GOST 1762.1-71
GOST 1762.1−71 Silumin ingots. Methods for determination of silicon (with Amendments No. 1, 2)
GOST 1762.1−71
Group B59
STATE STANDARD OF THE USSR
SILUMIN IN PIGS
Methods for determination of silicon
Aluminium-silicon alloy ingots.
Methods for determination of silicon
AXTU 1709
Valid from 01.01.73
to 01.07.95*
_______________________________
* Expiration removed
Protocol N 4−93 inter-state Council
for standardization, Metrology and certification.
(IUS N 4, 1994). — Note the CODE.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
THE DEVELOPERS OF THE STANDARD
A. A. Kostyukov, G. A. Romanov, N. M. Gertseva, A. P. Nechitailov, V. A. Lavrov
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. The frequency of inspection — 5 years
4. REPLACE GOST 1762−51 (in terms of sec. II)
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | Item number | |
| GOST 83−79 | Sec. 2, 5 | |
| GOST 1762.0−71 | 1.1 | |
| GOST 3118−77 | Sec. 2, 5 | |
| GOST 3765−78 | Sec. 5 | |
| GOST 4109−79 | Sec. 2 | |
| GOST 4199−76 | Sec. 2 | |
| GOST 4204−77 | Sec. 2, 5 | |
| GOST 4328−77 | Sec. 2, 5 | |
| GOST 4461−77 | Sec. 2, 5 | |
| GOST 9428−73 | Sec. 5 | |
| GOST 10484−78 | Sec. 2 | |
| GOST 10929−76 | Sec. 5 | |
| GOST 11293−78 | Sec. 2 | |
6. Validity extended until
7. The re-release (may 1989) with Amendments No. 1, 2 approved in August 1984, March 1989 (IUS 12−84, 6−89)
This standard establishes a differential gravimetric and photometric methods for determination of silicon (with a mass fraction of silicon of from 1% to 15%) in silumin in pigs.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 1762.0−71.
GRAVIMETRIC METHOD
The method is based on the allocation of silicic acid after the decomposition of silumin and the determination of silicon by difference in weight before and after sludge treatment hydrofluoric acid.
(Changed edition, Rev. N 2).
2. EQUIPMENT, REAGENTS, SOLUTIONS
Sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 30%.
Sulfuric acid GOST 4204−77, diluted 1:1, 1:10.
Hydrochloric acid by the GOST 3118−77, diluted 1:1 with volume fraction of 2%.
Nitric acid GOST 4461−77.
Hydrofluoric acid according to GOST 10484−78.
Gelatin food according to GOST 11293−78*, a freshly prepared solution with a mass fraction 2%: 2 g of gelatin was placed in a conical flask with a capacity of 250 cmwith 100 cm
heated to 70 °C water and dissolve the gelatin when it is heated, not boiling.
________________
* Valid GOST 11293−89. — Note the CODE.
Bromine according to GOST 4109−79 saturated cold aqueous solution (bromine water).
Sodium carbonate according to GOST 83−79.
Sodium tetraborate 10-water according to GOST 4199−76 (dehydrated at 400 °C).
Mix for fusion: mix sodium carbonate and sodium tetraborate in a ratio of 3:1 (by weight).
A muffle furnace with thermostatic control, ensuring the heating temperature of 1000 °C.
Cup platinum, silver, Nickel.
(Changed edition, Rev. N 2).
3. ANALYSIS
3.1. Alkaline decomposition of the sample
A portion of the silumin weight of 0.5 g was placed in a platinum, silver or Nickel Cup with a capacity of not less than 100 cm, close the Cup lid, and slightly moving the lid, poured 20 cm
of the sodium hydroxide solution. At the end of the violent reaction Cup put on a sand bath and heated until the complete cessation of dissolution of the alloy, then cooled, washed cap and the walls of the Cup with a little water and then the alkali solution is diluted with 20−25 cm
of water.
After that the cold solution carefully with constant stirring, poured into a glass with a capacity of 400 cm, which is pre-filled with 40 cm
of sulphuric acid diluted 1:1, and 5 cm
of nitric acid.
Cup rinsed 2−3 times with hot water and a small amount of sulfuric acid, diluted 1:10.
The solution was evaporated prior to the selection of dense white fumes of sulphuric anhydride. After a short cooling down to 70 °C to the residue from evaporation add 5 cmof gelatin solution was mixed thoroughly with a glass rod and leave the solution for 5 min on a sand bath. Then add 100 cm
of hot water, stirred, and heated (without boiling) until the dissolution of sulfate salts. The hot solution is quickly filtered through the filter «white ribbon», washed the glass and wash the precipitate on the filter 3−4 times with a solution of hot hydrochloric acid with volume fraction of 2% and 8−10 times with hot water to remove salts.
The filter with precipitate was placed in a platinum crucible, carefully incinerated at a temperature of 400 °C and calcined at 1000 °C for 40 min, then cooled in a desiccator and weighed. To the calcined precipitate add 3−5 drops of sulfuric acid diluted 1:1, 5 cmhydrofluoric acid and evaporate the contents of the crucible on a sand bath to dryness.
After that, the residue was calcined at 1000 °C for 10 min, cooled in a desiccator and vzveshivat
yut.
3.2. The acid decomposition of the sample
A portion of the silumin weighing 0.5 g were placed in a glass with a capacity of 250 cm, 30 cm, pour the
water saturated with bromine, and 50 cm
of hydrochloric acid diluted 1:1. After reaction the glass is put on a sand bath and kept there until the end of the reaction. If necessary, add further small portions of bromine water (solution should be yellow in color).
Wash the side of the Cup with hot water and filtered off the insoluble residue through ash-free filter «blue ribbon», after adding to the filter a small amount of paper pulp.
The precipitate is washed with hot water 6−8 times. The filtrate collected in a beaker with a capacity of 250 cm, evaporated to a small volume and save.
The filter with precipitate was placed in a platinum crucible, carefully incinerated, calcined for 2−3 min at 900 °C and cooled. The residue in the crucible is mixed thoroughly with 3 g of a mixture of soda and borax, leaving a small amount of mixture to cover the contents of the crucible, and fused at a temperature of 950 °C for 15 min, pre-to withstand the crucible with the contents at a temperature of 700 °C.
After cooling, the crucible with the melt from the outside is washed with hot water, placed in a beaker with a capacity of 150 cmand leached in 30 cm
of hydrochloric acid diluted 1:1.
After complete dissolution of the melt in the crucible is washed with hot water, and the solution attached to the basic solution obtained after the decomposition of the sample in hydrochloric acid, and evaporated on a hot sand bath to wet salts.
The glass removed from the bath, add 20 cmof concentrated hydrochloric acid and mix thoroughly. Then add 5 cm
of the gelatin solution, mix again and allow to stand for 5 min.
Add hot water to a volume of approximately 60 cm, mixed to dissolve the salts (without heating) and after 3−4 min the released silicic acid is filtered through ashless filter «white ribbon». Wash the beaker and wash the precipitate on the filter 2−3 times with a solution of hot hydrochloric acid with a mass fraction of 2% and 6−8 times with hot water to remove salts. The filter with precipitate was placed in a platinum crucible and then do as described in claim 3.1.
Sec. 3. (Changed edition, Rev. N 2).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of silicon () in percent is calculated by the formula
where is the mass of the crucible with the sediment, g;
— weight of crucible with residue after sludge treatment fluoride-hydrogen and sulphuric acids, g;
— the weight of the portion of silumin, g;
0,4674 — the ratio of silicic acid on the silicon.
4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values of convergence of 0.3%, repeatability of 0.5%.
(Changed edition, Rev. N 2).
DIFFERENTIAL PHOTOMETRIC METHOD
The essence of the method consists in measuring the optical density of the colored complex compounds kremneftoristogo of heteropolyblue the reaction of silicic acid with molybdenum-acidic ammonium, followed by reduction of the complex with ascorbic acid.
5. APPARATUS, REAGENTS AND SOLUTIONS
Type photoelectrocolorimeter FEK-56M, PEC-60, KLF or spectrophotometer type SF-26, SF-16 or similar.
Neutral glass NS-8 with a thickness of 2, 3 and 4 mm.
Hydrochloric acid — according to GOST 3118−77, diluted 1:1 and 1:10.
Sulfuric acid GOST 4204−77, solutions of concentration (
H
SO
)=0,14 mol/DM
(0,14 n) and
(
H
SO
)=8 mol/DM
(8 s.). Nitric acid GOST 4461−77.
Sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 30%.
Sodium carbonate according to GOST 83−79.
Ammonium molybdate according to GOST 3765−78, a solution with a mass fraction of 5%.
Ascorbic acid, freshly prepared solution with a mass fraction of 1%.
Hydrogen peroxide according to GOST 10929−76, a solution with a mass fraction of 3%.
Silicon dioxide according to GOST 9428−73.
Standard solutions of silicon dioxide
Solution a: 0,2140 g of finely crushed in an agate or plexiglass mortar and preheated for 1 h at 1000 °C of silicon dioxide is fused in a platinum crucible with 5 g of anhydrous sodium carbonate at 900 °C for 10−15 min to obtain a transparent melt. The smelt is dissolved in water by heating in a platinum, silver or Nickel Cup. The solution was cooled, poured into a measuring flask with volume capacity of 1000 cmand topped to the mark with water; store in a polyethylene vessel.
1 cmof solution A contains 0.1 mg of silicon.
Solution B: 50 cmsolution And dilute to the mark with water in a flask with a capacity of 250 cm
and stirred; prepared prior to use.
1 cmof the solution contains 0.02 mg of silicon.
6. ANALYSIS
6.1. To the charge of silumin weight of 0.25 grams in Nickel, silver or platinum add a Cup 27 cmof sodium hydroxide, cover with a lid and dissolve in the cold. At the same time spend control experience. After the violent reaction solution in the Cup is heated on a sand bath for 15 min After cooling the solution the lid and the walls of the Cup is washed with a small amount of water and poured another 20−25 cm
of water.
The solution gradually with constant stirring, poured into a glass with a capacity of 400 cm, which is pre-poured 100 cm
of hydrochloric acid diluted 1:1, and 2 cm
of nitric acid. Cup rinsed 2−3 times with hot water, and then 10 cm
of hydrochloric acid, diluted 1:10. The solution is heated on a sand bath for 5−7 minutes before formation of a transparent solution.
If necessary for the dissolution of copper can add a few drops of hydrogen peroxide.
The cooled solution was transferred to volumetric flask with a capacity of 500 cm, is diluted to the mark with water and mix. Select aliquot part of the solution is 5 cm
in a volumetric flask with a capacity of 100 cm
, dilute the solution to 50 cm
with a solution of sulfuric acid concentration
(
H
SO
)=0,14 mol/DM
(0,14 n), pour 5 cm
of ammonium molybdate and allowed to stand 10 min. Then add 25 cm
of a solution of sulfuric acid concentration
(
H
SO
)=8 mol/DM
(8.), washed her walls, and 2−8 min through 10 cm
of ascorbic acid. Bring the solution with water to the label
and and mix.
6.2. At the same time prepare a solution of comparison. For this, 5 cmof the solution in the reference experiment is placed in a volumetric flask with a capacity of 100 cm
, add from microburette 9.0 cm
standard solution B, which corresponds to 0.18 mg of silicon, diluted the solution to 50 cm
with a solution of sulfuric acid concentration
(
H
SO
)=0,14 mol/DM
(0,14 n), pour 5 cm
of ammonium molybdate and then do as specified in clause
6.1.
6.3. The optical density of test solution is measured after 30 minutes relative to the comparison solution on the photoelectrocolorimeter or spectrophotometer, given that a maximum of light absorption of solutions corresponds to a wavelength of 815 nm. Use the permanent cuvettes (1.0 cm), one of which is designed to test fluid and the other for solution comparison. The cell must be marked.
When measuring on the spectrophotometer is solution comparisons, you can use neutral glass NS-8 with a thickness of 2, 3 or 4 mm. To do this in one of the cuvettes pour the solution in the reference experiment, and in another solution of the sample being examined and to the holder of these ditches is to put a neutral holder with stand HC-8, which is located in front of the cuvette with the solution in the reference experiment.
The optical density of solutions measured relative to glass, should be in the range from minus to plus 0,40 0,70.
In the field of mass fraction of silicon of 1−10% use glass HC-8 2.3 mm, area mass fraction of 5−15% glass HC-8 4.0 mm.
If the optical density of test solution more optical density of the solution comparison, the zero optical density is determined by the solution comparison. Then measure the optical density of test solution, recording it with a plus sign.
If the optical density of test solution less than the optical density of the solution compare, then apply reverse measurement: at zero optical density set the device on the subject to the solution and measure the optical density of the solution comparison, writing it with a minus sign.
The optical density of solutions determine the mass of silicon for the calibration schedule.
6.4. Construction of calibration curve
In a volumetric flask with a capacity of 100 cmpoured from microburette 0; 1,0; 3,0; 6,0; 9,0; 12,0; 15,0; 18,0 cm
standard solution B, which corresponds to 0; 0,02; 0,06; 0,12; 0,18; 0,24; 0,30 and 0.36 mg of silica, diluted to 50 cm
with a solution of sulfuric acid concentration
(
H
SO
)=0,14 mol/DM
(0,14 n), pour 5 cm
of ammonium molybdate and then do as indicated in the analysis.
The comparison solution is a solution containing 9.0 cmstandard solution B, or neutral glass NS-8 with a thickness of 2, 3 or 4 mm When using glass neutral glass NS-8 put the cuvette with the solution containing silicon.
According to the obtained values of optical density of solutions and the known mass of the silicon to build the calibration graph.
7. PROCESSING OF THE RESULTS
7.1. Mass fraction of silicon () in percent is calculated by the formula
where is the mass of silicon was found in the calibration graphics mg;
— the total volume of solution, cm
;
— volume aliquote part of the solution, cm
;
— the weight of the portion of silumin,
7.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in clause 4.2.
Sec. 5−7. (Added, Rev. N 2).
