GOST 11739.2-90

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  ГОСТ 11739.2-90

GOST 11739.2−90 Alloys aluminium cast and wrought. Methods of boron determination

GOST 11739.2−90

Group B59

STATE STANDARD OF THE USSR

ALLOYS ALUMINIUM CAST AND WROUGHT

Methods of boron determination

Aluminium casting and wrought alloys. Methods for determination of boron

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; 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 1961

3. The frequency of inspection — 5 years

4. Replace GOST 11739.2−78

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard establishes photometric methods for determination of boron with 1,1'-centrimide (when the mass fraction of boron from 0.001 to 0.5% and from 0.0001 to 0.001%).

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 BORON

2.1. The essence of the method

The method is based on dissolving the sample in a solution of sodium hydroxide, the formation of the blue complex of boron with 1,1'-dentriticum in concentrated sulfuric acid at a temperature of (100±2) °C and subsequent measurement of optical density at a wavelength of 630 nm.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Drying oven with thermostat.

Apparatus quartz distillation water.

Quartz test tubes with ground stoppers.

Water, double-distilled in quartz apparatus (redistilled for the preparation of solutions and analysis); stored in a plastic container.

Sodium hydroxide according to GOST 4328, a solution of 250 g/DM. The solution is prepared and stored in plastic container.

Sulfuric acid according to GOST 4204, density 1.84 g/cm, free from traces of nitric acid (sample acid in the presence of diphenylamine is not colored in blue) and a solution of 0.5 mol/DM.

Diphenylamine according to GOST 5825.

1,1'-dianthrone on the other 6−09−1508, a solution of 0.10 g of 1,1'-centrimide dissolved in 200 cmof sulphuric acid in a dry flask with a glass stopper. The flask previously dried in a drying Cabinet at a temperature of 100−110 °C With subsequent cooling.

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

The technical rectified ethyl alcohol according to GOST 18300.

Boric acid according to GOST 9656.

The standard solutions of boron.

Solution a: 0,5715 g of boric acid (H. h or the OS.h.) dissolved by heating in 500 cmof a solution of sulfuric acid, the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, made up with the same solution of sulfuric acid to the mark and mix.

1 cmof the solution contains 0.0001 g of boron.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, top up with sulphuric acid solution to the mark and mix.

1 cmof solution B has the 0.00001 g of boron.

Solutions stored in plastic pic

UD.

2.3. Preparation for assay

Before analysis, approximately 1 g chip samples washed two times with ethanol in portions of 25 cmand dried in a drying Cabinet at a temperature of (105+5) °C for 15−20 min.

2.4. Analysis

2.4.1. A portion of the sample mass according to table.1 is placed in a quartz conical flask with a capacity of 250 cmor a beaker made of PTFE with a capacity of 200 cm, pour the sodium hydroxide solution according to table.1, 10 cmof redistillate and dissolved under moderate heating.

Table 1

After complete dissolution of the sample into the flask add 10 cmof redistillate and carefully neutralize the solution with sulphuric acid according to table.1, adding it in small portions from a pipette along the walls of the flask.

The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, top up with redistillation to the mark and mix.

2.4.2. In a dry quartz tube with a glass stopper with a capacity of 50 cmis taken aliquot part of the solution according to the table.1, pour an eyedropper of 26−28 cmof sulphuric acid to a volume of 30 cmand 10 cmsolution of 1,1'-centrimide. Close the test-tube stopper and mix the solution, put it in a boiling water bath where it was heated for 1 h.

2.4.3. The optical density of the sample solution is measured after cooling to room temperature at a wavelength of 630 nm in a cuvette with a layer thickness of 50 mm at a mass fraction of boron from 0.001 to 0.01% and 20 mm with mass fraction of boron in excess of 0.01%.

Solution comparison is the solution of sulfuric acid.

2.4.4. Solutions control experiments are prepared according to PP.2.4.1, 2.4.2 all used in the analysis reagents. The average absorbance of the control experiments is subtracted from the optical density of the sample solution.

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

2.4.5. Construction of calibration graphs

2.4.5.1. When the mass fraction of boron from 0.001 to 0.01% in eight quartz conical flasks with a capacity of 250 cmis placed hitch aluminum weighing 0.5 g, dissolve according to claim 2.4.1 and in six flasks measure 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution B, which corresponds to 0,000005; 0,00001; 0,00002; 0,00003; 0,00004; 0,00005 g boron.

2.4.5.2. When the mass fraction of boron from 0.01 to 0.1% in eight quartz tubes placed hinge aluminum weighing 0.25 g, dissolve according to claim 2.4.1 and in six flasks measure 0,25; 0,5; 1,0; 1,5; 2,0; 2,5 cmstandard solution A, which corresponds to 0,000025; 0,00005; 0,0001; 0,00015; 0,0002; 0,00025 g boron.

2.4.5.3. When the mass fraction of boron from 0.1 to 0.5% in seven quartz conical flasks placed hinge aluminum weighing 0.1 g, dissolve according to claim 2.4.1 and five of the flasks measure 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution A, which corresponds to 0,0001; 0,0002; 0,0003; 0,0004; 0.0005 g of boron.

Then the solutions were transferred to volumetric flasks with a capacity of 100 cm, top up with redistillation to the mark, mix and continue at PP.2.4.2 and 2.4.3.

Solutions that are not entered Bor, are the solutions in the reference experiment when constructing the calibration graphs.

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

2.5. Processing of the results

2.5.1. Mass fraction of boron in percent is calculated by the formula

, (1)

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

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

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

Table 2

3. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF BORON WITH CHROMATOGRAPHIC SEPARATION

3.1. The essence of the method

The method is based on dissolving the sample in a mixture of sulfuric, nitric, hydrochloric acids, separation of boron and aluminum on the cation, the formation of the blue complex of boron with 1,1'-dentriticum in concentrated sulfuric acid at a temperature of (100±2) °C and measuring optical density at a wavelength of 630 nm.

3.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Drying oven with thermostat.

Apparatus quartz distillation water.

Quartz conical flask with a quartz air refrigerators.

Quartz chromatographic column.

The quartz glasses.

Quartz test tubes with ground stoppers.

Water, double-distilled in quartz apparatus (redistilled for the preparation of solutions and analysis); stored in a plastic container.

Sulfuric acid according to GOST 4204, density 1.84 g/cmand a solution of 0.5 mol/DM.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cmand a solution of 1:3, 1:1.

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

A mixture of acid: 2 parts of sulphuric acid, 3 parts hydrochloric acid, 4 parts of nitric acid, 7.5 parts of redistillate volume.

Ammonia water according to GOST 3760, density of 0.91 g/cm.

Hydrogen peroxide according to GOST 10929.

1,1' -dianthrone on the other 6−09−1508, the solution is prepared according to claim 2.2.

Aluminium GOST 11069 brand А999.

The technical rectified ethyl alcohol according to GOST 18300.

Cation exchange resin KU-2 according to GOST 20298.

Ammonium radamisty according to GOST 27067, a solution of 10 g/DM.

Paper universal indicator on the other 6−09−1181.

Boric acid according to GOST 9656.

The standard solutions of boron

Solutions a and B according to claim 2.2.

Solution: 10 cmof a solution transferred to a volumetric flask with a capacity of 100 cm, top up with sulphuric acid solution 0.5 mol/DMup to the mark and mix; prepare before use.

1 cmof the solution contains 0,000001 g b

ora.

3.3. Preparation for assay

3.3.1. Before analysis approximately 2 g of shavings samples washed 2 times with ethanol in portions of 30 cmand dried at a temperature of (105+5) °C in an oven for 15−20 min.

3.3.2. The cation exchanger KU-2 for translation in H-form is poured with hydrochloric acid and leave for a day. Then charged in a quartz chromatography column with a height of 30−40 cm, with a diameter of 2 cm (the height of the layer 25 cm) and washed with hydrochloric acid (1:1) until negative reaction to the ferric ion (sample deriving from the column of the solution with ammonium radamisty).

Upon reaching a negative response to iron ion (sample solution with ammonium radamisty not colored in red) cation exchange resin was washed with redistillation to neutral reactions resulting from the column solution (pH 7, sample by universal indicator paper).

3.3.3. For the regeneration of the cation exchanger KU-2 after separation of boron, aluminum and other elements through a chromatographic column is passed 300−350 cmof the hydrochloric acid solution (1:3) and 150−200 cmof redistillate to neutral reactions resulting from the column of the solution. The completeness of elution of aluminium and other elements from the cation exchange resin with hydrochloric acid, neutralization of the test portion of the solution flowing from the column, ammonia is the lack of turbidity of the solution.

3.4. Analysis

3.4.1. A portion of the sample weighing 1 g when the mass fraction of boron from 0.0001−0,0005% and 0.5 g for the mass concentration of boron from about 0.0006 to 0.001% placed in a quartz flask with a capacity of 250 cmfrom ground air refrigerator and dissolved in 10−20 cmof the mixture of acids at room temperature or at a very gentle heat.

3.4.2. Upon dissolution of the sample air cooler is washed with 10 cmof redistillate and dilute the solution to 30−40 cm. Silicic acid is filtered through the filter medium density («white ribbon»), inserted in a quartz or plastic funnel, washed precipitate of silicic acid 10−15 cmhot redistillate, adding it in small portions. Each the next portion is added after fully drained the previous. The filtered solution was diluted to a volume of 60 cmwith thedistillation and passed through a column of cation exchange resin KU-2 in N-form at a speed of 1 cm/min.

3.4.3. The solution from the column is collected in quartz glass with a capacity of 250 cm, add 10 cmsulphuric acid and 5 cmof hydrogen peroxide. The column is washed with 100−150 cmof redistillate at a speed of 10 cm/min and collect the washings in the same beaker. The solution in the beaker is evaporated until the appearance of white vapors. The side of the Cup is washed with 5−10 cmof redistillate from a pipette, and again evaporated to white fumes.

3.4.4. The solution from the beaker is transferred to a volumetric flask with a capacity of 25 cm, the glass is washed with a small amount of sulfuric acid and poured acid into the flask, dilute the solution in the flask with the same acid to the mark and transferred into a dry quartz tube with a glass stopper with a capacity of 50 cm. The flask is washed from the pipette 5 cmof sulphuric acid and poured acid into the basic solution. Add by pipette 10 cmof a solution of 1,1'-centrimide, close the test tube with a stopper, the solution was stirred and heated for 1 h in a boiling water bath.

3.4.5. Optical density of the solution is measured after cooling to room temperature at a wavelength of 630 nm in a cuvette with a layer thickness of 20 mm. Solution comparison is a solution of sulfuric acid.

3.4.6. The solutions of the two control experiments are prepared according to PP.3.4.1, 3.4.2, 3.4.3, 3.4.4 with 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 boron is calculated according to the calibration schedule.

3.4.7. For construction of calibration curve eight quartz glasses with a capacity of 250 cm10−15 cm pour themixture of acids and diluted to 60 cmwith redistillation. Then measure out six cups 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 cmstandard solution, which corresponds to 0,000001; 0,000002; 0,000004; 0,000006; 0,000008; 0,00001 g boron. To the resulting solution add 10 cmsulphuric acid and 5 cmof hydrogen peroxide. The solutions were evaporated until the appearance of white vapors, wash the walls of the Cup 5 cmof redistillate and again evaporated until the appearance of white vapors. Transfer the solutions from the beakers into a measuring flask with a capacity of up to 25 cmand come forth according to claim 3.4.4.

Solutions that are not entered Bor, are the solutions in the reference experiment when constructing the calibration graphs.

According to the obtained values of optical density of the solutions and their corresponding masses of the boron build the calibration.

K.

3.5. Processing of the results

3.5.1. Mass fraction of boron in percent is calculated by the formula

, (2)

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

 — the weight of the portion of the sample,

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