GOST 1762.2-71
GOST 1762.2−71 Silumin ingots. Methods for determination of iron (with Amendments No. 1, 2, 3)
GOST 1762.2−71
Group B59
STATE STANDARD OF THE USSR
SILUMIN IN PIGS
Methods of iron determination
Aluminium-silicon alloy ingots.
Methods for determination of iron
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 (sect.III)
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | Item number | |
| GOST 83−79 | Sec. 5 | |
| GOST 199−78 | Sec. 2 | |
| GOST 1762.0−71 | 1.1 | |
| GOST 3118−77 | Sec. 2, 5 | |
| GOST 4038−79 | Sec. 5 | |
| GOST 4233−77 | Sec. 5 | |
| GOST 4328−77 | Sec. 2, 5 | |
| GOST 4461−77 | Sec. 2, 5 | |
| GOST 5456−79 | Sec. 2 | |
| GOST 5457−75 | Sec. 5 | |
| GOST 9428−73 | Sec. 5 | |
| GOST 10929−76 | Sec. 5 | |
| GOST 11069−74 | Sec. 5 | |
| GOST 13610−79 | Sec. 2, 5 | |
6. Validity extended until
7. The re-release (may 1989) with Amendments No. 1, 2, 3, approved in July 1979, August 1984, March 1989 (IUS 8−79, 12−84, 6−89)
This standard sets the photometric and atomic absorption methods for the determination of iron (at mass fraction of iron from 0.15 to 1.0%) 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.
PHOTOMETRIC METHOD
The method is based on measuring the optical density of the colored in orange-red complex compound of iron (II) with on-fenantrolina or ,
-dipyridylium after pre-reduction of iron with hydroxylamine hydrochloride to ferrous state.
(Changed edition, Rev. N 2).
2. APPARATUS, REAGENTS AND SOLUTIONS
Type photoelectrocolorimeter FEK-56M, PEC-60, KLF or spectrophotometer type SF-26, SF-16 or similar.
Sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 30%.
Hydrochloric acid by the GOST 3118−77 and diluted 1:1.
Sodium acetate according to GOST 199−78, a solution with a mass fraction of 25%; prepared as follows: 250 g of the crystalline salt is dissolved in water, filtered and diluted with water to 1 DM.
Hydroxylamine hydrochloride according to GOST 5456−79, a freshly prepared solution with a mass fraction of 10%.
Orthophenanthroline, a solution with a mass fraction of 0.25%; prepared as follows: 0.25 g of reagent was dissolved with mild heating in 100 cmof water.
,
-dipyridyl, a solution with a mass fraction of 0.25%:
0.25 mg of the reagent was dissolved with mild heating in 100 cmof water.
Nitric acid GOST 4461−77 diluted 1:1.
Carbonyl iron according to GOST 13610−79.
Standard iron solution
Solution a: 1,0000 g iron is dissolved in 20 cmof hydrochloric acid diluted 1:1. At the end of the dissolution pour 1−2 cm
of nitric acid, diluted 1:1, for oxidation of iron and evaporated up to wet salts. Salt is dissolved in 20 cm
of hydrochloric acid diluted 1:1, and the solution is transferred into a measuring flask with volume capacity of 1000 cm
, made up to the mark with water and mix.
1 cmof the solution contains 1 mg of iron.
Solution B is prepared (before application): 25 cmsolution And transferred with a pipette into a measuring flask with a capacity of 500 cm
, is poured 10 cm
of hydrochloric acid diluted 1:1, made up to the mark with water and mix.
1 cmof the solution contains 0.05 mg of iron.
(Changed edition, Rev. N 2, 3).
3. ANALYSIS
3.1. A portion 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. After the violent reaction solution is heated until complete dissolution of the alloy is diluted with water and cautiously add 50 cm
of hydrochloric acid diluted 1:1. The solution is heated to enlightenment. The cooled solution was transferred to volumetric flask with a capacity of 250 cm
, made up to the mark with water and mix.
Depending on the iron content taken aliquot part 10−25 cmin a volumetric flask with a capacity of 100 cm
. The solution is diluted with water to 50 cm
, pour 5 cm
of a solution of hydroxylamine, 10 cm
of a solution of sodium acetate (the paper of the Congo in this case red) and 10 cm
solution orthophenanthroline or
,
-dipyridyl. The solution was diluted to the mark with water, mix and after 30 min measure the optical density on the photoelectrocolorimeter or spectrophotometer, given that a maximum of light absorption of solutions corresponds to a wavelength of 510 nm.
Solution comparison is water.
At the same time through all stages of the analysis spend control experience.
The optical density of test solution given in the reference experiment to determine the mass of iron in grams calibration
the Afik.
3.2. Construction of calibration curve
In seven volumetric flasks with a capacity of 100 cmplaced 0; 1,0; 2,0; 3,0; 4,0; 5,0; 6,0 cm
standard solution B, which corresponds to 0; 0,05; 0,10; 0,15; 0,20; 0,25 and 0.30 mg of iron and dilute with water to 50−60 cm
. Then add 5 cm
of the hydrochloride, 10 cm
of a solution of sodium acetate, 5 cm
solution orthophenanthroline or
,
-dipyridyl topped up to the mark with water, mix and then carry out the analysis as described in section 3.1. Solution comparison is the solution in which iron was not added.
On the found values of optical density and the known masses of iron in the solutions to build the calibration graph.
(Changed edition, Rev. N 3).
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of iron () in percent is calculated by the formula
where is the mass of iron 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,
4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
| Mass fraction of iron, % | Allowable absolute differences, % | |
| convergence | reproducibility | |
| From 0.15 to 0.40 incl. | 0,02 | 0,03 |
| SV. Of 0.40 «to 1.00 « | 0,03 | 0,04 |
(Changed edition, Rev. N 2).
ATOMIC ABSORPTION METHOD
The method is based on measuring atomic absorption of iron when spraying the sample solution into the flame of acetylene-air at a wavelength of 248,8 nm.
5. APPARATUS, REAGENTS AND SOLUTIONS
Spectrometer atomic absorption model of Perkin-Elmer, «Saturn» or similar.
Lamp hollow cathode, is intended for the determination of iron.
Muffle furnace with thermostat, providing a temperature of 1000 °C.
Acetylene in cylinders for technical GOST 5457−75.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Nitric acid GOST 4461−77 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 9428−78*.
_________________
* Probably, the error of the original. Should read GOST 9428−73. — Note the CODE.
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 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; store in a polyethylene vessel.
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.
Iron in the form of wire or carbonyl GOST 13610−79.
Standard iron solution
Solution D: 0,5000 g of iron dissolved in 15 cmof hydrochloric acid diluted 1:1. At the end of the dissolution pour 1−2 cm
of nitric acid, diluted 1:1, for oxidation of iron and evaporated up to wet salts. Salt is dissolved in 10 cm
of hydrochloric acid diluted 1:1, and transfer the solution into a measuring flask with a capacity of 500 cm
, made up to the mark with water and mix; prepare before use.
1 cmof solution e contains 0.001 g of iron.
Solution: pipetted 50 cmof solution D in a volumetric flask with a capacity of 100 cm
, adjusted to the mark with water and mix; prepare before use.
1 cmof solution E contains 0.5 mg of iron;
Sodium carbonate according to GOST 83−79.
Sodium hydroxide according to GOST 4328−77, a solution with a mass fraction of 30%.
Nickel chloride according to GOST 4038−79, a solution with a mass fraction of 0.2%.
Methyl orange, solution with a mass fraction of 0.1%.
6. ANALYSIS
6.1. 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 alloy, add 70−80 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 iron determination, the sample solution is sprayed in air-acetylene flame of the spectrometer and measure the absorbance at the wavelength of 248,8 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 iron determined by a calibration graph with reference experiment
.
6.2. 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; 1,0; 1,5; 2,5; 5,0; 7,5; 10,0 cm
of solution E, which corresponds to 0; 0,10; 0,15; 0,25; 0,50; 0,75; 1,0% the mass fraction of iron.
The solutions were diluted with water to 100 cmand slowly with careful stirring poured in 25 cm
of a solution, 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 indicated in claim 6.1.
According to the obtained values of atomic absorption solutions and the known weight fractions of iron to build the calibration graph.
7. PROCESSING OF THE RESULTS
7.1. Mass fraction of iron in the cent find for the calibration schedule.
7.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
Sec. 5−7. (Added, Rev. N 3).
