GOST 19863.2-91

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  ГОСТ 19863.2-91

GOST 19863.2−91 Alloy of titanium. Methods for determination of vanadium

GOST 19863.2−91

Group B59

STATE STANDARD OF THE USSR

ALLOYS OF TITANIUM

Methods for determination of vanadium

Titanium alloys.
Methods for the determination of vanadium

AXTU 1709

Date of introduction 1992−07−01

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; M. N. Gorlova, PhD. chem. Sciences; A. I. Korolev, O. L. Sikorska, PhD. chem. Sciences

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 05.05.91 N 625

3. REPLACE GOST 19863.2−80

4. The frequency of inspection — 5 years

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard establishes titrimetric (mass fraction with from 0.1 to 6.0%) and atomic absorption (at a mass fraction of from 0.1 to 6.0%) 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. TITRIMETRIC 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 sulfuric and bridgestation acids, the oxidation of vanadium to pentavalent with potassium permanganate and titration it with a solution of double sulphate salts of protoxide of iron and ammonium (salt Mora) with phenylanthranilic acid as indicator.

2.2. Apparatus, reagents and solutions

Drying oven with thermostat.

Sulfuric acid according to GOST 4204 density 1.84 g/cm, mortar 1:1 and 1:5.

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

Hydrofluoric acid according to GOST 10484.

Boric acid according to GOST 9656.

Acid bridgestation: 280 cmhydrofluoric acid at a temperature of (10±2) °C add portions 130 g of boric acid and stirred. The reagent is prepared and stored in a plastic container.

Oxalic acid according to GOST 22180, a solution of 10 g/DM.

Potassium permanganate according to GOST 20490, solution 0,1 mol/DM.

Sodium carbonate according to GOST 83.

Acid N-phenylanthranilic on the other 6−09−3501, a solution of 2 g/DM: 0.2 g of sodium carbonate were placed in a glass with a capacity of 100 cm, was dissolved with heating in 50 cmof water, add 0.2 g phenylanthranilic acid, stirred and cooled to room temperature and add water to 100 cm.

Potassium dichromate according to GOST 4220, solutions of 0.1 and 0.02 mol/DM: 29,42 or 5.88 g of recrystallized potassium dichromate is placed in a measuring flask with volume capacity of 1000 cm, dissolved in 500 cmof water, made up to the mark with water and mix.

For recrystallization 100 g of potassium dichromate were placed in a glass with a capacity of 400 cm, 150 cm pour thewater and dissolved by heating. The solution with vigorous stirring pour in a thin stream in a porcelain Cup, which is cooled with ice water. Precipitated crystals filtered off with suction on a funnel with a porous glass plate, dried for 2−3 hours at temperature (102±2) °C, crushed, and finally dried at a temperature of (200±5) °C for 10−12 h

Salt of protoxide of iron and ammonium double sulfate (salt Mora) according to GOST 4208, solutions of 0.1 and 0.02 mol/DM: 39,5 or 7.9 g of salt Mora is placed in a beaker with a capacity of 800 cmand dissolved in 500 cmof water, poured 100 cmof sulfuric acid solution 1:1, cooled to room temperature, transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

Mass concentration solution of salt Mora (practical), expressed in g/cmvanadium (), calculated by the formula

, (1)

where 0,005095 mass concentration of salt solution Mora (theoretical), expressed in g/cmvanadium;

 — the relationship between solutions of potassium dichromate and salt Mora.

Set the ratio between the solutions of potassium dichromate and salt Mora: three conical flasks with a capacity of 250 cmshift 10 cmof a solution of potassium dichromate 0.1 or 0,02 mol/land diluted to 100 cmwith water, poured 20 cmof sulfuric acid solution 1:5, mix, add 5−6 drops phenylanthranilic acid and titrate with the appropriate solution of salt Mora until the color of solution from blue-violet to green.

Ratio , (2)

where is the volume of potassium dichromate solution used for titration, cm;

 — the volume of salt solution Mora, used for titration, sm.

The mass concentration of salt solution Mora set before use.

2.3. Analysis

2.3.1. A portion of the sample weight in accordance with table.1 is placed in a conical flask with a capacity of 250 cm, flow 60 cmof sulfuric acid solution 1:5, 2 cmbridgestation acid and heated until complete dissolution.

Table 1

The solution was added dropwise a solution of nitric acid until the disappearance of violet colour, 2−3 drops in excess, and evaporated to the appearance of sulphuric acid fumes. The solution was cooled to room temperature, poured 100 cmof water and dropwise a solution of potassium permanganate until a stable pink color. Then slowly dropwise added a solution of oxalic acid before bleaching.

The solution is titrated with a solution of salt Mora and 0.02 mol/DMfor the mass concentration of vanadium less than 0.5% or a solution of 0.1 mol/DMwhen the mass fraction of vanadium of more than 0.5% with 5−6 drops of indicator phenylantranilic acid until the solution colour from blue-violet to green.

2.4. Processing of the results

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

, (3)

where is the established mass concentration of salt solution Mora, expressed in g/cmvanadium;

 — the volume of salt solution Mora, used for titration of vanadium, cm;

 — weight of sample, g.

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 sample in hydrochloric and bridgestation acids and measurement of 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, mortar is 2:1 and 1:1.

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

Boric acid according to GOST 9656.

Hydrofluoric acid according to GOST 10484.

Acid bridgestation: 280 cmhydrofluoric acid at a temperature of (10±2) °C add portions 130 g of boric acid and stirred. The reagent is prepared and stored in a plastic container.

Titanium sponge according to GOST 17746* stamps TG-100.
_______________
* On the territory of the Russian Federation GOST 17746−96. — Note the manufacturer’s database.

Solutions titanium

Solution A, 20 g/DM: 4 grams of titanium sponge was placed in a conical flask with a capacity of 250 cm, 160 cm add asolution of hydrochloric acid 2:1, 8 cmbridgestation acid and dissolved with moderate heating. After dissolution of the sample add 2 cmof nitric acid and boil the solution for 1 min. the Solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 200 cm, made up to the mark with water and mix.

Solution B, 10 g/l: 1 g of titanium sponge is placed in a conical flask with a capacity of 250 cm, add 80 cmof a hydrochloric acid solution of 2:1, 4 cmbridgestation acid and dissolved with moderate heating. After dissolution of the sample add sixteen drops of nitric acid and boil the solution for 1 min. 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.

Ammonium undeviatingly meta GOST 9336.

A standard solution of vanadium: 2,2962 g vadeevaloo ammonium is placed in a conical flask with a capacity of 250 cm, add 50 cmof water 100 cmof hydrochloric acid of 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 cmstandard solution contains 0,0

01 g of vanadium.

3.3. Analysis

3.3.1. A portion of the sample mass according to table.3 is placed in a conical flask with a capacity of 100 cm, flow 20 cmof a hydrochloric acid solution of 2:1, 1 cmbridgestation acid and dissolved with moderate heating. After dissolving the sample, add ten drops of nitric acid and boil the solution for 1 min. the Solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 100 cm, add 2 cmof hydrochloric acid of 1:1, 10 cmbridgestation acid, 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.

3.3.3. Construction of calibration curve

3.3.3.1. When the mass fraction of vanadium from 0.1 to 0.5%

In six volumetric flasks with a capacity of 100 cmis placed 25 cmof a solution of titanium And, in five of them measure 0,5; 1,0; 1,5; 2,0; 2,5 cmstandard solution, which corresponds to 0,0005; 0,001; 0,0015; 0,002; 0.0025 g of vanadium.

3.3.3.2. When the mass fraction of vanadium from 0.5 to 2.0%.

Five volumetric flasks with a capacity of 100 cmis placed 25 cmof a solution of titanium And four of them measure 2,5; 5,0; 7,5; 10,0 cmstandard solution, which corresponds to RUB 0.0025; to 0.005; 0,0075; 0.01 grams of vanadium.

3.3.3.3. When the mass fraction of vanadium of more than 2.0 to 6.0%.

Five volumetric flasks with a capacity of 100 cmplaced at 20 cmof a solution of titanium Used, four of them measure 3,0; 6,0; 9,0; 12,0 cmstandard solution, which corresponds to 0,003; 0,006; 0,009; 0.012 g of vanadium.

3.3.3.4. The solutions in the flasks prepared according to claim.3.3.3.1, 3.3.3.2, 3.3.3.3, add 5 cmof hydrochloric acid 1:1, 10 cmbridgestation acid, made 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 (recovery) 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 a calibration curve in the coordinates «Value of atomic absorption — Mass concentration of vanadium, g/cm».

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

, (4)

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. The divergence of results should not exceed the values given in table.4.

Table 4