GOST 11739.26-90

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  ГОСТ 11739.26-90

GOST 11739.26−90 Alloys aluminium cast and wrought. Methods for the determination of gallium

GOST 11739.26−90

Group B59

STATE STANDARD OF THE USSR

ALLOYS ALUMINIUM CAST AND WROUGHT

Methods for the determination of gallium

Aluminium casting and wrought alloys.
Methods for determination of gallium

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; V. I. Klitina, PhD. chem. Sciences; M. N. Gorlova, PhD. chem. Sciences; O. L. Sikorska, PhD. chem. Sciences; L. N. Viksne

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 28.06.90 N 1963

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 gallium from 0.001 to 0.1%) and atomic absorption (at a mass fraction of gallium from 0.05 to 1.0%) methods for determination of gallium.

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 GALLIUM

2.1. The essence of the method

The method is based on dissolving the samples in hydrochloric acid with addition of nitric acid, butyl acetate extraction of gallium from hydrochloric acid solution, re-extraction with water, the formation of a pink complex of gallium with rhodamine C, extraction of the complex with a mixture of benzene with butyl acetate and measuring the optical density of the extract at a wavelength of 564 nm.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

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.

Titanium trichloride on the other 6−09−01−756.

Sodium chloride according to GOST 4233.

Rhodamine C, a solution of aqueous 5 g/DM.

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

Butyl ether of acetic acid on the other 6−09−781 (butyl acetate) compulsory distillation and the use of fractions with a boiling point (125±1) °C.

Benzene according to GOST 5955.

A mixture of butyl acetate and benzene 1:4 by volume.

Gallium metal according to GOST 12797.

Standard solutions of gallium.

Solution a: 0.25 g of gallium is dissolved by heating in 30 cmof a hydrochloric acid solution, the solution was transferred into a measuring flask with volume capacity of 1000 cmand topped to the mark with the same hydrochloric acid solution.

1 cmof solution A contains 0.00025 g of gallium.

Solution B: 10 cmsolution And transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with hydrochloric acid and stirred.

1 cmof solution B contains 0,0000025 g gall

ia.

2.3. Analysis

2.3.1. A portion of sample weighing 0.25 g was placed in a conical flask with a capacity of 100 cm, 20−30 cm pouredhydrochloric acid solution and dissolved by heating. If the sample contains copper, then add drop by drop nitric acid until complete dissolution of the sample. The solution was evaporated to wet salts. If you add nitric acid in a flask pour 10 cmof hydrochloric acid and again evaporate the solution to dryness. This operation is repeated twice. Dissolve the salt in 10 cmof hydrochloric acid and transferred the solution into a measuring flask with a capacity of 25 cm; the flask in which dissolution is carried out, wash with 5−10 cmof the same hydrochloric acid solution and poured it into the same volumetric flask. Added to the sample solution 1−1,5 cmtitanium trichloride until a stable violet colour and add hydrochloric acid to the mark. The solution from the flask transferred to a separatory funnel with a capacity of 100−150 cm, flask rinsed from the pipette 10 cmof the same hydrochloric acid solution and poured it into dividing Raven

ku.

2.3.2. To the solution in separating funnel add by pipette or from a burette 35 cmbutyl acetate, and shake the solution for 1 min to Separate the aqueous phase and washed twice with the organic phase (extract) 5 cmof hydrochloric acid solution by shaking the extract with an acid solution for 1 min.

2.3.3. To the extract was added 15 cmof water and shaken for 1 min. the Aqueous phase (reextract) poured in a porcelain Cup with a capacity of 50 cmand repeat the Stripping. The second aqueous phase is poured into the same porcelain Cup, add 0.1 g of dry sodium chloride and evaporated reextract in a water bath to dryness. The contents of the Cup is dissolved in 10 cmof hydrochloric acid and transferred the solution into a measuring flask with a capacity of 25 cm. Top up the solution with the same solution of hydrochloric acid to the mark and mix.

2.3.4. In a test-tube with stopper with a capacity of 25−30 cmis taken aliquot part of the solution according to the table.1, if necessary, refill the pipette to 5 cmof the hydrochloric acid solution is poured 0.2 cmtrichloride titanium, 10 cmof a mixture of butyl acetate and benzene and 0.5 cmof a solution of rhodamine C. the contents of the tube Shaken for 2 min. Separated the organic phase (extract) in the separating funnel and filtered it through a small paper filter «white ribbon» in a cuvette for optical density measurement.

Table 1

2.3.5. The optical density of the extract samples measured immediately after extraction at a wavelength of 564 nm in a cuvette with a layer thickness of 10 mm Solution comparison is a mixture of butyl acetate and benzene.

2.3.6. The solution in the reference experiment is prepared according to claim 2.3.1 all used in the analysis reagents. The average optical density of the solutions of the two control experiments is subtracted from the optical density of the sample solution. Mass fraction of gallium is calculated according to the calibration schedule.

2.3.7. Construction of calibration curve

In nine conical flasks with a capacity of 100 cmis placed hitch aluminum weighing 0.25 g, dissolve according to claim 2.3.1 in the seven flasks measure 1,0; 2,0; 4,0; 6,0; 8,0; 10,0; 12,0 cmstandard solution B, which corresponds to 0,0000025; 0,000005; 0,00001; 0,000015; 0,00002; 0,000025; 0,00003 g of gallium. Then the solutions were evaporated, dissolved salts in hydrochloric acid solution, extracted gallium butyl acetate according to claim 2.3.2, extravert gallium water according to claim 2.3.3, the extracted complex of gallium with rhodamine With claim 2.3.4 and measure the optical density of the extract according to claim 2.3.5.

As reference solutions, use solutions that do not contain gallium.

According to the obtained values of optical density of the extracts 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

, (1)

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

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

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

Table 2

3. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF GALLIUM

3.1. The essence of the method

The method is based on dissolving the samples in hydrochloric acid in the presence of hydrogen peroxide, and then measure the atomic absorbance of gallium at a wavelength of 287,4 nm in a flame acetylene-nitrous oxide.

3.2. Apparatus, reagents and solutions

Spectrophotometer of atomic absorption with a radiation source for gallium.

Acetylene according to GOST 5457.

Nitrous oxide medical.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cm, the solutions of 1:1, 1:99.

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

A mixture of hydrochloric and nitric acids in the ratio 3:1.

Sulfuric acid according to GOST 4204, density 1.84 g/cm.

Hydrofluoric acid according to GOST 10484.

Hydrogen peroxide according to GOST 10929.

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

Nickel chloride according to GOST 4038, a solution of 1 g/DM.

Aluminium GOST 11069 brand А999.

A solution of aluminum 20 g/DM: 10 g of aluminum is placed in a beaker with capacity of 500 cm, add 50 cmof water and then small portions of 300 cmof a hydrochloric acid solution (1:1) and dissolve with a moderate heat, adding 1 cmof solution of chloride Nickel. The solution was cooled to room temperature, 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.

Standard solutions of gallium

Solution a: 1 g of gallium metal is placed in a conical flask with a capacity of 250 cmadd 30 cmof a mixture of hydrochloric and nitric acids and dissolve with a moderate heat. The solution was cooled to room temperature, transferred into a measuring flask with volume capacity of 1000 cm, add 100 cmof hydrochloric acid (1:1), made up to the mark with water and mix.

1 cmof the solution contains 0.001 g of gallium.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, flow 10 cmof hydrochloric acid (1:1), made up to the mark with water and mix.

1 cmof solution B contains 0,

0001 g of gallium.

3.3. Analysis

3.3.1. A portion of sample weighing 0.5 g is placed in a conical flask with a capacity of 250 cm, pour approximately 10 cmof water and then small portions of 25 cmof a solution of hydrochloric acid (1:1). The beaker cover watch glass and heated until complete dissolution of the sample. Add 3−5 drops of hydrogen peroxide and boil the solution for 3 min.

Watch glass and walls of the flask rinsed with water. The solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 100 cm, add 10 cmof hydrochloric acid (1:1), 10 cmof ammonium chloride, made up to the mark with water and mix.

3.3.2. When the mass fraction of silicon is less than 1% solution, if it is not transparent, was filtered through a dry filter medium density (white ribbon) in a beaker, discarding the first portions of the filtrate.

3.3.3. When the mass fraction of silicon in excess of 1% after completion of dissolution according to claim 3.3.1 solution is filtered through a filter medium density (white ribbon) in a volumetric flask with a capacity of 100 cm. The filter cake was washed 2−3 times with hot hydrochloric acid (1:99) in portions of 10 cm(primary filtrate).

The filter with precipitate was placed in a platinum crucible, dried, incinerated, preventing ignition, and calcined at 500−600 °C for 3 min. After cooling the content of crucible add four drops of sulphuric acid, 5 cmhydrofluoric acid and nitric acid drop by drop until a clear solution. The solution was then evaporated to dryness and after cooling, the residue moistened with 2−3 cmof water and dissolve in 2−3 cmof hydrochloric acid of 1:1 under heating.

The solution is attached to the main filtrate in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

3.3.4. The solution in the reference experiment is prepared according to PP.3.3.1, 3.3.2, 3.3.3, using is sample the sample the sample of aluminium.

3.3.5. Construction of calibration graphs

3.3.5.1. When the mass fraction of gallium from 0.05 to 0.1% in seven volumetric flasks with a capacity of 100 cmpoured in 25 cmof a solution of aluminum in six of them measure 2,5; 3,0; 3,5; 4,0; 4,5; 5,0 cmstandard solution B, which corresponds to 0,00025; 0,0003; 0,00035; 0,0004; 0,00045; 0,0005 g of gallium.

3.3.5.2. When the mass fraction of gallium of from 0.1 to 1.0% in seven volumetric flasks with a capacity of 100 cmpoured in 25 cmof a solution of aluminum in six of them measure 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution A, which corresponds to 0,0005; 0,001; 0,002; 0,003; 0,004; 0,005 g of gallium.

3.3.5.3. The solutions in flasks (PP.3.3.5.1, 3.3.5.2) add 10 cmof hydrochloric acid (1:1), 10 cmof a solution of ammonium chloride, made up to the mark with water and mix.

3.3.6. 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 atomic absorbance of gallium at a wavelength of 287,4 nm.

According to the obtained values of atomic absorption and corresponding mass concentrations of gallium to build the calibration graph.

The mass concentration of gallium 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 (gallium) in percent is calculated by the formula

, (2)

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

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

 — the volume of the sample solution, cm;

 — weight of sample, g

.

3.4.2. Discrepancies in the results must not exceed the values given in table.3.

Table 3