GOST 1953.15-79
GOST 1953.15−79 Bronze tin. Methods for determination of arsenic (with Amendments No. 1, 2)
GOST 1953.15−79
Group B59
INTERSTATE STANDARD
BRONZE TIN
Methods for determination of arsenic
Tin bronze.
Methods for the determination of arsenic
AXTU 1709
Date of introduction 1981−01−01
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. REPLACE GOST 1953.15−76
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph, sub-paragraph |
| GOST 8.315−97 |
3.4.4 |
| GOST 613−79 |
Chapeau |
| GOST 614−97 |
Chapeau |
| GOST 1953.1−79 |
1.1 |
| GOST 1953.4−79 |
2.2, 3.2 |
| GOST 3118−77 |
2.2, 3.2 |
| GOST 3760−79 |
3.2 |
| GOST 3765−78 |
2.2, 3.2 |
| GOST 4160−74 |
2.2 |
| GOST 4204−77 |
2.2, 3.2 |
| GOST 4205−77 |
3.2 |
| GOST 4232−74 |
3.2 |
| GOST 4328−77 |
2.2 |
| GOST 4461−77 |
2.2, 3.2 |
| GOST 5841−74 |
2.2, 3.2 |
| GOST 6552−80 |
2.2, 3.2 |
| GOST 10929−76 |
2.2, 3.2 |
| GOST 14204−69 |
2.2 |
| GOST 18300−87 |
2.2 |
| GOST 20288−74 |
3.2 |
| GOST 20490−75 |
2.2, 3.2 |
| GOST 25086−87 |
1.1, 2.4.4, 3.4.4 |
5. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)
6. EDITION with Amendments No. 1, 2 approved in February 1983, August 1990 (IUS 6−83,11−90)
This standard specifies the photometric and extraction-photometric methods for determination of arsenic (from 0.01% to 0.15%) in tin bronze according to GOST GOST 613 and 614.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 with the Supplement according to claim 1.1 GOST 1953.1.
(Changed edition, Rev. N 1, 2).
2. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF ARSENIC
2.1 the essence of the method
The method involves a preliminary separation of arsenic transport in the form of trichloride of arsenic from hydrochloric acid solution in the presence of phosphoric acid, followed by formation of yellow molybdenumsteel acid by reduction of its sulfate with hydrazine in acidic solution to arsenic-molybdenum blue and the measurement of the optical density of colored solution.
2.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Device for the determination of arsenic in steel and cast iron according to GOST 14204.
Nitric acid according to GOST 4461.
Hydrochloric acid according to GOST 3118 and diluted 1:3.
Sulfuric acid according to GOST 4204, diluted 1:1 and 3 mol/DMsolution.
Orthophosphoric acid according to GOST 6552.
A mixture of acids, is prepared as follows: one volume of nitric acid mixed with three volumes of hydrochloric acid.
Hydrogen peroxide (perhydrol) according to GOST 10929.
Hydrazine sulfate according to GOST 5841 and a solution of 1.5 g/DM.
Potassium bromide crystal according to GOST 4160.
Mixture of hydrazine sulphate and bromide of potassium are prepared as follows: 1 part of hydrazine sulfate are mixed with 1 part of bromide of potassium.
Ammonium molybdate according to GOST 3765, recrystallized from alcoholic solution (recrystallization of ammonium molybdate according to GOST 1953.4), a solution of 10 g/DM3 mol/DM
solution of sulphuric acid.
Potassium permanganate according to GOST 20490, a solution of 1 g/DM.
Hydrazine-molybdate solution; prepared as follows: to 50 cmof a solution of ammonium molybdate add 5 cm
of a solution of hydrazine sulphate and dilute with water to 100 cm
. Use freshly prepared solution.
Rectified ethyl alcohol according to GOST 18300.
Sodium hydroxide according to GOST 4328, solution 100 g/DM.
Phenolphthalein, solution at 10 g/lin ethanol.
Arsenious anhydride.
Standard solutions of arsenic. Solution A, prepared as follows: 0,1320 g of arsenious anhydride is dissolved by heating in 10 cmof sodium hydroxide solution, the solution transferred to a volumetric flask with a capacity of 500 cm
, neutralized with hydrochloric acid, diluted 1:3, phenolphthalein, made up to the mark with water and mix.
1 cmof the solution contains 0.0002 g of arsenic.
Solution B is prepared as follows: 25 cmsolution And placed in a volumetric flask with a capacity of 500 cm
, made up to the mark with water and mix.
1 cmof solution B contains 0,00001
g of arsenic.
2.3. Analysis
2.3.1. A portion of the alloy (see table.1) is placed in a beaker with a capacity of 250 cm, add 20 cm
of a mixture of acid, cover with watch glass and dissolved under heating. After dissolution, the watch glass and walls of glass should be rinsed with a small amount of water to the cooled solution add 10 cm
sulphuric acid diluted 1:1, and is evaporated until a white smoke of sulfuric acid. The residue is cooled, gently dissolve it in 20−25 cm
of water and transfer the solution into the flask of the apparatus for distillation of arsenic. Then add 1 g of a mixture of hydrazine sulfate with potassium bromide and close the flask with a stopper with the refrigerator.
Table 1
| Mass fraction of arsenic, % |
The weight of the portion of the alloy, g |
| From 0.01 to 0.05 |
0,5 |
| SV. 0,05 «0,1 |
0,25 |
| «0,1» 0,15 |
0,1 |
The glass, which produced a dissolution residue rinse 10 cmof concentrated hydrochloric acid and transfer it through the funnel into the flask of the apparatus for distillation of arsenic. In a flask, add 50 cm
of concentrated hydrochloric acid and 5 cm
of phosphoric acid, a few glass beads and distilled arsenic trichloride in the form of arsenic. The Stripping is continued until the reduction of the initial volume of the solution
.
The distillate collected in the flask-receiver with a capacity of 250 cm, containing 25−30 cm
of water and avoid possible volatilization of arsenic in a flask-trap with 10−15 cm
of water. To both flasks add 1−2 drops of hydrogen peroxide solution.
At the end of the distillation the distillate and the liquid from the flask-trap combined, add 10 cmof concentrated nitric acid and evaporate the solution to dryness. A glass of dry residue is transferred to a drying Cabinet and leave for 1 h at 120−130 °C. the Dry residue moistened with 1−2 drops of sodium hydroxide solution, add 30 cm
of water and boil for 3−5 min. After cooling, the solution is neutralized with sulfuric acid, diluted 1:5, on indicator paper «Congo» and beyond that in the excess add 3−5 drops of acid.
The solution was transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water, not containing reducing materials, and mix. The water should be pre-tested for reducing substances by the addition dropwise of a solution of potassium permanganate until slightly pink color.
Aliquot part of the solution (10 cm) placed in a volumetric flask with a capacity of 50 cm
, up to 4 cm
of hydrazine molibdate solution, add water to 35−40 cm
and placed in a boiling water bath. After 10−15 min the solution was cooled, made up to the mark with water, mix and measure optical density on a photoelectrocolorimeter with a red light filter in the cell with thickness of the absorbing layer 5 cm or on the spectrophotometer at 840 nm in a cuvette with a thickness of absorbing layer 1 cm as a solution of comparison, using the solution kontrolnog
on experience.
2.3.2. Construction of calibration curve
In glasses with a capacity of 100 cmplaced 0; 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 and 6.0 cm
of standard arsenic solution, add 10 cm
of concentrated nitric acid, cautiously evaporate the solution to dryness. A glass of dry residue is transferred to a drying Cabinet and then received, as indicated in claim
2.4. Processing of the results
2.4.1. Mass fraction of arsenic () in percent is calculated by the formula
where the quantity of arsenic was found in the calibration schedule g;
— weight of alloy, suitable aliquote part,
2.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.1A.
Table 1A
| Mass fraction of arsenic, % |
|
|
| From 0.01 to 0.02 incl. |
0,004 |
0,006 |
| SV. 0,02 «0,05 « |
0,007 |
0,01 |
| «To 0.05» to 0.15 « |
0,01 |
0,01 |
(Changed edition, Rev. N 2).
2.4.3. 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.1A.
2.4.4. Control the accuracy of the results of the analysis carried out by the State samples of tin bronzes, re-approved by GOST 8.315, or by a method of additives in accordance with GOST 25086.
2.4.5. The photometric method is used in case of disagreement in assessing the quality of tin bronzes.
2.4.3−2.4.5. (Added, Rev. N 2).
3. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF ARSENIC
3.1. The essence of the method
The method is based on formation of yellow arsenic-molybdenum complex followed by reduction of its sulfate with hydrazine in acidic solution to arsenic-molybdenum blue and the measurement of the optical density of colored solution after prior separation of the arsenic.
Arsenic is pre-separated by its coprecipitation with ferric hydroxide and subsequent extraction in the form of iodide of arsenic with carbon tetrachloride and reextraction with water.
3.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Nitric acid according to GOST 4461.
Hydrochloric acid according to GOST 3118 and diluted 1:3.
Orthophosphoric acid according to GOST 6552.
Sulfuric acid according to GOST 4204, diluted 1:4 and 3 mol/DMsolution.
A mixture of acids, is prepared as follows: one volume of concentrated nitric acid mixed with three parts of concentrated hydrochloric acid.
Sodium hydroxide according to GOST 4328, solution 100 g/DM.
Ammonia water according to GOST 3760 and diluted 1:50.
Ammonium molybdate according to GOST 3765, recrystallized from alcoholic solution (recrystallization of ammonium molybdate according to GOST 1953.4); a solution of 10 g/lin sulfuric acid 3 mol/DM
.
Hydrazine sulfate according to GOST 5841 and a solution of 1.5 g/DM.
Potassium iodide according to GOST 4232; 0.12 mole/DMsolution in concentrated hydrochloric acid; prepared as follows: 10 g of potassium iodide dissolved in 600 cm
of concentrated hydrochloric acid. The solution is prepared the day of application.
Alum salesonline by ND, a solution of 10 g/DMis prepared as follows: 10 g of alum was dissolved with heating in 70 cm
water and 5 cm
of concentrated nitric acid; the solution was filtered and diluted with water to 100 cm
.
Potassium permanganate according to GOST 20490, a solution of 1 g/DM.
Hydrogen peroxide (perhydrol) according to GOST 10929.
Hydrazine-molybdate solution; prepared as follows: to 50 cmof a solution of ammonium molybdate add 5 cm
of a solution of hydrazine sulphate and dilute with water to 100 cm
, using freshly prepared solution.
Wash solution is prepared as follows: three parts of a solution of potassium iodide is mixed with one part water.
The technical rectified ethyl alcohol according to GOST 18300.
Phenolphthalein, solution at 10 g/lin ethanol.
Carbon tetrachloride according to GOST 20288.
Arsenious anhydride.
Standard solutions of arsenic. Solution A, prepared as follows: 0,1320 g of arsenious anhydride is dissolved by heating in 10 cmof sodium hydroxide solution, transfer the solution into a volumetric flask with a capacity of 500 cm
, neutralized to phenolphthalein with hydrochloric acid diluted 1:3, made up to the mark with water and mix.
1 cmof the solution contains 0.0002 g of arsenic.
Solution B is prepared as follows: 25 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof solution B contains 0,
00005 g of arsenic.
3.3. Analysis
3.3.1. A portion of the alloy (see table.2) is placed in a beaker with a capacity of 300 cm, add 20 cm
of a mixture of acid, cover with watch glass and dissolved under heating. The solution was cooled, diluted with water to 120−150 cm
, add 1 cm
of solution gentoomaniac alum and ammonia to complete the transition of copper in a soluble ammonia complex. Solution and the precipitate was aged at 60 °C for coagulation of the precipitate hydroxides of iron, tin, and arsenic.
Table 2
| Mass fraction of arsenic, % |
The weight of the portion of the alloy, g |
| From 0.01 to 0.05 |
0,5 |
| SV. 0,05 «0,1 |
0,25 |
| «0,1» 0,15 |
0,1 |
The precipitate was filtered off on a medium density filter, a glass filter and the precipitate was washed 6−8 times with hot ammonia solution, diluted 1:50, dissolve the precipitate on the filter with 25 cmhot sulphuric acid, diluted 1:4, collecting the solution in a glass, which made the deposition. Filter 5−7 times washed with hot water and the solution is evaporated until a white smoke of sulfuric acid. After cooling, rinse the walls of the glass with water and evaporated again until a white smoke of sulfuric acid.
In a glass add 0.2−0.3 g of hydrazine sulfate and heated for 5−10 min.
The residue is dissolved in 35−40 cmof water, add 5 cm
of phosphoric acid and the solution transferred to a volumetric flask with a capacity of 50 cm
, is diluted to the mark with water and mix.
Aliquot part of the solution (10 cm) was placed in a separating funnel with a capacity of 250 cm
, add 60 cm
of a solution of potassium iodide, 30 cm
of carbon tetrachloride and extracted arsenic for 2 min. the Organic layer drained into another separatory funnel with a capacity of 100−150 cm
, and in the first add 15 cm
of carbon tetrachloride and repeat the extraction again. The combined extracts are washed for 20 with 20 cm
wash solution is drained and the organic layer to a third separating funnel with a capacity of 100−150 cm
. Then pour the organic layer 15 cm
of water and extragere arsenic for 2 min. the Organic layer is poured into the fourth separating funnel with a capacity of 100−150 cm
and repeat the Stripping under the same conditions. Water layers merge into a measuring flask with a capacity of 50 cm
, is added dropwise a solution of potassium permanganate until a stable pink colour, which is then to destroy, adding dropwise a solution of hydrazine sulfate. To the resulting solution was added to 4 cm
of hydrazine molybdates of the solution and the flask with the solution was placed in a boiling water bath. After 10−15 min the solution was cooled, made up to the mark with water, mix and measure optical density of solution on a photoelectrocolorimeter with a red light filter in the cell with thickness of the absorbing layer 5 cm or on the spectrophotometer at 840 nm in a cuvette with a thickness of absorbing layer 1 cm relative to the control solution
wow experience.
3.3.2. Construction of calibration curve
In glasses with a capacity of 250 cmis placed 0; 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 and 6.0 cm
to the standard solution of arsenic, is added to 20 cm
of a mixture of acids, the solution was diluted to 150 cm
of water, add 1 cm
of solution gentoomaniac alum and then received, as indicated in paragraph
3.4. Processing of the results
3.4.1. Mass fraction of arsenic () in percent is calculated by the formula
where the quantity of arsenic was found in the calibration schedule g;
— weight of alloy, suitable aliquote part of the solution,
3.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for
3) specified in table.1A.
(Changed edition, Rev. N 2).
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.1A.
3.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or by a method of additives in accordance with GOST 25086.
3.4.3,
