GOST 3240.5-76

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  ГОСТ 3240.5-76

GOST 3240.5−76 magnesium Alloys. Methods for determination of zirconium (Change No. 1)

GOST 3240.5−76

Group B59

INTERSTATE STANDARD

MAGNESIUM ALLOYS

Methods for determination of zirconium

Magnesium alloys.
Methods for determination of zirconium

ISS 77.120.20
AXTU 1709

Date of introduction 1978−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of aviation industry of the USSR

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 28.12.76 N 2889

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)

6. EDITION with Change No. 1, approved in June 1987 (IUS 11−87)


This standard specifies the titrimetric method for the determination of zirconium (at a mass fraction of zirconium from 0.05 to 1.5%) and photometric method for the determination of zirconium (at a mass fraction of zirconium 0.00005 to 0.01%)

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 3240.0.

2. TITRIMETRIC METHOD FOR DETERMINATION OF ZIRCONIUM

2.1. The essence of the method

The method is based on dissolving the sample in hydrochloric acid and titration of zirconium with a solution of disodium salt of ethylenediaminetetraacetic acid.

2.2. Reagents and solutions

Hydrochloric acid according to GOST 3118, diluted 1:1 and 1:6, 2 M solution.

Hydroxylamine hydrochloric acid according to GOST 5456, 10% solution.

Sodium preservatory on the other 6−09−5404.

Selenology orange, 0,1% solution, prepared and stored according to GOST 4919.1.

Fenilalanina acid, 1% solution.

Zirconium (IV) oxychloride, 8-water (zirconyl chloride).

Standard solution of zirconium: 0,353 g zirconyl chloride dissolved in 2 M hydrochloric acid solution and pour the solution volume of the same acid to 100 cm.

1 cmof the solution contains 1 mg of zirconium.

To install the titer of a solution of zirconium pipetted 10 cmof the solution in a beaker with a capacity of 250 cm, add 20 cmof hydrochloric acid diluted 1:1, and 100 cmof water. The solution is heated to boiling, and add 15 cmphenylarsonic acid. The solution with the precipitated sediment was boiled for 10 min, avoiding violent boiling. Filtered through two medium density filter and washed 5−6 times with hot water. The filter residue is dried, burned and calcined at 1050 °C for 3 hours.

The titer of a solution of zirconium (), expressed in g/cmof zirconium, calculated by the formula

,

where is the mass of zirconium dioxide, g;

0, 703 — the ratio of zirconium dioxide to zirconium;

 — aliquota part of the chloride solution Zirconia, cm.

Salt is the disodium Ethylenediamine-N, N, N', N '-tetraoxane acid (Trilon B) according to GOST 10652, of 0.0125 M solution; prepared as follows: 4,6531 g Trilon B dissolved in 1000 cmof water. The titer of the solution Trilon B are placed on the zirconium chloride solution in the following way: 5 cmstandard solution of zirconium taken in a conical flask with a capacity of 250 cm, 70 cm pouredwater, heated to 80−90 °C, 30 cmof a solution of hydrochloric acid hydroxylamine and six drops of orange kylinalove. Titrated with a solution of Trilon B to change the color of the solution from pink to yellow.

The titer of the solution Trilon B (), expressed in g/cmof zirconium, calculated by the formula

,

where is the number of zirconium contained in aliquote parts of a solution of zirconium, g;

 — volume of solution Trilon B, spent on titration, sm.

2.3. Analysis

The weight of the portion of the alloy is determined depending on the content of zirconium, as indicated in the table.1.

Table 1

The sample of alloy is placed in a conical flask with a capacity of 250 cmand dissolved by heating in 30 cmof hydrochloric acid diluted 1:1.

To the hot solution was poured 70 cmof water heated to 80−90 °C, 30 cmof a solution of hydrochloric acid hydroxylamine, six drops of orange kylinalove and the hot solution titrated with a solution of Trilon B till color changes from pink to a steady yellow.

If upon dissolution of the alloy remains with the insoluble black precipitate of basic zirconium, it is filtered through the filter medium density, and precipitate was washed 6−8 times with hot hydrochloric acid solution, diluted 1:6. The filter with the residual burned, calcined for 30 min at 800 °C and fused at 500−600 °C with a fivefold amount peacemaking sodium. The smelt is dissolved in 100 cmwater and 10 cmof hydrochloric acid when heated. Combine the filtrate obtained after fusing the solution and determine the zirconium as indicated above.

2.1−2.3. (Changed edition, Rev. N 1).

2.4. Processing of the results

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

,

where  — volume of solution Trilon B, used for titration, cm;

the titer of the solution Trilon B, expressed in g/cmzirconium;

 — the weight of the portion of alloy,

2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.2.

Table 2

2.4.1; 2.4.2. (Changed edition, Rev. N 1).

2.5. Control of measurement accuracy

To control the accuracy of measuring the mass fraction of zirconium from 0.05 to 1.5% using the state standard samples, industry-standard samples and standard samples of the enterprise of magnesium alloys, issued in accordance with GOST 8.315. Accuracy control measurement is carried out in accordance with GOST 25086.

Allowed to control the accuracy of measuring the mass fraction of Zirconia, using addition method.

(Added, Rev. N 1).

3. PHOTOCOLORIMETRIC METHOD FOR DETERMINATION OF ZIRCONIUM

3.1. The essence of the method

The method is based on formation of colored compounds of zirconium, arsenazo III environment 9 M hydrochloric acid. Absorbance is proportional to the concentration of zirconium in the range of 0.5−5 g in 25 cmof a solution. The response sensitivity of 0.15 µg in 25 cm. The optical density measured at 670 nm. Interfere with the measurement of uranium and thorium.

3.2. Apparatus, reagents and solutions

The spectrophotometer SF-46, SF-26 or colorimeter KFK-2.

Hydrochloric acid according to GOST 3118, diluted 1:1, 0.2 M and 9 M solutions.

Sulfuric acid according to GOST 4204.

Fenilalanina acid, 0,1% solution.

Arsenazo, III, a 0.1% aqueous solution.

The zirconium metal or zirconium (IV) oxychloride, 8-water.

Potassium sulfate according to GOST 4145.

Ammonia water according to GOST 3760.

Standard solutions of zirconium.

Solution a with a concentration of 1 mg/cmis prepared from chloride Zirconia according to claim 2.2 or of the metal zirconium:

1 g of zirconium metal is placed in a beaker with a capacity of 200 cm, flow 50 cmsulphuric acid and add 10 g of potassium sulfate. Beaker cover watch glass and heated until the appearance of dense sulphuric acid fumes. After complete dissolution of the sample zirconium contents of the Cup diluted with water, heated to boiling and precipitated Zirconia by ammonia. Koagulirovat to give the residue, is filtered off, washed with water with a few drops of ammonia.

Then the filter cake is dissolved in hydrochloric acid, diluted 1:1, and again precipitated zirconium hydroxide with ammonia. Filtered off and washed as in the first case.

The filter cake was dissolved in 34 cmwith hot hydrochloric acid, diluted 1:1 in a glass, where he conducted the deposition. The filter is washed several times with hot water. The solution was then transferred to a volumetric flask with a capacity of 1 DM, after cooling, the solution is topped up to the mark with water and mix.

1 cmof the solution contains 1 mg of zirconium.

Solution B: prepare by diluting the solution And 20 times the 0.2 M solution of hydrochloric acid.

1 cmof solution B contains 5 µg of zirconium.

Solution: is prepared before use by dilution of a solution 10 times with 0.2 M hydrochloric acid solution.

1 cmof the solution contains 5 µg of zirconium.

The titer of the standard solution And installed in accordance with paragraph 2.

2.

3.3. Analysis

A sample of alloy weighing 1 g (at a mass fraction of zirconium of up to 0,0005%) and 0.1 g (with a mass fraction of zirconium, from 0.0005 to 0.2%) were placed in a glass with a capacity of 100−150 cmand dissolved in 15 cm9 M hydrochloric acid solution. After dissolution the solution was transferred to a volumetric flask with a capacity of 25 cm, is added to the flask 0.5 cmof the solution, arsenazo III and topped to the mark of 9 M hydrochloric acid solution.

When the mass fraction of zirconium in the alloy is 0.005 to 0.02% flask topped up to the mark without adding, arsenazo III 9 M hydrochloric acid solution, aliquot part of 5 cm,transferred to another flask with a capacity of 25 cm, add 0.5 cmof the solution, arsenazo III and topped to the mark with the same acid.

Measure the absorbance at a wavelength of 670 nm in a cuvette with the thickness of the absorbing layer of 3 cm relative to the water.

From the obtained values subtracted optical density of control solution. Mass fraction of zirconium calculated according to the calibration schedule

.

3.3.1. Construction of calibration curve

In glasses with a capacity of 100−150 cmenter 0; 0,1; 0,2; 0,4; 0,6 and 1,0 cmof solution, which corresponds to 0; 0,5; 1,0; 2,0; 3,0; 5,0 mcg Zirconia, add 15 cmto 9 M hydrochloric acid solution and boiled for 5−10 min to break down the polymers of zirconium. The solutions were transferred to volumetric flasks with a capacity of 25 cm, add 0.5 cmof the solution, arsenazo III and topped to the mark with the same acid. Measure the absorbance at 670 nm against water by subtracting the value of optical density of control solution. According to the obtained values build the calibration graph.

3.4. Processing of the results

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

,

where is the mass of zirconium was found in the calibration schedule, mcg;

 — the weight of the portion of alloy,

In the determination of 0.005−0.02% zirconium with the use of dilution, the result is multiplied by 5.

3.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.3.

Table 3

3.5. Control of measurement accuracy

3.5.1. Accuracy control measurement is carried out according to claim 2.5.

Sec. 3. (Changed edition, Rev. N 1).