GOST 20580.4-80
GOST 20580.4−80 (ST SEV 909−78) Lead. Methods for determination of bismuth (with Amendments No. 1, 2)
GOST 20580.4−80*
(ST CMEA 909−78)
Group B59
STATE STANDARD OF THE USSR
LEAD
Methods for determination of bismuth
Lead. Methods for the determination of bismuth
AXTU 1709***
________________
*** Revised edition, Edit. N 2.
Date of introduction 1980−12−01
Resolution of the USSR State Committee for standards, dated April 29, 1980, N 1976 the period of validity set with 01.12.80
Proven in 1983 by the Decree of Gosstandart from
________________
** Expiration removed by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (I & C N 11, 1995). — Note the manufacturer’s database.
REPLACE GOST 20580.4−75
* REPRINT December 1984, Change No. 1, approved in December 1983 (ICS 4−84)
The Change N 2, approved and put in force by the Decision of Gosstandart of the USSR from
Change No. 2 made by the manufacturer of the database in the text IUS N 11, 1990
This standard establishes photometric methods for determination of bismuth from 0.001 to 0.2% in lead (99,992−99,5%).
The standard fully complies ST SEV 909−78.
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis and security requirements — according to GOST 20580.0−80.
(Changed edition, Rev. N 2).
1.2. (Deleted, Rev. N 2).
2. PHOTOMETRIC METHOD WITH THE SEPARATION OF BISMUTH EXTRACTION IN THE FORM OF CARBAMYLATE WITH THE USE OF CYANIDE
The method is based on extraction of bismuth in the form of carbamylate carbon tetrachloride from the ammonia solution in the presence of EDTA and potassium cyanide. The organic extract is evaporated to dryness in the presence of nitric acid. Further, in a nitrate environment, bismuth, interacting with thiourea forms a yellow complex, which photometrical at a wavelength of 470 nm.
2.1. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter of any kind for measurements in the visible region of the spectrum.
Nitric acid GOST 4461−77 and diluted 1:1 and 2:5.
Tartaric acid according to GOST 5817−77.
Citric acid according to GOST 3652−69.
Mix to dissolve and 200 g of tartaric acid and 200 g of citric acid dissolved in water and diluted to 1000 cm.
Ammonia water according to GOST 3760−79 and diluted 2:1.
Potassium cyanide, solution with a mass concentration of 100 g/DM.
Thiourea according to GOST 6344−73, a solution with a mass concentration of 100 g/DM, freshly prepared.
Diethyldithiocarbamate sodium GOST 8864−71, a solution with a mass concentration of 10 g/DM. The solution should be freshly prepared and filtered.
Carbon tetrachloride according to GOST 20288−74.
Ethylenediamine-N, N, N', N'-tetraoxane acid disodium salt, 2-water (EDTA) according to GOST 10652−73, a solution with a mass concentration of 400 g/DM. 40 g of EDTA was dissolved with heating in a weak solution of ammonia (2:1), bring the same solution to a volume of 100 cm
.
Phenolphthalein on the other 6−09−5360−87, a solution with a mass concentration of 10 g/lin ethanol.
Ethyl alcohol GOST 18300−87.
Bismuth GOST 10928−75*.
_______________
* Valid GOST 10928−90, here and hereafter. — Note the manufacturer’s database.
A standard solution of bismuth.
0,100 g of bismuth was dissolved with heating in 50 cmof nitric acid (1:1), cooled, 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 0.1 mg of bismuth.
(Changed edition, Rev. N 2).
2.2. Analysis
2.2.1. Depending on the expected mass fraction of bismuth take a sample of lead whose mass is listed in table.1.
Table 1
| Mass fraction of bi, % |
The weight of the portion of the lead, g |
| From 0.001 to 0.005 |
5,000 |
| SV. 0,005 «0,01 |
2,000 |
| «Is 0.01» to 0.03 |
1,000 |
| «To 0.03» to 0.05 |
0,500 |
| «0,05» 0,2 |
0,250 |
A portion of the lead is placed in a conical flask with a capacity of 250 cm, and dissolved in 10 cm
of the mixture for dissolution, and 10 cm
of nitric acid (1:1). By dissolving 5 g of the sample using 30 cm
of the mixture for dissolution and 20 cm
of nitric acid (1:1).
After dissolution, the solution was cooled, add 5 drops of solution of phenolphthalein and neutralized with ammonia until the appearance of pink color. The solution was cooled, transferred to a separatory funnel with a capacity of 250 cm, the volume was adjusted to 50 cm
. Add 50 cm
of EDTA solution, 2 cm
of a solution of sodium diethyldithiocarbamate, 10−20 cm
of a solution of potassium cyanide (in accordance with a mass fraction of copper, zinc, silver) and extracted with 20 cm
of carbon tetrachloride for 2 minutes Drained the organic layer into a glass with a capacity of 100 cm
and extraction with 2 cm
of sodium diethyldithiocarbamate and 20 cm
of carbon tetrachloride repeat. The combined extracts was evaporated to dryness. To the dry residue add 10 cm
of nitric acid and again evaporated to dryness. Add 10 cm
of nitric acid (2:5) and boil for 1−2 min. After cooling, add 10 cm
of a solution of thiourea, the solution was transferred to a volumetric flask with a capacity of 50 cm
, is diluted to the mark with water and mix. If necessary, the solution is filtered through a dense filter.
The optical density of solutions measured at a wavelength of 470 nm.
Solution comparison is water.
At the same time carried out control experiments under the same conditions with all used during the analysis, reagents.
The amount of bismuth in kalorimetricheskim volume set calibration schedule.
(Changed edition, Rev. N 2).
2.2.2. To build a calibration curve in seven of the eight volumetric flasks with a capacity of 50 cmmake 0,5; 1,0; 1,5; 2,0; 2,5; 3,0 and 5.0 cm
standard solution of bismuth. Eighth a volumetric flask is used for the reference experiment. To all flasks add 10 cm
of nitric acid (2:5), 10 cm
solution of thiourea, diluted to the mark with water, mix and photometric as specified in claim
According to the obtained values of optical densities and their corresponding grades of bismuth build the calibration graph.
3. PHOTOMETRIC METHOD WITH THE SEPARATION OF LEAD AS SULPHATE
The method is based on the formation tiomochevina complex of bismuth and its fotomaterialy in the region of wavelengths 390−413 nm after separation of lead as sulphate.
3.1. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter of any kind for measurements in the visible region of the spectrum.
Nitric acid GOST 4461−77 diluted 1:1 and the solution (HNO
)=1 mol/DM
.
Sulfuric acid GOST 4204−77, diluted 1:1.
Thiourea according to GOST 6344−73, a solution with a mass concentration of 100 g/DM, freshly prepared.
Bismuth metal according to GOST 10928−75.
A standard solution of bismuth.
Solution a: 0,100 g of bismuth dissolved in 20 cmof nitric acid (1:1). Boil to remove oxides of nitrogen. Pour 20 cm
of water and transfer the solution into a measuring flask with volume capacity of 1000 cm
. Topped up to the mark solution of nitric acid of concentration 1 mol/l
and stirred.
1 cmof solution A contains 0.1 mg of bismuth.
(Changed edition, Rev. N 1, 2).
3.2. Analysis
3.2.1. Depending on the expected mass fraction of bismuth take a sample of lead whose mass is listed in table.2.
Table 2
| Mass fraction of bi, % |
The mass of charge, g |
The volume of the volumetric flask for dilution, see |
The volume aliquote part of the solution, cm |
| From 0,001 to 0,006 |
5,000 |
50 |
25 |
| SV. 0,006 «0,03 |
2,000 |
100 |
25 |
| «0,03» 0,08 |
1,000 |
100 |
20 |
| «Of 0.08» to 0.2 |
1,000 |
100 |
5 |
The sample is placed in a conical flask with a capacity of 100 cm, is dissolved in 30 cm
of nitric acid (1:1), poured 10−20 cm
of water and boil to remove oxides of nitrogen. Cool, transferred to volumetric flasks with a capacity of 50 or 100 cm
(table.2), poured 3 cm
of sulphuric acid (1:1), made up to the mark with water and mix. After 2 h the filtered solution in a clean, dry flask through the dense filter and aliquot a portion of the filtrate (table.2), placed in a volumetric flask with a capacity of 50 cm
. Add 10 cm
of a solution of thiourea, adjusted to the mark with water and mix.
After 10−15 minutes, measure the optical density of the solutions in the region of wavelengths 390−413 nm.
Solution comparison is water.
At the same time carried out control experiments for inclusion in the result of the relevant amendment.
The amount of bismuth in kalorimetricheskim volume set calibration schedule.
(Changed edition, Rev. N 2)
.
3.2.2. To build a calibration curve in six of the seven volumetric flasks with a capacity of 50 cmis placed 0,25; 0,5; 1,0; 1,5; 2,0 and 2,5 cm
standard solution of bismuth, which corresponds to 25; 50; 100; 150; 200 and 250 µg of bismuth (seventh is used for the reference experiment). The solution was diluted to 10 cm
of water, poured 20 cm
of nitric acid (1:1), 3 cm
of sulphuric acid (1:1) 10 cm
solution of thiourea. Bring to mark with water and then do as described in claim
On the found values of optical densities and their corresponding mass fractions of bismuth build the calibration graph.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of bismuth in percent is calculated by the formula
where — weight of bismuth, was found in the calibration schedule g;
— volume of initial solution, cm
;
— volume aliquote part of the solution, cm
;
— its weight of lead,
(Changed edition, Rev. N 1).
4.2. Allowable absolute discrepancies in the results of parallel measurements and the results of the analysis shall not exceed the values given in table.3.
Table 3
| Mass fraction of bi, % |
The allowable divergence of the parallel definitions % |
Permissible discrepancies in the results of the analysis % |
| From to 0,0010 0,0030 incl. |
0,0003 |
0,0004 |
| SV. 0,0030 «0,0050 « |
0,0005 |
About 0.0006 |
| «0,0050» 0,0100 « |
0,0010 |
0,0013 |
| «0,010» 0,020 « |
0,002 |
0,003 |
| «0,020» 0,040 « |
0,004 |
0,005 |
| «0,040» 0,070 « |
0,006 |
0,007 |
| «0,070» 0,100 « |
0,008 |
0,010 |
| «To 0.10» to 0.20 « |
0,01 |
0,02 |
(Changed edition, Rev. N 2).
