GOST 15027.15-83
GOST 15027.15−83 Bronze without tin. Methods for determination of cobalt (with Change No. 1)
GOST 15027.15−83
Group В64*
_____________________
* In the Index «National standards», 2004
a Group is specified B59. — Note the CODE.
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods for determination of cobalt
Non-tin bronze.
Methods for the determination of cobalt
AXTU 1709
Date of introduction 1983−07−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee for standards from
3. INTRODUCED FOR THE FIRST TIME
4. The standard fully complies ST SEV 1537−79
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | The number of the paragraph, subparagraph |
| GOST 199−78 |
2.2 |
| GOST 123−98 |
2.2, 3.2 |
| GOST 3118−77 |
3.2 |
| GOST 4204−77 |
2.2 |
| GOST 4461−77 |
2.2, 3.2 |
| GOST 6563−75 |
2.2 |
| GOST 15027.1−77 |
1.1, 2.2 |
| GOST 25086−87 |
1.1, 2.4.4, 3.4.4 |
| THAT 6−09−07−1582−87 |
2.2 |
6. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
7. EDITION with Change No. 1, approved in March 1988 (ICS 6−88)
This standard sets the photometric and atomic absorption methods for the determination of cobalt (at a mass fraction of cobalt from 0.01% to 0.6%) in the bronze without tin.
The standard fully conforms to the standard of the CMEA 1537−79.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 with the addition of sec. 1 GOST 15027.1.
(Changed edition, Rev. N 1).
2. PHOTOMETRIC METHOD
2.1. The essence of the method
The method is based on the formation of cobalt with nitroso-R-salt colored complex compound and measuring the optical density of the resulting solution.
2.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Electrolysis setup with a platinum mesh electrode according to GOST 6563.
Nitric acid according to GOST 4461 and diluted 1:1.
Sulfuric acid according to GOST 4204.
A mixture of acids: 30 cmof sulphuric acid is gradually poured in 75 cm
of water, the solution is cooled and added 20 cm
of nitric acid.
Sodium acetate according to GOST 199, a solution of 500 g/DM; stored in a dark vessel.
Cobalt GOST 123 with a mass fraction of cobalt not less than 99.9%.
Standard solutions of cobalt.
Solution a: 0.1 g of cobalt dissolved in 10 cmof nitric acid and nitrogen oxides is removed by boiling. The solution is transferred into a measuring flask with volume capacity of 1000 cm
, made up to the mark with water and mix.
1 cmof the solution contains 0.0001 g of cobalt.
Solution B: 25 cmsolution And placed in a volumetric flask with a capacity of 250 cm
, made up to the mark with water and mix.
1 cmof solution B contains 0,00001 g of cobalt.
Nitroso-R-salt on the other 6−09−07−1582, a solution of 4 g/DM(stored in a vessel made of dark glass).
(Changed edition, Rev.
N 1).
2.3. Analysis
2.3.1. A portion of the alloy mass, given in table.1, is placed in a beaker with a capacity of 250 cm, and dissolved in 30 cm
of the mixture of acids first without heating and then with heating. After dissolution of the sample, the nitrogen oxides are removed by boiling.
Table 1
| Mass fraction of cobalt, % | The mass of charge, g | The volume aliquote part of the solution, cm |
| From 0.01 to 0.10 |
2,5 | 10 |
| SV. 0,10 «0,4 |
0,5 | 10 |
| «0,4» 0,6 |
0,6 | 5 |
The solution is diluted with water to a volume of 150 cmand produce copper by electrolysis according to GOST 15027.1. The electrolyte transferred to a volumetric flask with a capacity of 250 cm
, made up to the mark and mix.
If necessary the solution was filtered.
Depending on the mass fraction of cobalt in bronze aliquote take part in accordance with the table.1. Aliquot part of the solution is placed in two glasses with a capacity of 100 cm. In the first beaker was added 10 cm
of a solution of sodium acetate, 5 cm
solution, nitroso-R-salt and boil for 1−2 minutes, then add 10 cm
of nitric acid (1:1) and again boil for 1−2 min.
The second beaker was added 10 cmof nitric acid (1:1), boil 1−2 min, then add 5 cm
of the solution, nitroso-R-salt, 10 cm
of a solution of sodium acetate and boil again.
The solutions were cooled, transferred to volumetric flasks with a capacity of 50 cm, made up to the mark with water and mix. After 20 minutes, measure the optical density on the spectrophotometer at a wavelength of 520 nm in a cuvette of 1 cm or photoelectrocolorimeter with a green filter at
=490 nm.
Solution comparison is the solution from the second flask.
The content of cobalt is calculated using a calibration graph
the IR.
2.3.2. Construction of calibration curve
In six of the seven glasses with a capacity of 100 cmis introduced 1,0; 2,0; 4,0; 6,0; 8,0 and 10,0 cm
standard solution B of cobalt. In all the glasses added to 10 cm
of a solution of sodium acetate and 5 cm
of the solution, nitroso-R-salt. The solutions were boiled for 1−2 min. Add 10 cm
of nitric acid (1:1) and again boil for 1−2 min. the Solutions were cooled and transferred to volumetric flasks with a capacity of 50 cm
, made up to the mark with water, mix and after 20 min, measure the optical density as indicated in claim
2.4. Processing of the results
2.4.1. Mass fraction of cobalt () in percent is calculated by the formula
where is the mass of cobalt was found in the calibration schedule g;
— the weight of the portion corresponding to aliquote part of the solution,
2.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
Table 2
| Mass fraction of cobalt, % |
|
|
| From 0.01 to 0.025 incl. |
0,002 | 0,005 |
| SV. 0,025 «0,050 |
0,003 | 0,007 |
| «0,05» 0,10 |
0,005 | 0,01 |
| «To 0.10» to 0.25 |
0,010 | 0,02 |
| «0,25» 0,50 |
0,015 | 0,04 |
| «Of 0.50» to 0.60 |
0,020 | 0,05 |
(Changed edition, Rev. N 1).
2.4.3. The absolute discrepancies of the analysis results 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 given in table.2.
2.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is performed by comparison of the results obtained photometric and atomic absorption methods or by a method of additives in accordance with GOST 25086.
2.4.3,
3. ATOMIC ABSORPTION METHOD
3.1. The essence of the method
The method is based on measuring the absorption of light by atoms of cobalt formed during the introduction of the analyzed solution in the flame acetylene-air.
3.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for cobalt.
Nitric acid according to GOST 4461 diluted 1:1 and 2 mol/DMsolution.
Hydrochloric acid according to GOST 3118, 2 mol/DMsolution.
Cobalt GOST 123 with a mass fraction of cobalt not less than 99.9%.
Standard solutions of cobalt.
Solution a: 0.5 g of cobalt is dissolved by heating in 10 cmof nitric acid (1:1), the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm
and top up with water to the mark.
1 cmof the solution contains 0.0005 g of cobalt.
Solution B: 20 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, add 10 cm
of 2 mol/DM
hydrochloric acid solution and add water to the mark.
1 cmof a solution contains 0.0001 g Koba
it.
3.3. Analysis
3.3.1. A portion of the alloy mass, given in table.3, is placed in a beaker with a capacity of 250 cmand dissolved by heating in 10 cm
of nitric acid (1:1). The solution was cooled, transferred to an appropriate volumetric flask (see table 3) and top up with water to the mark.
Table 3
| Mass fraction of cobalt, % |
The mass of charge, g | The volume of the final sample solution, cm |
| From 0.01 to 0.20 |
1 | 100 |
| SV. 0,20 «0,6 |
0,5 | 250 |
Measure the atomic absorption of cobalt in the flame acetylene-air at a wavelength of 240,7 nm parallel to the calibration solutions.
3.3.2. Construction of calibration curve
In nine out of ten volumetric flasks with a capacity of 100 cmis placed 0,5; 1,0; 2,5; 5,0 and 7,5 cm
standard solution and 2,0; 3,0; 4,0 and 5,0 cm
standard solution And cobalt.
To all flasks add 10 cmof 2 mol/DM
nitric acid and add water to the mark. Measure the atomic absorption of cobalt as described in section
3.4. Processing of the results
3.4.1. Mass fraction of cobalt () in percent is calculated by the formula
where is the concentration of cobalt was found in the calibration schedule, g/cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion,
3.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 1).
3.4.3. The absolute discrepancies of the analysis results 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 given in table.2
3.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is performed by comparison of results obtained by atomic absorption and photometric methods in accordance with GOST 25086.
3.4.3,
