GOST 12697.13-90

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  ГОСТ 12697.13-90

GOST 12697.13−90 Aluminium. Methods for the determination of gallium

GOST 12697.13−90

Group B59

INTERSTATE STANDARD

ALUMINIUM

Methods for the determination of gallium

Aluminium. Methods for the determination of gallium

ISS 77.120.10
AXTU 1709

Date of introduction 1991−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of metallurgy of the USSR

DEVELOPERS

T. I. Zhilina, N. Ponomareva, I. M. Kozlovskaya

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 10.12.90 N 3085

3. The standard fully complies ST SEV 6737−89

4. INTRODUCED FOR THE FIRST TIME

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. REISSUE


This standard specifies methods for the determination of gallium in aluminum: photometric when the mass fraction of gallium from 0.001 to 0.1%, and atomic absorption for the mass concentration of gallium from 0.01 to 0.1%.

1. GENERAL REQUIREMENTS

General requirements for methods of analysis GOST 12697.1.

2. PHOTOMETRIC METHOD

2.1. The essence of the method

The method is based on dissolving the samples in hydrochloric acid, the formation of blue-green gallium ion associate with malachite green in hydrochloric acid medium with concentration of 6.0−6.5 mol/DM, the extraction of the ion associate with benzene and subsequent measurement of optical density at a wavelength of 635 nm.

2.2. Apparatus, reagents and solutions

Type photoelectrocolorimeter FEK-56M, PEC-60, KLF or spectrophotometer type SF-16, SF-26 or similar type.

Hydrochloric acid according to GOST 3118, diluted 1:1 and 1:3.

Nickel (II) chloride according to GOST 4038, a solution with a mass fraction of 0.2%.

Titanium trichloride.

Titanium sponge grade TG-100 GOST 17746.

Chloride titanium: 4.65 g of titanium was placed in a conical flask with a capacity of 250 cm, and dissolved in 100 cmof hydrochloric acid (1:1) with moderate heating. The solution was cooled, poured into a volumetric flask with a capacity of 100 cm, made up to the mark with hydrochloric acid (1:1) and stirred. Store the solution in dark place in a tightly closed bottle or vessel made of dark glass.

Malachite green (tetramethyl-4,4'-diamino-triphenyl-carbonyl chloride), a solution of 20 g/DM: 2 g of finely powdered malachite green dissolved in 100 cmof hydrochloric acid (1:3) and the solution was filtered. Solution stored in a vessel made of dark glass.

Benzene according to GOST 5955.

Sodium sulfate according to GOST 4166.

Gallium (III) oxide (GaO).

Gallium technical GOST 12797.

Standard solutions of gallium.

Solution a: 1,0000 g of gallium or 1,3442 g pre-calcined at a temperature of 300 °C and cooled in a desiccator gallium oxide (III) is dissolved in 50 cmof hydrochloric acid (1:1) solution is transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

1 cmof solution A contains 1.0 mg of gallium.

Solution B: 5.0 cmmortar And placed in a measuring flask with volume capacity of 1000 cm, made up to the mark with hydrochloric acid (1:1). The solution is prepared before use.

1 cmof a solution contains 0.005 mg of gallium.

Solution: 20.0 cmof a solution is placed in a volumetric flask with a capacity of 100 cm, made up to the mark with hydrochloric acid (1:1) and stirred.

1 cmof the solution contains 0,001

mg gallium.

2.3. Analysis

2.3.1. A portion of the sample weighing 1 g is placed in a beaker with a capacity of 400 cmadd 30 cmof hydrochloric acid (1:1) and covered with a watch glass. After the cessation of the violent reaction of the glass with the solution gently warmed until complete dissolution of the sample, then wash a watch glass a small amount of water in a beaker and the solution is evaporated to wet salts. After cooling, to the residue add hydrochloric acid (1:1) in an amount according to table.1 depending on the mass fraction of gallium and heated to obtain a transparent solution. The solution was cooled, transferred to a volumetric flask with a capacity according to table.1, rinsing the beaker with hydrochloric acid (1:1), then the same acid solution made up to the mark and mix.

Table 1

If necessary, the sample solution was filtered through a dry filter, the average density in the dry beaker, rejecting the first portions of the filtrate. From the sample solution or its filtrate is taken aliquot part of 5 cmand transferred to a dry separatory funnel with a capacity of 100 cm.

To the solution in separating funnel add 1 cmof hydrochloric acid to 0.5 cmof a solution of titanium chloride (III), shaken for 1 min, then leave for 2−3 min. To the solution add 2.0 cmof a solution of malachite green, mix, add 20.0 cmof benzene and shaken for 2 min. After the separation of the aqueous phase is discarded and the organic phase was transferred into a dry volumetric flask with a capacity of 25 cm, top up to the mark with benzene and mix, then add 0.2 g of sodium sulfate and shaken to obtain a transparent solution.

Measure the optical density of the extract at a wavelength of 635 nm. Solution comparison is the extract of the reference experiment, carried out simultaneously through all stages of the analysis.

The weight of gallium in the sample solution determined by calibration schedule

.

2.3.2. To build a calibration curve in five of the six separatory funnels with a capacity of 100 cmis placed in the mass fraction of gallium less than 0.005% 1,0; 2,0; 3,0; 4,0 and 5,0 cmstandard solution, which corresponds to 0,001; 0,002; 0,003; 0,004 and 0,005 mg of gallium, gallium for the mass concentration of more than 0.005% 0,50; 1,0; 2,0; 3,0 and 4,0 cmstandard solution B, which corresponds to 0,0025; 0,005; 0,010; 0,015 and 0,020 mg gallium. In all separating funnels, add such an amount of hydrochloric acid (1:1) to the volume of the solution in the funnel was 5 cm, then do according to claim 2.3.1. Solution sixth flask containing a standard solution of gallium, is solution comparisons when constructing the calibration curve.

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

2.4. Processing of the results

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

,

where is the mass of gallium in the sample solution found by the calibration schedule, mg;

 — the weight of the portion of the sample corresponding to aliquote part of the sample solution,

2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.2.

Table 2

3. ATOMIC ABSORPTION METHOD

3.1. The essence of the method

The method is based on dissolving the sample in hydrochloric acid and measuring the nuclear absorption of gallium at a wavelength of 287,4 nm in a flame acetylene — nitrous oxide.

3.2. Apparatus, reagents and solutions

Spectrophotometer atomic absorption model of Perkin-Elmer, Saturn or similar type with a radiation source for gallium and burner for flame acetylene — nitrous oxide.

Water, double-distilled.

Acetylene in cylinders for technical GOST 5457.

The nitrous oxide.

Hydrochloric acid according to GOST 3118, diluted 1:1.

Nitric acid according to GOST 4461.

Nickel (II) chloride according to GOST 4038, a solution with a mass fraction of 0.2%.

Hydrogen peroxide according to GOST 10929.

Acetone according to GOST 2603.

Aluminum brand А999 according to GOST 11069, shavings. Immediately before use, the chips are cleaned in a small amount of hydrochloric acid solution, washed with water, acetone, dried in a drying Cabinet at 100 °C for 2−3 min and cooled in a desiccator.

A solution of aluminum 20 g/DM: 10 g of aluminum is placed in a beaker with a capacity of 600 cm, is added in small portions with 300 cmof a hydrochloric acid solution and dissolved by heating, adding 1 cmof a solution of Nickel chloride. The solution was cooled, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

Gallium metal according to GOST 12797.

Gallium (III) oxide (GaO).

Standard solutions of gallium

Solution a: 1,0000 g of gallium or 1,3442 g of gallium oxide, pre-calcined at a temperature of 300 °C and cooled in a desiccator, dissolved in 50 cmof a hydrochloric acid solution with addition of 1−2 drops of nitric acid, the solution transferred to a volumetric flask with a capacity of 1000 cm, made up to the mark with water and mix.

1 cmof solution A contains 1.0 mg of gallium.

Solution B: 10.0 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof a solution contains 0.1 mg

gallium.

3.3. Analysis

3.3.1. A portion of the sample weighing 1 g is placed in a beaker with a capacity of 400 cmand poured in small portions 30 cmof a hydrochloric acid solution. After the cessation of the violent reaction of the glass with the solution and gently warmed a few drops of hydrogen peroxide solution. After dissolution, the excess hydrogen peroxide is removed by boiling. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

The solution in the reference experiment is prepared using, instead of sample of sample weighed aluminum brand А999.

3.3.2. To build a calibration curve in six of the seven volumetric flasks with a capacity of 100 cmis placed 1,0; 2,0; 4,0; 6,0; 8,0 and 10,0 cmstandard solution B, which corresponds to 0,1; 0,2; 0,4; 0,6; 0,8 and 1,0 mg of gallium. To all flasks add 50 cmof a solution of aluminum, made up to the mark with water and mix.

Measure the atomic absorbance of gallium in the sample solution, the solution control experience and solutions to build a calibration curve at a wavelength of 287,4 nm in a flame acetylene — nitrous oxide.

From the obtained values of atomic absorption solutions containing a standard solution, subtract the value of atomic absorption of a solution containing a standard solution, and the obtained values of atomic absorption and corresponding mass of gallium to build the calibration graph.

The value of atomic absorption solution in the reference experiment is subtracted from the value of atomic absorption of the sample solution and the calibration schedule find a lot of gallium in the sample solution.

3.4. Processing of the results

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

,

where is the mass of gallium in the sample solution found by the calibration schedule, mg;

 — the weight of the portion of the sample,

3.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.2.