the atomic absorption of the sample solution.
According to the obtained values build the calibration graph.
2.4. Processing of the results
2.4.1. Mass fraction of silver () in percent is calculated by the formula
where the silver concentration in the sample solution found by the calibration schedule, g/cm
;
the silver concentration in the solution in the reference experiment, was found in the calibration schedule, g/cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion of the sample or the weight of the portion corresponding to aliquote part of the sample solution, g
.
2.4.2. Discrepancies in the results of parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence) as shown in table.2.
(Changed edition, Rev. N 1).
2.4.2. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values specified in table.2.
Table 2
| Mass fraction of silver, % |
|
|
| From 0.02 to 0.05 incl. |
0,005 | 0,007 |
| SV. Of 0.05 «to 0.15 « |
0,01 | 0,014 |
| «To 0.15» to 0.3 « |
0,02 | 0,03 |
| «Of 0.3» to 1.0 « |
0,04 | 0,06 |
| «Of 1.0» to 2.5 « |
0,06 | 0,08 |
2.4.2 b. Control of accuracy of analysis results is carried out by additives or by comparison of the results obtained by the potentiometric method, in accordance with GOST 25086.
2.4.2 a, 2.4.2 b. (Added, Rev. N 1).
2.4.3. The differences in the assessment of the quality bronzes determination of silver is carried out by atomic absorption method.
3. POTENTIOMETRIC METHOD
3.1. The essence of the method
The method is based on dissolving the samples in nitric acid and potentiometric titration of a silver iodide of potassium in ammoniacal medium in the presence of tartaric acid.
3.2. Apparatus, reagents and solutions
The setup for potentiometric titration with a saturated calomel electrode and a silver indicator electrode.
The water is tested for the absence of chloride ions (for the preparation of solutions and analysis).
Nitric acid according to GOST 4461, diluted 1:1.
Tartaric acid according to GOST 5817, a solution of 500 g/DM.
Ammonia water according to GOST 3760, diluted 1:1.
Silver GOST 6836.
Standard silver solution: 0.25 g silver is dissolved in 10 cmof nitric acid removes nitrogen oxides by boiling, the solution was cooled, placed in a volumetric flask with a capacity of 250 cm
, made up to the mark with water and mix. 1 cm
standard solution contains 0.001 g of silver.
Potassium iodide according to GOST 4232, 0.05 M solution: 8.3 g of potassium iodide dissolved in water, the solution is placed in a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.
The installation of the mass concentration of the solution of potassium iodide: 50 cmstandard silver solution placed in a beaker with a capacity of 600 cm
, add 10 cm
of a solution of tartaric acid and dropwise with continuous stirring a solution of ammonia to obtain a pH of 8. the pH of the solution is controlled by universal indicator paper. The resulting solution is diluted with water to a volume of 300 cm
and potentiometric titrated with a solution of potassium iodide to spike potential.
The mass concentration of a solution of potassium iodide () in grams of silver per 1 cm
of a solution is calculated by the formula
where is the mass of silver in aliquote part of the solution, taken to establish mass concentration, g;
— the volume of potassium iodide solution consumed for titration, sm
.
(Changed edition, Rev. N 1).
3.3. Analysis
A portion of the sample weighing 2 g were placed in a glass with a capacity of 600 cm, add 20 cm
of a solution of nitric acid and dissolve in the cold and then when heated. After dissolving, the solution was boiled to remove oxides of nitrogen, cooled, diluted with water to a volume of 250 cm
, adding 10 cm
of a solution of tartaric acid and dropwise with continuous stirring a solution of ammonia to transition copper ammonium complex (avoid an excess of ammonia). The resulting solution is titrated by potentiometric solution of potassium iodide to spike potential.
3.4. Processing of the results
3.4.1. Mass fraction of silver () in percent is calculated by the formula
where is the volume of potassium iodide solution consumed for titration, cm
;
— mass concentration of a solution of potassium iodide, g/cm
;
— the weight of the portion of the sample,
3.4.2. Discrepancies in the results of parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence) as shown in table.2.
3.4.1,
3.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values specified in table.2.
3.4.4. Control of accuracy of analysis results is carried out by additives or by comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
3.4.3,
