GOST 11739.5-90

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  ГОСТ 11739.5-90

GOST 11739.5−90 Alloys aluminium cast and wrought. Methods for determination of vanadium

GOST 11739.5−90

Group B59

STATE STANDARD OF THE USSR

ALLOYS ALUMINIUM CAST AND WROUGHT

Methods for determination of vanadium

Aluminium casting and wrought alloys. Methods for determination of vanadium

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 1261

3. The frequency of inspection — 5 years

4. REPLACE GOST 11739.5−78

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies the photometric (with a mass fraction of from 0.005 to 0.5%) and atomic absorption (at a mass fraction of from 0.05 to 0.5%) methods for determination of vanadium.

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 VANADIUM

2.1. The essence of the method

The method is based on dissolving the sample in a mixture of hydrochloric and nitric acids, the oxidation of vanadium to pentavalent with potassium permanganate, the formation of yellow phosphorus-tungsten-vanadium heteroalicyclic, its extraction of isobutyl alcohol and measuring the optical density of the extract at a wavelength of 400 nm.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cm.

Nitric acid according to GOST 4461, density 1,35−1,40 g/cmand a solution of 1:7,5.

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

Hydrofluoric acid according to GOST 10484.

Sulfuric acid according to GOST 4204, density 1.84 g/cmand a solution of 1:3.

Orthophosphoric acid according to GOST 6552, a density of 1.70 g/cm.

Potassium permanganate according to GOST 20490, solution 0,01 mol/DM.

Oxalic acid according to GOST 22180, a solution of 40 g/DM.

Sodium volframovich according to GOST 18289, a solution of 50 g/DM: volframovich 50 g of sodium was dissolved with heating in 150 cmof water, the solution was filtered into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

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

Isobutyl alcohol according to GOST 6016.

Ammonium undeviatingly meta GOST 9336.

A standard solution of vanadium: 0,2296 g vadeevaloo ammonium are dissolved in 170 cmnitric acid. The solution is transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g VA

Nadia.

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 250 cm, 40 cm, pour themixture of acids and dissolved by heating.

Table 1

Upon completion of the dissolution poured into the flask 20 cmof sulfuric acid, stirred and evaporated the solution until the appearance of white vapors. The solution was cooled, poured 60−80 cmof water and heated to dissolve the salts. If the solution is not transparent, it is filtered through the filter medium density (white ribbon) in a conical flask with a capacity of 250 cm. Filter the precipitate was washed 2−3 times with small portions of hot water and drop, if the mass fraction of silicon in the analyzed alloy does not exceed 1%.

2.3.2. When the mass fraction of silicon in excess of 1% of the filter with the sediment was placed in a platinum crucible, dried, incinerated, preventing ignition, and calcined at 500−600 °C for 2−3 min. After cooling in the crucible add four drops of sulphuric acid, 5 cmhydrofluoric acid and nitric acid drop by drop until a clear solution. The solution was evaporated to dryness, poured to the dry residue in the crucible 5−7 cmof sulfuric acid solution and dissolved under heating. The solution was then cooled, if necessary, filtered through a small, dense filter («blue ribbon») and added to the main filtrate in the conical flask. The main solution is evaporated, if necessary, to a volume less than 100 cm, cooled and transferred to volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

2.3.3. Aliquot part of the solution according to the table.1 taken in a separating funnel with a capacity of 100 cm, pour 4 cmof phosphoric acid, 4 cmsolution volframovich sodium and stirred. Then added dropwise a solution of potassium permanganate until a stable pink color. After 10 minutes, add dropwise a solution of oxalic acid until the disappearance of the pink color. After 5 minutes pour 1 cmof nitric acid, a well-stirred solution, add 10 cmisobutyl alcohol, a funnel closed with a stopper and shake for 1−2 min to Separate the organic phase (extract), collecting it in a dry volumetric flask with a capacity of 25 cm, add isobutyl alcohol to the mark and mix.

2.3.4 the Optical density of the extract is measured not later than 1 h after extraction at a wavelength of 400 nm in a cuvette with a layer thickness of 50 mm at a mass fraction of vanadium from 0.005 to 0.1% and 30 mm for the mass concentration of vanadium than 0.1%. Solution comparison is isobutyl alcohol.

2.3.5. The solutions in the reference experiment is prepared according to claim 2.3.1, using is sample the sample the sample of aluminium. The average optical density of the extracts of two control experiments is subtracted from the optical density of the extract samples.

Mass fraction of vanadium is calculated according to the calibration schedule.

2.3.6. Construction of calibration graphs

2.3.6.1. When the mass fraction of vanadium from 0.005 to 0.05% in six conical flasks with a capacity of 250 cmis placed a sample of aluminium of mass 1 g and dissolved in 40 cmof a mixture of acids. Then the four flasks measure 0,5; 1,0; 3,0; 5,0 cmstandard solution of vanadium, which corresponds to 0,00005; 0,0001; 0,0003; 0,0005 g of vanadium.

2.3.6.2. When the mass fraction of vanadium of 0.05 to 0.1% in seven conical flasks with a capacity of 250 cmis placed hitch aluminum weighing 0.5 g and after dissolving at 40 cmof the mixture of acids in five of them measure 2,5; 3,5; 4,0; 4,5; 5,0 cmstandard solution of vanadium, which corresponds to 0,00025; 0,00035 full; 0,0004; is 0 00 045; 0.0005 g of vanadium.

2.3.6.3. When the mass fraction of vanadium from 0.1 to 0.5% in seven conical flasks with a capacity of 250 cmplace of mounting the aluminium weight of 0.2 g and after dissolving at 40 cmof the mixture of acids in five of them poured 2,0; 4,0; 6,0; 8,0; 10,0 cmstandard solution of vanadium, which corresponds to 0,0002; 0,0004; about 0.0006; 0.0008 inch; 0.001 g of vanadium.

2.3.6.4. In the flask poured with 20 cmof sulphuric acid and continue at PP.2.3.1, 2.3.2 and 2.3.3.

Solutions that do not contain vanadium, are the solutions in the reference experiment when constructing the calibration graphs.

According to the obtained values of optical density of the extracts and their corresponding masses of vanadium build calibration graphs.

2.4. Processing of the results

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

, (1)

where is the mass of vanadium 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. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF VANADIUM

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 subsequent measurement of the atomic absorption of vanadium at a wavelength of 318,5 nm in a flame acetylene-nitrous oxide.

3.2. Apparatus, reagents and solutions

Spectrophotometer of atomic absorption with a radiation source for vanadium.

Acetylene according to GOST 5457.

Nitrous oxide medical.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cm, a solution of 1:1 and 1:99.

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

Sulfuric acid according to GOST 4204, density 1.84 g/cm, a solution of 1:1.

Hydrofluoric acid according to GOST 10484.

Hydrogen peroxide according to GOST 10929.

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, 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.

Ammonium undeviatingly meta GOST 9336.

Standard solutions of vanadium.

Solution a: 2,2963 g vadeevaloo ammonium is placed in a conical flask with a capacity of 250 cm, flow 50 cmof water 100 cmof hydrochloric acid (1:1) and dissolved under moderate heating. The solution was cooled to room temperature, 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 0.001 g of vanadium.

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 0,00

01 g of vanadium.

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, heat to completely dissolve 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, 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 3−4 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 contents of the crucible add 4 drops of sulfuric acid, 5 cmhydrofluoric acid and nitric acid drop by drop until a clear solution. The solution was then evaporated to dryness, after cooling, the residue moistened with 2−3 cmof water and dissolve in 2−3 cmof hydrochloric acid (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 control experience is prepared according to PP.3.3.1, 3.3.2 or 3.3.3, using is sample the sample the sample of aluminium.

3.3.5. Construction of calibration curve

In seven volumetric flasks with a capacity of 100 cmpoured in 25 cmof a solution of aluminium in three of them measure 2,5; 5,0; 10,0 cmstandard solution B, the following three measure 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 of vanadium. The solutions in volumetric flasks topped 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 absorption of vanadium at a wavelength of 318,5 nm.

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

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

, (2)

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

 — mass concentration of vanadium 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