GOST 17051-82

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  ГОСТ 17051-82

GOST 17051−82 Steel alloyed and high alloy. Methods for determination of tantalum (with Amendments No. 1, 2)

GOST 17051−82

Group B39

STATE STANDARD OF THE USSR

STEEL ALLOYED AND HIGH-ALLOYED

Methods for determination of tantalum

Alloyed and high-alloyed steels.
Methods for determination of tantalum

AXTU 0809

Date of introduction 1983−01−01

INFORMATION DATA

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

DEVELOPERS

N. P. Liakishev, G. V. Kozina, N. With. Belousova, T. V. Titova

2. APPROVED AND put INTO EFFECT by decision of the USSR State Committee for standards from 23.09.82 No. 3731

3. REPLACE GOST 17051−71

4. The standard fully complies ST SEV 2882−81

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Limitation of actions taken on the Protocol, the Interstate Council for standardization, Metrology and certification (ICS 2−93)

7. REVISED (June 1997) with Amendments No. 1, 2, approved in may 1987-February 1993 (IUS 8−87, 11−12−93)


This standard specifies the extraction-photometric method for the determination of tantalum (in weight percentage tantalum, from 0.002 to 1.00%) and photometric method (at a mass fraction of tantalum from 0.10 to 1.00%).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 28473.

(Changed edition, Rev. No. 1, 2).

2. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF TANTALUM

2.1. The essence of the method

The method is based on extraction of colored green connection fluoride complex of tantalum (V) with malachite green with a mixture of hexane and 1,2-dichloroethane, and then measure the optical density of the extract at a wavelength of 635 nm.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Laboratory scales for General purpose according to GOST 24104 second class of accuracy with the greatest weighing limit of 200 g or any other scale with the same metrological characteristics.

Hydrofluoric acid according to GOST 10484.

Sulfuric acid according to GOST 4204, and diluted 1:1.

Hydrogen peroxide according to GOST 10929, 30% solution.

Ammonium oxalate according to GOST 5712, a solution of 40 g/DM.

Ammonium fluoride according to GOST 4518, solution 100 g/l, freshly prepared. Solution store in a plastic container.

Malachite green (tetramethyl di-diaminobenzanilide), a solution of 0.0015 g/cm, freshly prepared.

-Hexane.

The dichloromethane technical according to GOST 1942, top grade.

Extraction mixture: 2 volume parts of hexane is mixed with 1.5 volume parts of ethylene dichloride technical.

A piece of steel, the chemical composition of which is similar to the chemical composition of the sample, with a mass fraction of less than 0.0002% of tantalum.

Solution background: a sample of steel weighing 3,125 g is placed in a platinum Cup, is allowed to carry out the dissolving in a Cup of glassy carbon or PTFE beaker, and dissolved by heating in 25 cmof a solution of hydrofluoric acid, adding 10 cmof a solution of hydrogen peroxide to portions of approximately 0.5 cm. The solution was evaporated prior to the selection of salts, after cooling, cautiously add 25 cmof sulfuric acid and repeat the evaporation until the appearance of sulphuric acid fumes. After cooling the salt is washed into the beaker 25 cmof a solution of ammonium oxalate, adding it in small portions (using a PTFE Cup operation is omitted). The solution is heated to dissolve the salt, cooled, transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with a solution of ammonium oxalate and stirred.

Allowed the use of the solution background prepared with metallic iron and of standard solutions or the sample elements, the mass fraction of which in the sample more than 0.5%.

The tantalum metal or tantalum palixid.

Standard solutions of tantalum.

Solution a: 0,1000 g of tantalum metal or 0,1221 g perioxide tantalum is dissolved in the platinum Cup 20 cmof a solution of hydrofluoric acid while heating, adding about 10 cmof hydrogen peroxide solution in portions of 0.5 cm. To the solution add 10 cmsulphuric acid and heated until the appearance of sulphuric acid fumes. After cooling the salt is dissolved in 40 cmof a solution of ammonium oxalate and heat. The solution was transferred to volumetric flask with a capacity of 1 DM, added 40 cmof sulfuric acid solution, add solution of ammonium oxalate to the mark and mix; useable for up to one week.

1 cmof solution A contains 0.1 mg of tantalum.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with a solution of ammonium oxalate and stir; cook before eating.

1 cmof a solution contains 0.01 mg of tantalum.

(Modified redakts

ia, Rev. No. 1, 2).

2.3. Analysis

2.3.1. The weight of steel depending on the tantalum content in the steel is determined by the table. 1. The weight of steel placed in the platinum Cup, is allowed to carry out the dissolving in a Cup of glassy carbon or PTFE beaker, and dissolved in 10 cmof a solution of hydrofluoric acid while heating, adding 5−7 cmof a solution of hydrogen peroxide in portions of 0.5 cm.

Table 1

To the solution add 10 cmsulphuric acid and heated until the appearance of sulphuric acid fumes. After cooling, add about 25−30 cmof a solution of ammonium oxalate and dissolved salts at a moderate heat. Cool, transfer the solution into volumetric flask, washing the walls of the Cup or glass PTFE with a solution of ammonium oxalate. The capacity of the flask and the solution volume introduced into the flask of sulfuric acid is determined according to table. 1. Topped up to the mark with a solution of ammonium oxalate and stirred.

From the solution taken aliquot part by volume of 5 cmand placed in a polyethylene separatory funnel or plastic vessel. To the solution using the burette add 1 cmof sulfuric acid solution, 5 cmof a solution of ammonium fluoride, stirred and allowed to stand 3 min, then add 2cmof a solution of malachite green and stir. Directly after this, the solution is shaken with 5 cmof the extraction mixture for 1−1,5 min.

After phase separation, the extract taken with a plastic pipette or drained from the separating funnel in a glass beaker with a capacity of 50 cmand the cuvette with the thickness of the absorbing layer 10 mm. Cuvette, close lid and immediately measure the optical density of the extract at a wavelength of 635 nm. As a solution the comparison is used extract the zero solution (see table. 3).

(Changed edition, Rev. No. 1 2

).

2.3.2. To build a calibration curve of six flasks with a capacity for 50 cmflow depending on the mass fraction of tantalum volumes of background solution and sulfuric acid solution according to table. 2.

Table 2

Add to the flask the volume of a standard solution of tantalum Used in accordance with the table. 3.

Table 3

All volumetric flasks were topped up with a solution of ammonium oxalate to the mark and the contents mixed.
From solutions take aliquote part by volume of 5 cmand placed in a polyethylene separatory funnel or plastic vessel. Then do according to claim 2.3.1.

The optical density of the extracts is measured in relation to the extract of the zero solution. According to the obtained values of optical density of the extracts and their corresponding masses of the Tantal build the calibration graph.

(Changed edition, Rev. No. 2).

2.4. Processing of the results

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

,

where is the mass of tantalum in aliquote part of the analyzed solution found by the calibration schedule g;

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

2.4.2. Norms of accuracy and norms control the accuracy of determining the mass fraction of tantalum is shown in table. 4.

Table 4

(Changed edition, Rev. No. 2).

3. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF TANTALUM

3.1. The essence of the method

The method is based on the separation of tantalum from the rate of the solution with sulphurous acid, reprecipitation phenylarsonic the acid, the formation of yellow colored tantalum compounds with pyrogallol in the solution of phosphoric acid and measurement of optical density at a wavelength of 430 nm.

In the case of the presence of tungsten is further separation of tantalum deposition by magnesium sulphate in ammoniacal solution.

3.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Hydrochloric acid according to GOST 3118 and diluted 1:5 and 1:10.

Sulfuric acid according to GOST 4204, and diluted 1:1.

Nitric acid according to GOST 4461.

Orthophosphoric acid according to GOST 6552, diluted 1:3.

Perchloric acid, 57−60% solution.

Sulfurous acid, 6% solution.

Hydrofluoric acid according to GOST 10484.

Ammonia water according to GOST 3760.

Potassium preservatory according to GOST 7172.

Potassium carbonate technical GOST 10690.

Sodium carbonate according to GOST 83.

A mixture of anhydrous potassium carbonate and anhydrous sodium carbonate in a ratio of 3:1 and 1% solution.

Magnesium sulfate 7-water according to GOST 4523.

Ammonium chloride according to GOST 3773 and a solution of 250 g/DM.

Fenilalanina acid, a solution of 25 g/DM.

Wash solution 1: 100 cmphenylalaninol solution of acid is diluted with 100 cmof water.

Ammonium oxalate according to GOST 5712, a solution of 40 g/DM.

Pyrogallol, a solution of 0.4 g/cm, freshly prepared.

Precipitating solution 1:40 g of ammonium chloride dissolved in 400 cmof water. To the solution was added 40 cmof ammonia, is poured into a measuring flask with a capacity of 500 cm, made up to the mark with water and mix.

Precipitating a solution of 2: 40 g of magnesium sulfate dissolved in 400 cmof water. The solution was transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

Wash solution 2: 200 cmprecipitating solution 1 dissolve 2 g potassium carbonate. To the solution are added 200 cmprecipitating solution 2, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

Solution peacemaking of potassium and of ammonium oxalate: 14 g potassium peacemaking placed in a platinum Cup and heated in a muffle furnace prior to melting. After cooling to afloat add 5 drops of sulfuric acid. The melt is heated again to melt together. After cooling, the melt is dissolved in a beaker with a capacity of 250 cmin 100 cmof solution of ammonium oxalate at the moderate heating and constant stirring. The solution was transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with a solution of ammonium oxalate and stirred.

The tantalum palixid.

Standard solution tantalum: 0,1526 g perioxide tantalum was placed in a platinum Cup and heated in a muffle furnace prior to melting with 14 g of potassium peacemaking. Then do according to claim 2.2; usable for up to one week.

1 cmof the solution contains 0.25 mg of tantalum.

(Amended

, Edit. No. 1).

3.3. Analysis

3.3.1. The weight of the portion of the sample depending on the mass fraction of tantalum in steel is determined by the table. 5. Weighed samples were placed in a glass with a capacity of 800 cm, flow 50 cmof hydrochloric acid and 15 cmof nitric acid and dissolved by heating. To the solution was added a solution of perchloric acid according to table. 5, is evaporated until the appearance of dense fumes of perchloric acid in a closed glass heating was continued for 10 min.

Table 5

After cooling the salt is dissolved in 200 cmof water. To the solution was added to 50 cmof a solution of sulphurous acid, is heated, boiled for 10 min and incubated for 30 minutes at a temperature of from 70 to 80 °C. the Solution was filtered using two filters with an average density of filtrowanie ground. Filter the precipitate first washed six times with hydrochloric acid (1:10) and then three times with hot water. The filter with the precipitate is transferred into a platinum Cup, the filter is incinerated and the residue is calcined at a temperature of 1000 °C. the Precipitate is moistened with 0.5 cmof sulfuric acid solution, add 5 cmof a solution of hydrofluoric acid, evaporated to dryness and fused with 5 g of a mixture of potassium carbonate-sodium.

After cooling, the melt is dissolved in a beaker with a capacity of 400 cmin water, the volume of which is chosen so as to intended for the deposition of the solution volume was 150−200 cm. The solution was filtered through a filter of medium density.

The filter with the sediment was washed five times with a solution of a mixture of carbonate of potassium, sodium, and cast. To the filtrate (filtrate A) was added to a solution of hydrochloric acid (1:5) to acidic reaction and after heating to a temperature of about 80 °C is added 30 cmof a solution of phenylarsonic acid. After 10 min the solution was filtered through a filter of medium density. The filter with the sediment was washed five times, using each time 10 cm1 wash solution and placed in a quartz crucible. The filter is carefully incinerated, and the residue was calcined at 1000 °C. Residue with 7 g of potassium peacemaking heated prior to melting. After cooling to going add five drops of sulfuric acid. The melt is heated again to melt together. After cooling, the melt is dissolved in a beaker with a capacity of 250 cmto 50 cmof a solution of ammonium oxalate at the moderate heating and constant stirring. The solution was transferred to volumetric flask with a capacity of 250 cm, adding 25 cmof a solution of phosphoric acid, add solution of ammonium oxalate to the mark and mix. Part of the solution filtered.

10 cmof the filtrate was poured into a glass and add 3 cmof a solution of pyrogallol. Not more than 5 min measure the optical density at a wavelength of 430 nm.

Solution comparison is the solution of the reference experiment.

(Redrafted From

M. No. 2).

3.3.2. In the case of the presence of tungsten in the filtrate And heated to a temperature of about 50 °C and added with stirring 25 cmprecipitating solution of 1 and then 25 cmof precipitating solution, 2. The solution for 60 min maintained at 50 °C and then filtered through a filter of medium density. The filter with the precipitate three times washed with flushing solution 2, then placed in a beaker with a capacity of 400 cm, with 30 cmof a solution of ammonium chloride. With a glass rod to destroy the filter with the sediment. The first solution was added a solution of hydrochloric acid (1:5) to acidic reaction and after heating to a temperature of about 80 °C is added 30 cmof a solution of phenylarsonic acid. Then do according to claim 3.3.1.

3.3.3. For construction of calibration curve six volumetric flasks with a capacity of 100 cmis poured under the table. 6 a standard solution of tantalum and added to 50 cmsolution peacemaking of potassium and of ammonium oxalate.

Table 6

To the solution is added to 10 cmof a solution of orthophosphoric acid, made up to the mark with a solution of ammonium oxalate and stirred.

From each solution taken in separate beakers of dry volume by 10 cmand add 3 cmof a solution of pyrogallol. Not more than 5 min measure the optical density at a wavelength of 430 nm. Solution comparison is the zero solution.

According to the obtained values of optical densities and their corresponding masses of the Tantal build the calibration graph.

(Changed edition, Rev. No. 2).

3.4. Processing of the results

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

,

where is the mass of tantalum in aliquote part of the analyzed solution found by the calibration schedule g;

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

3.4.2. Norms of accuracy and norms control the accuracy of determining the mass fraction of tantalum is shown in table. 4.

(Changed edition, Rev. No. 2).