GOST 1762.3-71
GOST 1762.3−71 Silumin ingots. Methods for determination of calcium (with Amendments No. 1, 2)
GOST 1762.3−71
Group B59
STATE STANDARD OF THE USSR
SILUMIN IN PIGS
Methods for determination of calcium
Aluminium-silicon alloy ingots.
Methods for determination of calcium
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. IV)
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | Item number | |
| GOST 83−79 | Sec. 8 | |
| GOST 1381−73 | Sec. 2 | |
| GOST 1762.0−71 | 1.1 | |
| GOST 3118−77 | Sec. 2, 5, 8 | |
| GOST 3760−79 | Sec. 2 | |
| GOST 3773−72 | Sec. 2, 5 | |
| GOST 4038−79 | Sec. 8 | |
| GOST 4109−79 | Sec. 2 | |
| GOST 4147−74 | Sec. 2 | |
| GOST 4172−76 | Sec. 2 | |
| GOST 4204−77 | Sec. 2 | |
| GOST 4233−77 | Sec. 8 | |
| GOST 4328−77 | Sec. 2, 5, 8 | |
| GOST 4461−77 | Sec. 2 | |
| GOST 4530−76 | Sec. 5, 8 | |
| GOST 5457−75 | Sec. 8 | |
| GOST 5712−78 | Sec. 2 | |
| GOST 8864−71 | Sec. 5 | |
| GOST 9428−73 | Sec. 8 | |
| GOST 10652−73 | Sec. 5 | |
| GOST 10929−76 | Sec. 2, 8 | |
| GOST 11069−74 | Sec. 8 | |
| GOST 18300−87 | Sec. 2, 5 | |
| GOST 24363−80 | Sec. 5 | |
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 specifies the gravimetric, volumetric chelatometric and atomic absorption methods for the determination of calcium (when the mass fraction of calcium of 0.03 to 0.30%).
(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 deposition of calcium in the form of oxalate after prior separation of interfering elements and transformation of calcium oxalate to calcium sulphate.
(Changed edition, Rev. N 2).
2. REAGENTS AND SOLUTIONS
Hydrochloric acid by the GOST 3118−77, diluted 1:1, 1:2, the solution with volume fraction of 1%.
Sodium hydroxide according to GOST 4328−77, solutions with a mass fraction of 30 and 1%.
Sodium phosphate disodium GOST 4172−76, a solution with a mass fraction of 10%.
Nitric acid GOST 4461−77.
Hydrogen peroxide according to GOST 10929−76, a solution with a mass fraction of 3%.
Ammonia water according to GOST 3760−79.
Methyl red is 0.1% alcohol solution.
Ammonium chloride according to GOST 3773−72.
Ammonium oxalate according to GOST 5712−78, a saturated solution and a solution with a mass fraction of 0.1%.
Sulfuric acid GOST 4204−77, diluted 1:1.
Bromine according to GOST 4109−79, a saturated solution (bromine water).
Iron chloride according to GOST 4147−74, 0,05 n solution.
The technical rectified ethyl alcohol GOST 18300−87.
Geksametilentetramin (methenamine) technical GOST 1381−73, solutions with a mass fraction of 0.5 and 25%.
(Changed edition, Rev. N 2).
3. ANALYSIS
A portion of the silumin with a mass of 3−5 g (depending on the calcium content) were placed in a glass with a capacity of 500 cm, covered with a glass watch glass and poured in small portions 75−100 cm
of hydrochloric acid diluted 1:1. After the violent reaction solution and the precipitate are heated to the complete decomposition of the sample. Then wash the glass and the side of the Cup with hot water and filtered the solution through filter «blue ribbon», collecting the filtrate in a beaker with a capacity of 500 cm
. The filter cake was washed with hot solution with a mass fraction of hydrochloric acid 7%. At the same time spend 2−3 control experience. To a solution of the reference experiment add 4 cm
of solution of ferric chloride, which is a manifold.
To the filtrate is added five drops of hydrogen peroxide, heated to boiling and with stirring, poured a solution with a mass fraction of sodium hydroxide of 30% to dissolve the dropdown precipitate of aluminum hydroxide and 5−10 cmin excess. To the hot solution add 20 cm
of a solution with a mass fraction of sodium phosphate 10% and continue to heat for another 5 min with frequent stirring. After that, the solution is kept in a warm place until coagulation of the precipitate (the solution with the sediment can be left overnight).
The precipitate, filtered off on the filter «blue ribbon» and washed it with a solution with a mass fraction of sodium hydroxide, 1%, then the precipitate is washed with hot water, and filter back into the beaker in which to conduct the deposition. The remaining filter residue is dissolved 20−25 cmhot hydrochloric acid, diluted 1:2. If manganese is present, add a few drops of hydrogen peroxide. The filter was washed 4−5 times with hot water. The resulting solution can be used for the determination of calcium by gravimetric method or volumetric chelatometric method.
To the solution was added 10 drops of nitric acid and heated to boiling. The solution was then neutralized with ammonia prior to the deposition of hydroxides. The precipitate is dissolved with hydrochloric acid diluted 1:1, surging dropwise. For separation of manganese dioxide poured 50 cmof bromine water. To the solution add 0.5 g of ammonium chloride, 25 cm
of a solution of hexamine, with a mass fraction of 25% and heated for 20 min to coagulate the precipitate. The precipitate was filtered through a filter «white ribbon» in a conical flask with a capacity of 500 cm
. Precipitate was washed 6−8 times with a warm solution of hexamine with a mass fraction of 0.5%, washing with this solution the side of the Cup.
The filtrate was evaporated to a volume of approximately 10 cm, after cooling, poured 20 cm
of nitric acid, cover the beaker watch glass and heat the contents of the first glass gently to remove rapidly evolved oxides of nitrogen, and then dry. The remaining salts are dissolved in hydrochloric acid, diluted 1:1, and washed the glass and the side of the Cup with hot water to obtain a transparent solution. Neutralize the hot solution with ammonia until the color of methyl red indicator and add one drop in excess. If there is a precipitate, it is filtered through the filter «white ribbon». The filtrate collected in a beaker with a capacity of 150 cm
. The beaker and the filter washed with hot water.
To the solution a volume of 75−80 cmadd a few drops of hydrochloric acid diluted 1:1, heated to boiling and poured 10 cm
of a hot saturated solution of ammonium oxalate. Then under stirring added dropwise a solution of ammonia until alkaline reaction, and boil the solution until precipitation, then defend in a warm place. If necessary, add 1−2 drops of ammonia and leave for 10−12 hours.
The precipitate of calcium oxalate is filtered through filter «blue ribbon», carefully washed the glass and wash the precipitate on the filter with cold solution with a mass fraction of ammonium oxalate 1%.
The filter with precipitate was placed in a weighed platinum crucible, incinerated and calcined before complete combustion of the coal filter. The residue in the crucible is moistened with three drops of water, add 3−4 drops of nitric acid, and then 4−5 drops of sulfuric acid diluted 1:1, and gently evaporated to dryness. The residue in the crucible is calcined to constant weight at a temperature of 800 °C, cooled in a desiccator and weighed in the form of calcium sulfate.
(Changed edition, Rev. N 1, 2).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of calcium () in percent is calculated by the formula
where is the mass of the precipitate of calcium sulfate, g;
— the weight of the portion of silumin, g;
0,2944 — the ratio of calcium sulfate to calcium.
4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
| Mass fraction of calcium, % | Allowable absolute differences, % | |
| convergence |
reproducibility | |
| From 0.03 to 0.10 incl. | 0,01 | 0,02 |
| SV. Of 0.10 «to 0.30 « | 0,02 | 0,03 |
4.1, 4.2. (Changed edition, Rev. N 2).
CHELATOMETRIC METHOD
The essence of the method consists in the complexometric determination of calcium with acid chrome dark blue as indicator after prior separation of interfering elements.
5. REAGENTS AND SOLUTIONS
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 30%.
Ammonium chloride according to GOST 3773−72.
Sodium diethyldithiocarbamate according to GOST 8864−71, a solution with a mass fraction of 5%.
Paper Congo red.
Acid chrome dark blue.
The disodium salt of ethylene diamine 
(0.025 M) prepared as follows: 9,30 g Trilon B dissolved in water. If the solution is turbid, it was filtered into a measuring flask with volume capacity of 1000 cm
, then diluted to the mark with water and mix.
Calcium carbonate according to GOST 4530−76.
A standard solution of calcium molar concentration of 0.025 mol/DM(0.025 M); 2,5022 g of calcium carbonate, previously dried at 100 °C to constant weight, dissolved in 30 cm
of hydrochloric acid diluted 1:1. After that, the solution is placed in a measuring flask with volume capacity of 1000 cm
, made up to the mark with water and mix.
To determine the correction factor of the solution Trilon B 20 cmstandard solution of calcium molar concentration of 0.025 mol/DM
(0.025 M) was placed in a conical flask with a capacity of 250 cm
, dilute with water to 100 cm
, pour 3−4 drops of Indigo Carmine solution and a solution of potassium hydroxide until the color changes from Indigo blue to yellow. Then pour 4−5 cm
of potassium hydroxide, 0.1 g of acid chrome dark blue and titrate with a solution of Trilon B to switch the color of the solution from pink to blue-violet.
Correction factor () of the solution Trilon B is calculated by the formula
where — the volume of a standard solution of calcium molar concentration of 0.025 mol/l
(0,025 M), cm
;
— volume of solution Trilon B with molar concentration of 0.025 mol/l
(0,025 M), cm
.
Potassium hydroxide according to GOST 24363−80, a solution with a mass fraction of 20%.
Indigo Carmine solution with a mass fraction of 0.25% in alcohol diluted 1:1.
The technical rectified ethyl alcohol GOST 18300−87.
6. ANALYSIS
For the determination of calcium using a solution obtained in sect.3. The solution is evaporated, if necessary, to a volume of 100−150 cm, add 0.5 g of ammonium chloride, cooled, neutralized in the presence of Congo red paper with sodium hydroxide solution and hydrochloric acid diluted 1:1, until the purple color of paper of the Congo. The solution was then transferred to a volumetric flask with a capacity of 250 cm
, 30 cm, pour the
solution of sodium diethyldithiocarbamate, dilute to the mark with water and mix.
After coagulation of the precipitate the solution is filtered through a dry filter 2−3 «blue tape» in a dry flask with a capacity of 250 cm. The first portion of the filtrate discarded. Pipetted 200 cm
of the solution in a beaker with a capacity of 400 cm
, is evaporated to a volume of about 100 cm
, cooled, transferred into a flask with a capacity of 250 cm
and immediately carried out the titration of calcium with Trilon B, as described below (after some time the solution may become cloudy due to decomposition of excess sodium diethyldithiocarbamate. In the case of cloud solutions must be filtered).
During the titration the solution add 3−4 drops of Indigo Carmine solution and a solution of potassium hydroxide until the color changes from blue to yellow, then add another 4−5 cmin excess (pH =12,5−13,5). To the resulting solution was added 0.1 g of the indicator acid chrome dark blue, then titrated under constant stirring with a solution of Trilon B before transition of colouring from pink to blue-violet.
7. PROCESSING OF THE RESULTS
7.1. Mass fraction of calcium () in percent is calculated by the formula
where — volume of solution Trilon B with molar concentration of 0.025 mol/l
(0,025 M), spent on titration, sm
;
the titer of the solution Trilon B with molar concentration of 0.025 mol/DM
(0.025 M), calculated calcium, g/cm
;
— correction factor of the solution Trilon B;
— the weight of the portion of silumin,
G.
7.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
ATOMIC ABSORPTION METHOD
The essence of the method consists in measuring the atomic absorption of calcium when spraying the sample solution into the flame of acetylene-nitrous oxide at a wavelength 422,7 nm.
8. APPARATUS, REAGENTS AND SOLUTIONS
Spectrometer atomic absorption model of Perkin-Elmer, «Saturn» or similar.
Lamp with a hollow cathode, is intended for the determination of calcium.
Muffle furnace with thermostat, providing a temperature of 1000 °C.
Acetylene in cylinders for technical GOST 5457−75.
The nitrous oxide.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Hydrogen peroxide according to GOST 10929−76, a solution with a mass fraction of 3%.
Aluminum brand А999 according to GOST 11069−74*.
________________
* On the territory of the Russian Federation GOST 11069−2001. — Note the CODE.
The solution of aluminum And are 10.0 g of aluminum is placed in a beaker with a capacity of 600 cm, add 250 cm
of hydrochloric acid diluted 1:1, and dissolved under heating with adding 1 cm
of Nickel chloride. The solution was cooled, transferred to a volumetric flask with a capacity of 500 cm
, is diluted to the mark with water and mix.
1 cmof the solution contains 0.02 g of aluminium.
Silicon dioxide according to GOST 9428−73.
A solution of silicon B: 2,14 g of finely crushed in an agate or plexiglass mortar and preheated for 1 h at a temperature of 1000 °C silicon dioxide is fused in a platinum crucible with 15 g of anhydrous sodium carbonate at a temperature of 900 °C for 15 min to obtain clear water. The smelt is dissolved in water by heating in a platinum, silver or Nickel Cup. The solution was cooled, transferred into a measuring flask with volume capacity of 1000 cm, is diluted to the mark with water and mix. Solution store in a plastic container.
1 cmof the solution contains 0.001 g of silicon.
Sodium chloride according to GOST 4233−77.
A solution of sodium oxide: 190 g dried at 105 °C for 30 min. sodium chloride dissolved in water. The solution was transferred into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.
1 cmof the solution contains 0.1 g of sodium oxide.
Calcium carbonate according to GOST 4530−76.
Standard solutions of calcium.
Solution D: 2,5000 g of calcium carbonate, previously dried at 105 °C to constant weight, dissolved in 50 cmof hydrochloric acid diluted 1:1. After this, the solution was transferred into a measuring flask with volume capacity of 1000 cm
, is diluted to the mark with water and mix.
1 cmof solution e contains 0.001 g of calcium.
Solution: pipetted 10 cmof solution D in a volumetric flask with a capacity of 200 cm
, adjusted to the mark with water and mix; prepare before use.
1 cmof solution E contains 0.05 mg of calcium.
Sodium carbonate according to GOST 83−79.
Sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 30%.
Methyl orange, solution with a mass fraction of 0.1%.
Nickel chloride according to GOST 4038−79, a solution with a mass fraction of 0.2%.
9. ANALYSIS
9.1. Weighed samples of the silumin weighing 0.5 g were placed in a glass with a capacity of 250 cmand poured 20 cm
of the sodium hydroxide solution. At the end of the reaction the solution is heated on a sand bath until complete dissolution of the alloy, adding 100 cm
of water and carefully pour 50 cm
of hydrochloric acid diluted 1:1. The solution is heated to enlightenment, add 1 cm
of hydrogen peroxide and boiled for 3−5 min for the destruction of its excess.
The solution was cooled and transferred to volumetric flask with a capacity of 250 cm, was adjusted to the mark with water and mix.
For the determination of calcium in a sample solution is sprayed into the flame nitrous oxide-acetylene and measure the absorbance at the wavelength of the 422,7 nm.
At the same time through all stages of the analysis carried out control experience with the addition of 20 cmof a solution of aluminium A.
Mass fraction of calcium is determined according to the calibration schedule given in the reference experiment
.
9.2. Construction of calibration curve
In seven volumetric flasks with a capacity of 250 cmflow sequentially through 12.5 cm
of solution A with 7 cm
of solution and accordingly 0; 2,5; 5,0; 7,5; 10,0; 15,0; 20,0 cm
of solution E, which corresponds to 0; 0,025; 0,050; 0,075; 0,10; 0,15 and 0.20% mass fraction of calcium.
To the solution add 100 cmof water and slowly with careful stirring at 25 cm
of solution B. Then add 3−4 drops of methyl orange indicator and drop hydrochloric acid diluted 1:1, until the color changes of the indicator in red.
Then the solutions in the flasks was adjusted to the mark with water and mix.
The prepared solutions photometrist on atomic absorption spectrometer simultaneously with the sample solution as in claim 9.1.
According to the obtained values of atomic absorption solutions and the known weight fractions of calcium build the calibration graph.
10. PROCESSING OF THE RESULTS
10.1 Mass fraction of calcium in the cent find for the calibration schedule.
10.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
Sec. 5−10. (Added, Rev. N 2).
