GOST 1293.12-83
GOST 1293.12−83 lead-antimony Alloys. Methods for determination of silver (with Amendments No. 1, 2)
GOST 1293.12−83
Group B59
STATE STANDARD OF THE USSR
LEAD-ANTIMONY ALLOYS
Methods for determination of silver
Lead-antimony alloys. Methods for the determination of silver
AXTU 1709*
________________
* Changed the wording, Rev. N 1.
Valid from 01.01.84
to 01.01.89*
_______________________________
* Expiration removed by Protocol No. 7−95
The interstate Council for standardization,
Metrology and certification (I & C N 11, 1995). -
Note the manufacturer’s database.
DEVELOPED by the Ministry of nonferrous metallurgy of the USSR
PERFORMERS
A. P. Sychev, M. G. Sun, L. I. Maksay, R. D. Kogan
INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
Member Of The Board Of A. P. Snurnikov
APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on standards of February 8, 1983 N 705
REPLACE GOST 1293.12−74
MADE: the Change in N 1, approved and put into effect by the Decree of the USSR State Committee for standards from
Change N 1, 2 made by the manufacturer of the database in the text IUS N 2, 1988, ICS # 7, 2001
This standard establishes the atomic absorption and photometric methods for determination of mass fraction of silver from 0.001 to 0.1% of lead-antimony alloys.
1. GENERAL REQUIREMENTS
General requirements for methods of analysis GOST 1293.0−83.
2. ATOMIC ABSORPTION METHOD
2.1. The essence of the method
The method is based on dissolving the alloy in a mixture of nitric and tartaric acids, the spraying solutions in the air-acetylene flame and measuring the absorption lines of silver 328,0 nm.
2.2. Apparatus, reagents and solutions
Atomic absorption spectrophotometer of any brand.
Air, compressed under a pressure of 2·10-6·10
PA (2−6 ATM), depending on equipment.
Acetylene in cylinders GOST 5457−75.
Nitric acid GOST 4461−77 and diluted 1:3.
Tartaric acid according to GOST 5817−77.
Silver GOST 6836−80*.
______________
* On the territory of the Russian Federation GOST 6836−2002. — Note the manufacturer’s database.
2.3. Preparation for assay
2 3.1. Preparation of standard solutions of silver
Solution a: 0,1000 g of silver dissolved in 10 cmof nitric acid solution under low heat, transferred to a volumetric flask with a capacity of 100 cm
, add 5 cm
of nitric acid and bring to mark with water.
1 cmof the solution contains 1 mg of silver.
Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm
, add 5 cm
of nitric acid was adjusted to the mark with water and mix.
1 cmof a solution contains 0.1 mg of silver.
Solution: 10 cmof a solution transferred to a volumetric flask with a capacity of 100 cm
, add 5 cm
of nitric acid was adjusted to the mark with water and mix.
1 cmof the solution contains 0.01 mg of silver.
(Changed edition, Rev. N 2).make 1, 2, 5 and 10 cm
standard solution At 2.5 and 10 cm
standard solution B, which corresponds to 0,1; 0,2; 0,5; 1,0; 2,0; 5,0 and 10.0 µg/cm
of silver. To all flasks add 5 cm
of nitric acid was adjusted to the mark with water and mix. All the solutions were stored in a dark place.
2.4. Analysis
Weighed take, depending on the mass fraction of silver in the alloy. When the mass fraction of silver of at least 0.002% of the weight of the portion should be 2,0000 g. When the mass fraction of silver is equal to or more than 0,002% is 1.0000 g.
The sample of alloy is placed in a conical flask with a capacity of 250 cm, add 2 g of tartaric acid, 20 cm
of a solution of nitric acid, cover with watch glass and dissolve in low heat.
After cooling, the solution was transferred to volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.
Analyzed and standard solutions sprayed in air-acetylene flame and measure the magnitude of the absorption line of silver 328,0 nm with an atomic absorption spectrophotometer. Odnoschelevye the burner is positioned along the optical axis so that the absorption is measured over the cone of the reaction zone of the flame.
Measurement conditions selected in accordance with the applicable device. Use two ways to measure the magnitude of the absorption depending on the instrument model.
For spectrophotometers with work mode «concentration», «concentration» and get the result on the scoreboard, µg/cm, or in the mode «absorption» method «limiting solutions», or by the calibration schedule.
On the other spectrophotometers operate in the mode «absorption» recording on a recording potentiometer or by deposition on a dial or digital device.
The method of «limiting solutions» is to obtain the counts for the analyzed solution and the two standard solutions, one of which gives a higher and the other lower count compared to the count for the analyzed solution.
(Changed edition, Rev. N 2).
2.5. Processing of the results — the concentration of the element in solution, mg/cm
;
is the peak height, mm.
When measurement of the absorption line of the element by analog and digital instrument calibration curve constructed in the coordinates: — the concentration of the element in the solution, µg/cm
;
— the readings of a dial or digital device.
Mass fraction of silver () in percent is calculated by the formula
where is the concentration of silver in the sample solution, µg/cm
;
the silver concentration in the solution in the reference experiment, µ g/cm
;
the volume of the solution of the alloy, cm
;
— weight alloy, g
.
2.5.2. The discrepancy between the results of parallel measurements (the difference between the largest and smallest results of parallel measurements) and the discrepancy between the results of the analysis
(the difference between the larger and the smaller of the results of the analysis) at a confidence level
=0.95 does not exceed the allowable absolute values of the differences given in the table.
| Mass fraction of silver, % | The limit of error of the results of the analysis |
The discrepancy between the results of parallel measurements |
The discrepancy between the results of the analysis |
| From 0,0010 to 0,0020 incl. | 0,0003 |
0,0004 | 0,0004 |
| SV. 0,0020 «0,0050 « | 0,0004 |
0,0005 | 0,0005 |
| «0,0050» 0,010 « | 0,0009 |
0,0012 | 0,0012 |
| «0,010» 0,020 « | 0,002 |
0,002 | 0,002 |
| «0,020» 0,050 « | 0,003 |
0,004 | 0,004 |
| «0,050» 0,100 « | 0,005 |
0,006 | 0,006 |
The control accuracy of the analysis is carried out using standard samples or by other methods stipulated by GOST 1293.0−83.
The error analysis results (at a confidence probability =0,95) does not exceed the limit values
given in the table, under the following conditions: the discrepancy between the results of parallel measurements does not exceed the permissible, the results of accuracy control positive.
(Changed edition, Rev. N 2).
3. PHOTOMETRIC METHOD
3.1. The essence of the method
The method is based on the displacement of copper ions from its diethyldithiocarbamate complex with silver ions. The decrease in color intensity of the diethyldithiocarbamate copper proportional to the concentration of silver. The optical density of colored solutions are measured at a wavelength of 436 nm on the spectrophotometer or in a region of wavelengths 430−455 nm on a photoelectrocolorimeter.
(Changed edition, Rev. N 1).
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Acetic acid GOST 61−75 and 0.2 M solution.
Nitric acid GOST 4461−77 diluted 1:1 and 0.1 M solution.
Sodium acetate according to GOST 199−78, the solutions are 0.2 M and 500 g/DM.
Tartaric acid according to GOST 5817−77, a solution of 500 g/DM.
Ammonia water according to GOST 3760−79.
Carbon tetrachloride according to GOST 20288−74.
Sodium N, N-diethyldithiocarbamate according to GOST 8864−71, a solution of 10 g/DM.
Methyl orange, solution 10 g/DM.
Copper sulfate according to GOST 4165−78.
Silver GOST 6836−80*.
______________
* On the territory of the Russian Federation GOST 6836−2002. — Note the manufacturer’s database.
(Changed edition, Rev. N 1, 2).
3.3. Preparation for assay
3.3.1. Preparation of standard solutions of silver
Solution a: 0,1000 g of silver dissolved in 10 cmof nitric acid (1:1), evaporated to obtain a wet salts, poured 6.9 cm
of nitric acid, diluted with water, transferred to a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof the solution contains 1 mg of silver.
Solution B: 10 cmsolution A dilute 0.1 M solution of nitric acid in a volumetric flask with a capacity of 100 cm
and mixed.
1 cmof a solution contains 0.1 mg of silver.
Solution: 10 cmof a solution diluted with a 0.1 M solution of nitric acid in a volumetric flask with a capacity of 100 cm
and mixed.
1 cmof the solution contains 0.01 mg of silver.
(Changed edition, Rev. N
2).
3.3.2. Preparation of acetate buffer solution with pH 4
Mixed 800 cm0.2 M acetic acid with 200 cm
of 0.2 M solution of sodium acetate and 11.5 cm
of glacial acetic acid, diluted several times with water, add 5.44 g sodium acetate and the volume was adjusted with water to 1000 cm
.
3.3.3. Preparation of the solution of copper diethyldithiocarbamate in carbon tetrachloride
Stock solution: 40 mg of copper sulphate is dissolved in 40 cmof water, add ammonia to pH 9, flow 4.5 cm
of a solution of sodium diethyldithiocarbamate, transferred to a separatory funnel with a capacity of 150−200 cm
and extracted the copper by carbon tetrachloride in portions of 20 cm
to obtain a colorless extract. The organic extract is washed in a separating funnel twice with water, then transferred to a volumetric flask with a capacity of 500 cm
and dilute to the mark with carbon tetrachloride.
Diluted solution: 30cmbackup solution is diluted with carbon tetrachloride in a volumetric flask with a capacity of 500 cm
. The optical density of diluted solution measured against carbon tetrachloride should be 0,4−0,5
.
3.3.4. To build a calibration curve in seven of the eight glasses with a capacity of 50 cmmeasure 0,4; 0,8; 1,2; 1,6; 2,0; 2,4 and 2.8 cm
standard solution, which corresponds to 4, 8, 12, 16, 20, 24 and 28 mcg of silver. The eighth Cup, measure out 2.5 cm
of water. In all the glasses neutralize the solution at the methyl orange solution of sodium acetate and 500 g/l
to pH 4, was transferred to a separatory funnel with a capacity of 200 cm
and diluted to 100 cm
(the labels on the funnel is applied in advance) acetate buffer solution with pH 4.
Pour 20 cmof dilute solution of copper diethyldithiocarbamate, and shake the funnel with a solution of 2 min. After separation of the liquids poured a layer of carbon tetrachloride in a dry flask with a capacity of 100 cm
. After 20−30 min, measure the optical density of the solution at a wavelength of 436 nm on the spectrophotometer or in a region of wavelengths 430−455 nm on a photoelectrocolorimeter.
Solution comparison is the solution, which has not imposed a standard solution of silver.
According to the obtained values of optical density of the solutions and their corresponding silver content build the calibration graph.
All reagents required in the determination of silver, should be checked for absence of chlorine ion.
(Changed edition, Rev. N 1, 2
).
3.4. Analysis
A portion of the alloy weight 0,5000 g is placed in a conical flask with a capacity of 100 cmand dissolved by heating in a mixture of acids composed of 1 cm
of a solution of tartaric acid and 100 cm
of nitric acid (1:1). After dissolution, the sample solution is boiled to remove oxides of nitrogen.
For the mass concentration of silver in the alloy to 0.005% next, use the entire solution, the greater the mass fraction of the solution transferred to a volumetric flask with a capacity of 100 cm, is diluted to the mark with water and mix.
The entire solution or part aliquota 20 cmwhen the mass fraction of silver is 0.005 to 0.02%, or 5 cm
for the mass concentration of silver 0,02−0,1% solution neutralized with sodium acetate and 500 g/l
methyl orange according to pH 4, was transferred to a separatory funnel with a capacity of 200 cm
and then do as stated in claim
As a solution comparison using the solution in the reference experiment.
Weight of silver found by the calibration schedule.
(Changed edition, Rev. N 2).
3.5. Processing of the results
3.5.1. Mass fraction of silver () in percent is calculated by the formula
where is the mass of silver in the sample solution, found by calibration schedule, mcg;
— volume of initial solution alloy, cm
;
— weight alloy, g;
— volume aliquote part of the solution, cm
.
3.5.2. The discrepancy between the results of parallel measurements (the difference between the largest and smallest results of parallel measurements) and the discrepancy between the results of the analysis
(the difference between the larger and the smaller of the results of the analysis) at a confidence level
=0.95 does not exceed the allowable absolute values of the differences given in the table.
The control accuracy of the analysis is carried out using standard samples or by other methods stipulated by GOST 1293.0−83.
The error analysis results (at a confidence probability =0,95) does not exceed the limit values
given in the table, under the following conditions: the discrepancy between the results of parallel measurements does not exceed the permissible, the results of accuracy control positive.
(Changed edition, Rev. N 2).
