GOST 1652.12-77
GOST 1652.12−77 Alloys copper-zinc. Methods for determination of silicon (with Amendments No. 1, 2, 3)
GOST 1652.12−77
Group B59
STATE STANDARD OF THE USSR
ALLOYS COPPER-ZINC
Methods for determination of silicon
Copper-zinc alloys.
Methods for the determination of silicon
AXTU 1709
Date of introduction 1978−07−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
Y. F. Chuvakin, M. B. Taubkin, A. A. Nemodruk, N. In. Egiazarov (supervisor), I. A. Vorobyev
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 1652.12−71
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
The number of the paragraph, subparagraph |
| GOST 8.315−91 |
2.4.4, 3.4.4 |
| GOST 83−79 |
2.2 |
| GOST 859−78 |
3.2 |
| GOST 1020−77 |
Chapeau |
| GOST 1652.1−77 |
1.1 |
| GOST 3118−77 |
2.2 |
| GOST 3652−69 |
3.2 |
| GOST 3760−79 |
3.2 |
| GOST 3765−78 |
3.2 |
| GOST 4204−77 |
2.2, 3.2 |
| GOST 4207−75 | 2.2 |
| GOST 4461−77 |
2.2, 3.2 |
| GOST 6552−80 |
3.2 |
| GOST 6691−77 |
3.2 |
| GOST 9428−73 |
3.2 |
| GOST 10484−78 |
2.2, 3.2 |
| GOST 11293−89 |
2.2 |
| GOST 15527−70 |
Chapeau |
| GOST 17711−93 |
Chapeau |
| GOST 18300−87 |
3.2 |
| GOST 25086−87 |
1.1, 2.4.4, 3.4.4 |
5. Resolution of the state standard from
6. REPRINT (July 1997) with Amendments No. 1, 2, 3, approved in October 1981, November 1987-December 1992 (IUS 12−81, 2−88, 3−93)
This standard specifies the gravimetric method for determination of silicon (with a mass fraction of silicon of from 1% to 5%) and photometric method for determination of silicon (with a mass fraction of silicon from 0.05 to 1%) in copper-zinc alloys according to GOST 15527, GOST and GOST 17711 1020.
(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 1652.1.
(Changed edition, Rev. N 2).
2. GRAVIMETRIC METHOD FOR DETERMINATION OF SILICON
2.1. The essence of the method
The method is based on the allocation of silicic acid by precipitation of its hydrochloric acid from gelatin solution of.
2.2. Reagents and solutions
Nitric acid according to GOST 4461.
Sulfuric acid according to GOST 4204, and diluted 1:4.
Hydrochloric acid according to GOST 3118 and diluted 5:95.
Hydrofluoric acid according to GOST 10484.
Acids mixture to dissolve; preparing a mixture of one part nitric acid and two parts of hydrochloric acid.
Gelatin food according to GOST 11293, a solution of 10 g/DM.
Potassium ferrocyanide according to GOST 4207, a solution of 30 g/DM.
Sodium carbonate according to GOST 83.
2.3. Analysis
A sample of alloy weighing 1 g is placed in a beaker with a capacity of 250 cm, and dissolved in 20 cm
of a mixture of acids. Strengthening with the help of a tripod over the glass a funnel (to avoid dust), the solution was evaporated to dryness. Moisten the residue in 10 cm
of concentrated hydrochloric acid and evaporated to dryness two more times, each time adding 10 cm
of hydrochloric acid and 3−5 min pour 70−80 cm
of hot water, 5 cm
of a solution of gelatin and heated until complete dissolution of salts. Filtered the precipitated precipitate a solid filter containing a small amount filtrowanie mass, and washed 5−8 times with hot hydrochloric acid, diluted 5:95, to a negative reaction of wash water on copper (sample with solution of ferrocyanide of potassium). After this precipitate was washed 3−4 times with hot water. The filtrate is subjected to twice the evaporation with hydrochloric acid. Additional precipitate of silicon dioxide is filtered off and washed with hot water. Both sludge along with the filter placed in a platinum crucible, dried, incinerated, add 0.5 cm
of concentrated nitric acid, dried and calcined at 1000−1050 °C for 30 min, and then the crucible is cooled in the desiccator and weighed. To the residue in a platinum crucible add 1−2 drops of water, 1 cm
hydrofluoric acid, 2−3 drops of sulphuric acid, carefully evaporated to dryness and the residue calcined at 1000−1050 °C for 25 min. After cooling in the desiccator the crucible is weighed again.
If after the removal of silicic acid in the crucible remains a black precipitate of elemental silicon, it is fused with anhydrous sodium carbonate. The crucible is placed in a beaker and the melt is treated with sulfuric acid, diluted 1:4. The crucible is removed, washed with water and the solution was evaporated until a white smoke. After cooling, add 80 cmwater, 5 cm
of hydrochloric acid and heat nearly to boiling. Allocated an additional precipitate of silicic acid is filtered off, washed, burned, and further analysis are as described above.
2.4. Processing of the results
2.4.1. Mass fraction of silicon in percent is calculated by the formula
where is the mass of the crucible with the precipitate of silicon dioxide prior to processing hydrofluoric acid, g;
— weight of crucible with residue after treatment with hydrofluoric acid, g;
— weight alloy, g;
0,4672 — the ratio of silicon dioxide to silicon.
2.4.2. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed the permissible values specified in the table.
| Mass fraction of silicon |
|
|
| From 0.05 to 0.10 incl. |
0,1* |
0,014 |
| SV. Of 0.10 «to 0.25 « |
0,015 |
0,02 |
| «0,25» 0,50 « |
0,03 |
0,04 |
| «To 0.50» and 1.0 « |
0,05 |
0,07 |
| «To 1.0» and 5.0 « |
0,08 |
0,1 |
________________
* The text of the document matches the original. — Note the manufacturer’s database.
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 (the reproducibility) shall not exceed the values given in the table.
(Changed edition, Rev. N 2, 3).
2.4.4. The control accuracy of the analysis is conducted under the State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) copper-zinc alloys, approved under GOST 8.315, or by a method of additives in accordance with GOST 25086.
2.4.4.1,
3. PHOTOMETRIC METHOD FOR DETERMINATION OF SILICON
3.1. The essence of the method
The method is based on the formation of the silicon molybdenum yellow flint-molybdenum acid and measuring the optical density of colored solution.
3.2. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter.
Nitric acid according to GOST 4461, diluted 1:2.
Sulfuric acid according to GOST 4204, diluted 1:1.
Hydrofluoric acid according to GOST 10484.
Citric acid according to GOST 3652, a solution of 100 g/DM.
Orthophosphoric acid according to GOST 6552, diluted 1:9.
Boric acid, saturated solution. About 60 g of boric acid are dissolved in 1000 cmof hot water. Before administration, the solution is cooled to a temperature of about 20 °C.
Ammonia water according to GOST 3760, diluted 1:1.
Copper of mark M0 GOST 859.
Urea according to GOST 6691, a solution of 100 g/DM.
Crystal violet, an aqueous solution of 1 g/DM.
Ammonium molybdate according to GOST 3765, recrystallized freshly prepared solution of 150 g/DM.
For recrystallization 70 g of ammonium molybdate was dissolved in 400 cmof water at low heat (70−80 °C). The solution was filtered 2 times through a dense filter. Then transfer the solution into a large beaker, cooled and added to 250 cm
of ethyl alcohol. After standing for 1 h the separated crystals are aspirated. Received ammonium molybdate is dissolved in water and repeat the recrystallization.
After the second suction, the crystals washed several times with mixture of alcohol and water (5:8) and dried in air.
The technical rectified ethyl alcohol according to GOST 18300 and diluted 5:8.
Sodium-potassium carbonate.
Silicon dioxide according to GOST 9428.
Standard solutions of silicon.
Solution A, prepared as follows: 0,2143 g of calcined silicon dioxide is fused in a platinum crucible with 2 g of sodium-potassium carbonate. The alloy is leached with water and transferred to a volumetric flask with a capacity of 500 cm, label to top up with water and quickly transferred to a plastic vessel.
1 cmof the solution contains 0.0002 g of silicon.
Solution B is prepared as follows: 10 cmof the solution And transferred to a volumetric flask with a capacity of 100 cm
, is diluted to the mark with water and quickly transferred to a plastic vessel.
1 cmof the solution contains 0,00002 g of silicon.
The copper solution to prepare the solution of the comparison; prepared as follows: 1 g of copper is placed in a platinum Cup, add 1 cmhydrofluoric acid, 10 cm
of nitric acid, diluted 1:2. The dissolution is carried out under heating. Then add 2.5 cm
of sulphuric acid diluted 1:1, and the solution is heated to release sulfur trioxide, and then to remove free sulfuric acid. After cooling the salt is dissolved, adding a small amount of water, 10 cm
of nitric acid, diluted 1:2, 1 cm
hydrofluoric acid. Then add 30 cm
of boric acid, the solution transferred to a volumetric flask with a capacity of 100 cm
, top up to the mark with water and mix.
3.3. Analysis
3.3.1. A sample weighing 0.5 g was placed in Teflon or platinum crucible, add 1 cmhydrofluoric acid, 10 cm
of nitric acid, diluted 1:2, and is available in platinum or Teflon cover. The dissolution is carried out by heating in a water bath to 60 °C. After dissolution in a crucible add 10 cm
of boric acid solution and transfer the solution through a polyethylene funnel into a measuring flask with a capacity of 100 cm
with 20 cm
solution of boric acid, made up to the mark with water and mix.
Aliquot part of the solution was 10 cm(with a mass fraction of silicon from 0.05 to 0.25%), 5 cm
(with a mass fraction of silicon from 0.25 to 0.5%) or 2,5 cm
(with a mass fraction of silicon of from 0.5 to 1%) were placed in a glass with a capacity of 50 cm
, top up with water to 20 cm
and neutralized with ammonia under constant stirring to a pH of 1.5. Set the pH drip test with a solution of crystal violet on a white plate. When the pH value is less than 1.5 a drop of test solution, mixed with a drop of the indicator solution, is colored in green; at pH equal to 1.5, drop color becomes pure blue. If ammonia is introduced in excess, the drop has a purple color. In such cases, add nitric acid diluted 1:2, to obtain a coloring drop of green and then carefully repeat the neutralization with ammonia. In a solution of pH 1.5 is added 5 cm
of a solution of urea, 5 cm
of molybdenic acid ammonium solution and leave for 10 mins then insert 5 cm
of a solution of citric acid, 3 cm
of a solution of phosphoric acid, the mixture is transferred into a measuring flask with a capacity of 50 cm
, top up to the mark with water and mix. After 15 min measure the optical density of the solution on the spectrophotometer or photoelectrocolorimeter at a wavelength of 400 nm in a cuvette with a layer thickness of 5 cm relative to the comparison solution. Reference solution prepared simultaneously with the sample, taking the copper solution (see p.3.2) in the same amount as the analyzed solution.
The silicon content found by the calibration schedule.
(Changed edition, Rev. N 2).
3.3.2. Construction of calibration curve
To build a calibration curve of six tumblers with a capacity of 50 cm andadd 10 cm
of copper solution, containing silicon (reference solution), and then type 0; 1,0; 2,0; 4,0; 6,0 and 8,0 cm
standard solution B.
The solutions were diluted with water to 20 cmand further analysis are as indicated in claim
3.4. Processing of the results
3.4.1. Mass fraction of silicon in percent is calculated by the formula
where is the mass of silicon was found in the calibration schedule g;
— the weight of the portion corresponding to aliquote part of the solution,
3.4.2. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed the permissible values specified in the table.
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 (the reproducibility) shall not exceed the values given in the table.
3.4.2,
3.4.4. The control accuracy of the analysis is conducted under the State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) copper-zinc alloys, approved under GOST 8.315, or by a method of additives in accordance with GOST 25086.
3.4.4.1,
