GOST 11739.25-90

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  ГОСТ 11739.25-90

GOST 11739.25−90 Alloys aluminium cast and wrought. Methods for determination of scandium

GOST 11739.25−90

Group B59

STATE STANDARD OF THE USSR

ALLOYS ALUMINIUM CAST AND WROUGHT

Methods for determination of scandium

Aluminium casting and wrought alloys.
Methods for determination of scandium

AXTU 1709

Valid from 01.07.91
before 01.07.96*
_______________________________
* Expiration removed
Protocol 5−94 N Interstate Council
for standardization, Metrology and certification
(IUS N 11/12, 1994). — Note the manufacturer’s database.

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of aviation industry of the USSR

DEVELOPERS

V. G. Davydov, doctor of engineering. Sciences; V. A. Moshkin, PhD. tech. Sciences; G. I. Friedman, PhD. tech. Sciences; L. A. Tenyakova, V. A. Osipova, Cand. chem. Sciences

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 28.06.90 N 1962

3. The frequency of inspection — 5 years

4. INTRODUCED FOR THE FIRST TIME

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies the photometric (with a mass fraction of scandium of from 0.02 to 2.0%) and flame photometric (at a mass fraction of scandium of 0.1 to 5.0%) methods for determination of scandium.

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 25086 with the Supplement.

1.1.1. For the results analysis be the arithmetic mean of results of two parallel measurements.

2. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF SCANDIUM

2.1. The essence of the method

The method is based on dissolving the samples in hydrochloric acid, the formation at pH 3.5 and 3.6 raznomastnogo complex scandium-molybdenum-arsenazo III, painted in blue, and fotomaterialy at a wavelength of 675 nm. The color complex is stable during the day.

Aluminum, iron, zinc, magnesium, lithium definition does not interfere. The influence of titanium and zirconium eliminate photoretrieval of the sample solution on the background of compensating aliquote part of test solution, which in addition to all the chemicals entered the Trilon B. for the mass concentration of copper greater than 0.5% of its masked with thiourea.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

a pH meter.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cmand a solution of 1:1, 1:4, 0.1 mol/DM.

Nitric acid according to GOST 4461, density 1,35−1,40 g/cmand a solution of 0.6 mol/DM.

Acetic acid according to GOST 61, a density of 1.05 g/cmand a solution of 0.2 mol/DMdensity 1.00 g/cm: 23 cmof acetic acid with a density of 1.05 g/cmis placed in a volumetric flask with a capacity of 200 cm, made up to the mark with water and mix.

Thiourea according to GOST 6344, solution 100 g/DM.

Sodium hydroxide according to GOST 4328, solutions 2 and 0.1 mol/DM.

Sodium molybdate according to GOST 10931, solution: 25 g of sodium molybdate was dissolved in 75 cmof water and filtered through a filter medium density («white ribbon»).

The indicator methyl orange, solution 0,5 g/DM: 0.05 g of the reagent dissolved in 100 cmof water and stirred.

Arsenazo, III, a freshly prepared solution of 1 g/DM: 0.1 g of the reagent dissolved in 100 cmof water and filtered through a dense filter («blue ribbon»).

Buffer solution pH 3.5: the 2000 cmof acetic acid 0.2 mol/DMflow 300 cm0.1 mol/DMsolution of sodium hydroxide. The value of pH control on the pH meter.

Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid 2-water (Trilon B) according to GOST 10652, solution 0,1 mol/DM.

Aluminium GOST 11069* brand А999.
_______________
* On the territory of the Russian GOST 11069−2001, here and hereafter. — Note the manufacturer’s database.

Scandium oxide at MRTU 6−09−3066.

Standard solutions of scandium

Solution a: 0,7669 g of scandium oxide are dissolved in 30 cmof hydrochloric acid at a moderate heat. The cooled solution was transferred to volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.001 g of scandium.

Solution B, freshly prepared: 1 smsolution And transferred to a volumetric flask with a capacity of 100 cm, add 0.1 mol/DMsolution of hydrochloric acid to the mark and mix.

1 cmof solution B has the 0.00001 g of scandium

.

2.3. Analysis

2.3.1. A portion of the sample mass according to table.1 is placed in a conical flask with a capacity of 100 cm, carefully poured 20 cmof a hydrochloric acid solution (1:1), cover the flask with a watch glass or funnel and moderately heated to dissolve. To the solution was added dropwise nitric acid (in the presence of the sample of copper prior to its dissolution), then three drops in excess, wash the walls of the bulb approximately 10 cmof water and boil for 1−2 min.

At the same time under the same conditions dissolve 0.25 g of aluminum.

Table 1

Chilled solutions are transferred to volumetric flasks with a capacity of 100 cm, made up to the mark with water and mix.

2.3.2. Two aliquote part of the solution from the volumetric flask with a capacity of 100 cmaccording to table.1 carry in two volumetric flasks with a capacity of 50 cm(if the sample of copper poured to each aliquots of 3 cmof a solution of thiourea and incubated for 5 min), pour 15 cmof a solution of nitric acid, 10 cmof a solution of molybdate of sodium, 1 drop of methyl orange indicator, neutralise with hydrochloric acid 1:4-orange-pink colouration in case of overdose acid the appearance of bright crimson colouring is added dropwise a solution of sodium hydroxide 2 mol/DMto the orange-pink color, when the pH of the solution is equal to 3.5 and 3.6. The solution is poured 2cmof a solution of arsenazo III, topped up with buffer solution with pH 3.5 to the mark and mix

.

2.3.3. Optical density of the solution is measured after 15 min at a wavelength of 675 nm in a cuvette with a layer thickness of 10 mm Solution comparison aliquota is the second part of the test solution, which, in addition of all reagents before adding arsenazo III introduced 1 cmof solution of Trilon B.

Mass fraction of scandium are calculated according to the calibration schedule.

2.3.4. Construction of calibration curve

In five out of six volumetric flasks with a capacity of 50 cmmeasured to 0,5; 1,0; 1,5; 2,0; 2,5 cmstandard solution B, which corresponds to 0,000005; 0,00001; 0,000015; 0,00002; 0,000025 g of scandium. To all flasks add appropriate aliquot part of the solution of the aluminum and then do as indicated in the claims.2.3.2 and 2.3.3, except that during the measurement the optical density of the solution comparison is the solution containing all reagents, except standard solution scandium.

According to the obtained values of optical density of the solutions and their corresponding masses of scandium build the calibration graph.

2.4. Processing of the results

2.4.1. Mass fraction of scandium () in percent is calculated by the formula

, (1)

where is the mass of scandium in the sample solution found by the calibration schedule g;

 — the weight of the portion of the sample in aliquote part of the solution,

2.4.2. Discrepancies in the results must not exceed the values given in table.2.

Table 2

3. FLAME PHOTOMETRIC METHOD FOR THE DETERMINATION OF SCANDIUM

3.1. The essence of the method

The method is based on dissolving the sample in hydrochloric acid and subsequent measurement of the radiation intensities of the scandium at a wavelength of 607,3 nm in a flame acetylene-nitrous oxide.

3.2. Apparatus, reagents and solutions

The fiery photometer or spectrophotometer atomic absorption operating in the mode of emission.

Acetylene according to GOST 5457, cleaned with sulfuric acid.

Nitrous oxide medical.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cmand a solution of 1:1.

Nitric acid according to GOST 4461, density 1,35−1,40 g/cm.

Ammonium chloride according to GOST 3773, solution 100 g/DM.

Nickel chloride according to GOST 4038, a solution of 2 g/DM.

Aluminium GOST 11069 brand А999.

A solution of aluminum 50 g/DM: 25 g of aluminum was placed in a beaker with a capacity of 600 cm, 400 cm pouredhydrochloric acid solution and dissolved by heating, adding 1 cmof solution of chloride Nickel. The solution was cooled, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

Scandium oxide at MRTU 6−09−3066.

Standard solution scandium — solution a according to claim 2.2.

1 cmof the solution contains 0.001 g scan

Diya.

3.3. Analysis

3.3.1. A portion of sample weighing 0.5 g is placed in a conical flask with a capacity of 100 cm, carefully poured 20 cmof hydrochloric acid, cover the flask with a watch glass or funnel and moderately heated until dissolution, to the solution was added dropwise nitric acid (in the presence of the sample of copper prior to its dissolution), 3 drops in excess, wash the walls of the bulb approximately 10 cmof water and boil for 1−2 min, Cooled to room temperature, the solution was transferred to volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Aliquot part of the solution according to the table.3 is transferred to a volumetric flask with a capacity of 100 cm, add 10 cmof a solution of ammonium chloride, made up to the mark with water and mix.

Table 3

3.3.2. The solution in the reference experiment is prepared according to claim 3.3.1, using is sample the sample the sample of aluminium.

3.3.3. Construction of calibration graphs

3.3.3.1. When the mass fraction of scandium of 0.1 to 0.5% in seven volumetric flasks with a capacity of 100 cmis placed 5 cmof a solution of aluminum in six of them measure 0,25; 0,5; 1,0; 1,5; 2,0; 2,5 cmstandard solution A, which corresponds to 0,00025; 0,0005; 0,001; 0,0015; 0,002; 0,0025 g scandium, add 2 cmof hydrochloric acid solution, 10 cmof a solution of ammonium chloride.

3.3.3.2. When the mass fraction of scandium of from 0.5 to 5.0% in seven volumetric flasks with a capacity of 100 cmplaced at 1 cmof solution of aluminum in six of them measure 0,25; 0,5; 1,0; 1,5; 2,0; 2,5 cmstandard solution A, which corresponds to 0,00025; 0,0005; 0,001; 0,0015; 0,002; 0,0025 g scandium, add 2 cmof hydrochloric acid solution, 10 cmof a solution of ammonium chloride.

3.3.3.3. The solutions in flasks in PP.3.3.3.1 and 3.3.3.2 topped up to the mark with water and mix.

3.3.4. The sample solution, solution control experience and solutions to build the calibration curve is sprayed into the flame of acetylene-nitrous oxide and measure the emission intensity of scandium at a wavelength of 607,3 nm.

According to the obtained values of radiation intensity and corresponding mass concentrations of scandium build the calibration graph.

The mass concentration of scandium in the sample solution and in the solution of control and experience determined by the calibration schedule.

3.4. Processing of the results

3.4.1. Mass fraction of scandium () in percent is calculated by the formula

, (2)

where is the mass concentration of scandium in the sample solution found by the calibration schedule, g/cm;

 — mass concentration of scandium in the solution in the reference experiment, was found in the calibration schedule, g/cm;

 — the volume of the sample solution, cm;

 — the weight of the portion of the sample in aliquote part of the solution, g

.

3.4.2. Discrepancies in the results must not exceed the values given in table.2.