GOST 15027.19-86
GOST 15027.19−86 Bronze without tin. Methods for determination of tellurium (with Change No. 1)
GOST 15027.19−86
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods for determination of tellurium
Tinless bronze.
Methods for determination of tellurium
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 859−2001 |
2.2 |
| GOST 3118−77 |
2.2 |
| GOST 4204−77 |
3.2 |
| GOST 4208−72 |
3.2 |
| GOST 4220−75 |
3.2 |
| GOST 4461−77 |
2.2; 3.2 |
| GOST 5457−75 |
2.2; 3.2 |
| GOST 6691−77 |
3.2 |
| GOST 17614−80 |
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 of the USSR from
6. EDITION with Change No. 1, approved in October 1991 (IUS 1−92)
This standard establishes the atomic absorption and potentiometric methods for the determination of tellurium (if the mass fraction of tellurium from 0.2% to 1.0%) in tin bronze according to GOST 18175.
The standard fully complies ST SEV 5009−85.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 when two parallel definitions.
2. ATOMIC ABSORPTION METHOD
2.1. The essence of the method
The method is based on dissolving the samples in nitric acid and the change of the atomic absorption of tellurium in the flame acetylene-air at a wavelength of 214,3 nm.
2.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with all accessories.
A radiation source for tellurium.
Acetylene according to GOST 5457.
Nitric acid according to GOST 4461, diluted 1:1 and 2:1.
Hydrochloric acid according to GOST 3118, 1 mole/DMsolution.
Copper of mark M0 GOST 859.
Standard copper solution: 5 g of copper is dissolved in 50 cmof nitric acid (1:1), boil to remove oxides of nitrogen. The solution was then cooled, placed in a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof the solution contains 0.05 g of copper.
Tellurium GOST 17614.
A standard solution of tellurium: 0.5 g of tellurium are dissolved in a water bath 10 cmof nitric acid (2:1) and evaporated to a moist residue. The residue is dissolved in 1 mol/DM
hydrochloric acid, the solution transferred to 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 tellurium
.
2.3. Analysis
2.3.1. Weighed samples weighing 0.5 g were placed in a glass with a capacity of 250 cm, adding 10 cm
of nitric acid (1:1) and dissolved by heating. The solution was boiled to remove oxides of nitrogen, cooled, diluted with water to 30 cm
, transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix. Measure the atomic absorption of tellurium in the flame acetylene-air at a wavelength of 214,3 nm parallel to the sample solution, the solution control experience and solutions to build the calibration curve. The concentration of tellurium find for the calibration schedule.
2.3.2. Construction of calibration curve
In six volumetric flasks with a capacity of 100 cmplaced at 10 cm
of a solution of copper; in five of them add 1,0; 2,0; 3,0; 4,0 and 5,0 cm
standard solution of tellurium, which corresponds to the 1,0; 2,0; 3,0; 4,0 and 5,0 mg of tellurium. All the bottles topped up to the mark with water and mix. Measure the atomic absorption of tellurium immediately before and after measuring the absorbance of the sample solution. According to the obtained values build the calibration graph.
2.4. Processing of the results
2.4.1. The content of tellurium () in percent is calculated by the formula
where is the concentration of tellurium in the sample solution found by the calibration schedule, g/cm
;
— the concentration of tellurium in solution in the reference experiment, was found in the calibration schedule, g/cm
;
— the volume of the sample solution, cm
;
— weight of sample, g
.
2.4.2. Discrepancies in the results of parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence) specified in the table.
(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 given in the table.
| Mass fraction of tellurium, % |
|
|
| From 0.2 to 0.5 incl. |
0,03 | 0,04 |
| SV. 0,5 «1,0 « |
0,05 | 0,07 |
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 of the bronzes, the determination of tellurium is carried out by atomic absorption method.
3. POTENTIOMETRIC METHOD
3.1. The essence of the method
The method is based on dissolving the sample in nitric acid, the oxidation of tellurium (IV) is titrated with a solution of potassium dichromate to the tellurium (VI) and the titration of its excess of salt solution Mora.
3.2. Apparatus, reagents and solutions
The setup for potentiometric titration with a saturated calomel electrode and a platinum indicator electrode.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 4204, diluted 1:1.
Urea according to GOST 6691.
Potassium dichromate according to GOST 4220.
0,017 mol/DMsolution: 2,4517 g of potassium dichromate, previously dried at 150 °C to constant weight, dissolved in water, transferred to a measuring flask with volume capacity of 1000 cm
, made up to the mark with water and mix.
1 cmof the mortar is 0,00319 g of tellurium.
Allowed the use of the solution preparation of fiksanala.
Salt of protoxide of iron and ammonium double sulfate (salt Mora) according to GOST 4208, 0.05 mol/DMsolution: 19,6 g of Mohr salt dissolved in 800 cm
of water containing 60 cm
of sulfuric acid solution, cooled, transferred into a measuring flask with volume capacity of 1000 cm
, made up to the mark with water and mix.
The conversion factor for a solution of salt Mora set in the following way: 20 cmsolution of potassium dichromate is placed in a beaker with a capacity of 600 cm
, added 40 cm
of sulfuric acid solution, dilute with water to volume of 200 cm
and potentiometric titrated with a solution of salt Mora to jump in the potential.
The conversion factor for a solution of salt Mora () is calculated by the formula
where is the volume of potassium dichromate solution taken for titration, cm
;
— the volume of salt solution Mora, used for titration, sm
.
3.3. Analysis
Weighed samples weighing 5 g were placed in a glass with a capacity of 400 cm, was added 40 cm
of nitric acid solution and dissolved first in cold and then when heated. After dissolving, the solution was boiled to remove oxides of nitrogen, cool, add 1 g of urea, dilute with water to volume of 200 cm
and mixed. Then add 40 cm
of sulfuric acid solution, cooled and while stirring, add 20 cm
of a solution of potassium dichromate. The solution is kept for 15 min. the Excess solution of potassium dichromate potentiometric titrated with a solution of salt Mora to jump in the potential.
3.4. Processing of the results
3.4.1. Mass fraction of tellurium () in percent is calculated by the formula
where is the volume of solution of potassium dichromate taken for the oxidation of tellurium, cm
;
— the volume of salt solution Mora, used for titration of excess of solution of potassium dichromate, cm
;
— the conversion factor for a solution of salt Mora;
0,00319 — weight of tellurium, corresponding to 1 cmof potassium dichromate solution;
— weight of sample, g
.
3.4.2. Discrepancies in the results of parallel definitions should not exceed the values omit differences (
the rate of convergence) specified in the table.
(Changed edition, Rev. N 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 given in the table.
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,
