GOST 23859.2-79
GOST 23859.2−79 heat-resistant Bronze. Methods for determination of silicon (with Amendments No. 1, 2)
GOST 23859.2−79
Group B59
INTERSTATE STANDARD
BRONZE HIGH-TEMPERATURE
Methods for determination of silicon
Bronze fire-resistance. Methods for the determination of silicon
AXTU 1709
Date of introduction 1981−01−01
Resolution of the USSR State Committee for standards, dated 16 October 1979, N 3937 time of the introduction set with 01.01.81
Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)
EDITION with Amendments No. 1, 2 approved in June 1985, March 1990 (IUS 9−85, 7−90).
This standard specifies a gravimetric, photometric methods for determination of silicon (with a mass fraction of silicon of from 0.1 to 0.9%) and extraction-photometric method for the determination of silicon (with a mass fraction of silicon of from 0.005 to 0.1%) in high-temperature copper alloys.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements — according to GOST 25086−87 with the addition of a GOST 23859.1−79, sec. 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 isolation of silicon in the form silicic acid, the calcination of the precipitate to silicon dioxide and the subsequent removal of silicon in the form of the tetrafluoride. The silicon content calculated by the mass difference of sludge before and after treatment with hydrofluoric acid.
2.2. Reagents and solutions
Nitric acid GOST 4461−77.
Sulfuric acid GOST 4204−77, diluted 1:1 and 1:4.
Hydrochloric acid by the GOST 3118−77 and diluted 1:100.
Hydrofluoric acid (hydrofluoric) according to GOST 10484−78.
The mixture of acids to dissolve: to mix one part of concentrated nitric acid with two parts of concentrated hydrochloric acid.
Potassium ferrocyanide according to GOST 4207−75, a solution of 30 g/DM.
Potassium, anhydrous sodium carbonate according to GOST 4332−76.
2.3. Analysis
The weight of bronze weight 2 g at a mass fraction of silicon of from 0.1 to 0.5% and 1 g when the mass fraction of from 0.4 to 0.9% is placed in a beaker with a capacity of 300 cm, 30 cm, pour the
mixture of acids, cover with a watch glass and dissolved under heating. Once dissolved, rinse the glass and walls of beaker with water, add 20 cm
of sulphuric acid diluted 1:1, and is evaporated prior to the allocation of white smoke of sulfuric acid.
After cooling, rinse walls of beaker with water and repeat the evaporation to start the selection of a white smoke of sulfuric acid. The residue is cooled, add 3−5 cmof concentrated hydrochloric acid, 150−200 cm
of water and heated until complete dissolution of salts. Filtered the precipitated sludge on the filter medium density and is washed with hot hydrochloric acid, diluted 1:100, 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 evaporated prior to the allocation of white smoke of sulfuric acid.
After cooling, the side of the Cup and rinse and repeat the evaporation to start the selection of a white smoke of sulfuric acid. After cooling, add 150−200 cmof water, heated until complete dissolution of the salts and filtered. The filter cake is washed as described above. Both sludge along with the filter placed in a platinum crucible, dried, gradually bugleweed to avoid the formation of silicon carbide, incinerated and calcined at 1000−1100 °C to constant weight. To the calcined precipitate add 1−2 drops of water, 1 cm
hydrofluoric acid, 2−3 drops of concentrated sulphuric acid, carefully evaporated to dryness and the residue calcined at 1000−1100 °C for 15−25 min. After cooling in the desiccator the crucible is weighed again.
If after the removal of the silicon dioxide of the crucible remains a black precipitate, it is fused with anhydrous potassium carbonate-sodium at 1000−1100 °C. the Crucible was placed in a beaker with a capacity of 300 cm, add 25−30 cm
of sulphuric acid, diluted 1:4, and dissolve the melt by heating. The crucible is removed, rinse it with water, and the solution is evaporated to release a thick white smoke of sulfuric acid. After cooling, pour 150−200 cm
of hot water and heated until complete dissolution of salts. Filtered the precipitated sludge on the filter medium density and then do as above.
At the same time through the analysis of spend control experience and found the silicon content, enter the appropriate SOCA
avku.
2.2, 2.3. (Changed edition, Rev. N 1, 2).
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. Discrepancies in the results of three parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence), calculated according to the formula
where — mass fraction of silicon, %.
(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 calculated according to the formula
where — mass fraction of silicon, %.
2.4.4. Control of accuracy of analysis results is carried out according to State standard samples of high-temperature (chromium) bronze in accordance with GOST 25086−87.
2.4.3,
2.5. Method is used when the differences in quality assessment of high-temperature bronzes.
(Added, Rev. N 2).
3. PHOTOMETRIC METHOD FOR DETERMINATION OF SILICON
3.1. The essence of the method
The method is based on the formation of silicon yellow molybdosilic acid and measuring the optical density of colored solution.
3.2. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter.
a pH meter.
Nitric acid GOST 4461−77 and diluted 1:2 and 2:1.
Hydrochloric acid by the GOST 3118−77.
Sulfuric acid GOST 4204−77, diluted 1:3 and 1:99.
A mixture of hydrochloric and nitric acids in the ratio 2:3.
Hydrofluoric acid according to GOST 10484−78.
Boric acid according to GOST 18704−78, saturated solution: about 60 g boric acid dissolve in 1 DMof hot water and cooled to room temperature.
Ammonia water according to GOST 3760−79 diluted 1:1.
Ammonium molybdate according to GOST 3765−78, recrystallized, solution 50 g/DM. Carry out the recrystallization of ammonium molybdate in 250 g of ammonium molybdate was dissolved in 400 cm
of water when heated to 70−80 °C, add ammonia solution until a clear smell and the hot solution is filtered twice through the same dense filter into a glass contains 300 cm
of ethyl alcohol. The solution was cooled to 10 °C and allowed to settle for 1 h. Precipitated crystals are filtered off on a Buchner funnel under vacuum created a water vacuum pump. The crystals are washed 2−3 times with ethanol in batches of 20−30 cm
and dried in air.
Rectified ethyl alcohol GOST 18300−87.
Potassium-sodium carbonate according to GOST 4332−76.
Silicon dioxide according to GOST 9428−73.
Standard solution silicon: 0,2143 g of calcined silicon dioxide is fused in a platinum crucible with 2 g of sodium-potassium carbonate. The smelt is leached with water, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix. The solution was immediately transferred into a plastic vessel.
1 cmof the solution contains 0.0002 g of silicon
.
3.3. Analysis
3.3.1. The sample of bronze with a weight of 1 g (in mass fraction of silicon of from 0.1 to 0.5%) and 0.5 g (when the mass fraction of silicon of more than 0.5%) was placed in a polyethylene or Teflon, or Teflon beaker with a capacity of 100 cm, add 30 drops of hydrofluoric acid, 10−15 cm
of the mixture of acids, cover with plastic or Teflon cap and dissolve in the cold (leave overnight), and then in a water bath heated to 60 °C and kept at this temperature for 20−30 min, then open the lid and keep for another 15 min. After dissolution, the solution was cooled, added 30 cm
boric acid, after 20 min the mixture is transferred through a polyethylene funnel into a measuring flask with a capacity of 100 cm
containing 30 cm
of boric acid, made up to the mark with water and mix. The solution is immediately transferred into the glass, which had a dissolution. Aliquot part of the solution was 10 cm
were placed in a glass with a capacity of 50 cm
, add 10 cm
sulphuric acid (1:99), 5 cm
of ammonium molybdate solution and set pH=1,0−1,2 in pH-meter, using a solution of ammonia or boiled nitric acid (1:2). In a solution with pH=1,0−1,2 add 10 cm
sulphuric acid (1:3), transfer the solution into a volumetric flask with a capacity of 50 cm
, top up to the mark with water and mix. After 15 min measure the optical density on a photoelectrocolorimeter with a purple filter or on a spectrophotometer at 400 nm in a cuvette with the thickness of absorptive layer 5, see the quality of the solution comparison solution is used in the same sample without added molybdate of ammonium.
The obtained values of optical density subtract the value of optical density of control experiment through all stages of analysis and are measured relative
water.
3.3.2. Construction of calibration curve
Six polyethylene or Teflon, or PTFE beakers with a capacity of 50 cmis placed 0; 0,5; 1,0; 1,5; 2,0 and 2,5 cm
standard solution silicon solutions diluted with water to 10 cm
, add 10 cm
sulphuric acid (1:99) and 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 in the solution of the sample, was found in the calibration schedule g;
— the mass of silicon in the solution in the reference experiment, was found in the calibration schedule g;
— the weight of the portion corresponding to aliquote part of the solution,
3.4.2. Discrepancies in the results of three parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence), calculated according to the formula
where — mass fraction of silicon in the alloy, %.
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 calculated according to the formula
where — mass fraction of silicon in the alloy, %.
3.4.4. Control of accuracy of analysis results is carried out according to State standard samples of heat-resistant (CR) bronze in accordance with GOST 25086−87.
Sec. 3. (Changed edition, Rev. N 2).
4. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF SILICON
4.1. The essence of the method
The method is based on the formation kremneftoristogo acid, extraction of its butyl alcohol, the recovery in the extract to kremneftoristogo blue and measuring the intensity of the resulting color.
4.2. Apparatus, reagents and solutions
Spectrophotometer or photoelectrocolorimeter.
a pH meter.
Nitric acid GOST 4461−77 and diluted 1:2 (boiled).
Sulfuric acid according to GOST 4207−75 diluted 1:9.
Hydrochloric acid by the GOST 3118−77 and diluted 1:1.
A mixture of hydrochloric and nitric acids concentrated in the ratio 2:3.
Hydrofluoric acid, OS.h.
Citric acid according to GOST 3852−93, a solution of 500 g/DM.
Boric acid according to GOST 9656−75, a saturated solution, prepared as specified in section 3.2.
Ammonia is water-based.h. according to GOST 3760−79 diluted 1:1 and 1:1000.
Ammonium molybdate according to GOST 3765−78, recrystallized, solution 100 g/DM. The recrystallization is carried out, see claim 3.2.
Rectified ethyl alcohol GOST 18300−87.
Tin dichloride on the other 6−09−5384−88, a solution of 100 g/DM, cook: 10 g of tin dichloride dissolved in 100 cm
of hydrochloric acid (1:1) when heated to 80−90 °C.
Wash solution: to 50 cmof sulphuric acid are added 1.5 cm
of a solution of molybdate of ammonium.
Sodium hydroxide according to GOST 4328−77, solution 0,1 mol/DM.
Sodium carbonate according to GOST 83−79, a solution of 50 g/DM.
Sodium meta silicate on the other 6−09−5337−87.
Normal butyl alcohol according to GOST 6006−78.
Silicon dioxide according to GOST 9428−73.
Standard solutions of silicon
Preparation of silicate of sodium: 0.5 g sodium silicate dissolved in 20 cmof sodium carbonate solution in a platinum plate, cooled, placed in a plastic vessel, dilute with water to 500 cm
and mixed.
1 cmof the solution contains 0.001 g of silicon.
The exact content of the set of silicon by gravimetric method.
Preparation of silicon dioxide
Solution a: 0,2143 g of calcined silicon dioxide is fused in a platinum crucible with 2 g of sodium-potassium carbonate. The smelt is leached with water, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water, mixed and immediately transferred to a plastic vessel.
1 cmof the solution contains 0.0002 g of silicon.
The exact content of the set of silicon by gravimetric method.
Solution B: 25 cmsolution And placed in a volumetric flask with a capacity of 50 cm
, top up to the mark with sodium hydroxide solution and stirred. The solution was immediately transferred into a plastic vessel.
1 cmof solution B contains 0,0001
g silicon.
4.3. Analysis
4.3.1. Weighed bronze (see table) was placed in a polyethylene or Teflon or Teflon beaker with a capacity of 100 cm, add 30 drops of hydrofluoric acid, 15 cm
acid mixtures, cover with plastic or Teflon cap and dissolve in the cold (leave overnight), and then in a water bath heated to 60 °C and kept at this temperature for 20−30 min, then open the lid and keep for another 15 min. After dissolution, the solution was cooled, added 30 cm
boric acid, after 20 min the mixture is transferred through a polyethylene funnel into a measuring flask with a capacity of 100 cm
containing 30 cm
of boric acid, made up to the mark with water and mix. The solution is immediately transferred into the glass, which had a dissolution.
| Mass fraction of silicon, % | The mass of charge, g | The volume aliquote part of the solution, cm |
The weight of the portion corresponding to aliquote part of the solution, g |
| From 0.005 to 0.01 incl. |
1 |
50 | 0,5 |
| SV. The 0.01 «to 0.025 « |
0,5 | 20 | 0,1 |
| «Of 0.025» to 0.05 « |
0,5 | 10 | 0,05 |
| «0,5» 0,01 « |
0,25 | 10 | 0,025 |
Pre-set pH in solutions alikvotnih parts in pH-meter: in a polyethylene beaker with a capacity of 50 cmis placed aliquot part of the solution (see table). add water to a volume of 50 cm
and using ammonia solution (hos.h.) set pH=1,0−1,2 by adding ammonia solution drop by drop, recording the number of drops consumed to the surgery. Aliquot part of the solution (see table) for analysis is placed in a separating funnel with a capacity of 200 cm
, add water up to 50 cm
and set pH=1,0−1,2 using preliminary data. To the solution was dropwise added with stirring 5 cm
of ammonium molybdate solution and allowed to stand 10 min. Then add 5 cm
of citric acid, 10 cm
boiled nitric acid (1:2), 30 cm
butyl alcohol and extracted kriminalistov the heteropolyacid, carefully turning the funnel 30. After separation the aqueous layer is discarded and to the organic layer add 50 cm
wash liquid and washed, the funnel inverting 10−15 times. The aqueous layer is discarded and the organic is transferred to a volumetric flask with a capacity of 50 cm
, add butyl alcohol, 7−8 drops of solution of tin dichloride, made up to the mark butyl alcohol and vigorously shaken. Within 5 min, measure the optical density of the solution on a photoelectrocolorimeter with a red light filter (
=600−630 nm) or on a spectrophotometer at 635 nm in a cuvette with a thickness of absorbing layer 1 cm as a solution of comparison, using butyl alcohol. At the same time through all stages of the analysis carried out control experience and found in it the value of optical density is subtracted from the value of optical density of p
robe.
4.3.2. Construction of calibration curve
Five of six plastic, Teflon or Teflon cups were placed 1,0; 2,0; 3,0; 4,0 and 5,0 cmstandard solution silicon (0.0001 g/cm
). All cups add 15 drops of hydrofluoric acid, 7−8 cm
of the mixture of acids, placed in a water bath, heated to 60 °C and then are received as specified in clause
Aliquota part of the solution taken for measurement, for each point of calibration curve is 10 cm.
As a solution comparison, using a solution not containing silicon.
Calibration curve is based on its mass fraction in aliquote part of the solution.
4.4. Processing of the results
4.4.1. Mass fraction of silicon () in percent is calculated by the formula
where is the mass of silicon in the sample was found in the calibration schedule g;
— the mass of silicon in the solution in the reference experiment, was found in the calibration schedule g;
— the weight of the portion corresponding to aliquote part of the solution,
4.4.2. Discrepancies in the results of three parallel definitions should not exceed the values permitted by the divergence (
the rate of convergence), calculated according to the formula
where — mass fraction of silicon in the alloy, %.
4.4.3. 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 calculated according to the formula
where — mass fraction of silicon in the alloy, %.
4.4.4. Control of accuracy of analysis results is carried out according to State standard samples of heat-resistant (CR) bronze or by a method of additives in accordance with GOST 25086−87.
Sec. 4. (Added, Rev. N 2).
