GOST 1953.8-79

• gost-19538-79.pdf (600.65 KiB)
  ГОСТ 1953.8-79

GOST 1953.8−79 Bronze tin. Methods for determination of aluminium (with Amendments No. 1, 2)

GOST 1953.8−79

Group B59

INTERSTATE STANDARD

BRONZE TIN

Methods for determination of aluminium

Tin bronze.
Methods for the determination of aluminium

AXTU 1709

Date of introduction 1981−01−01

INFORMATION DATA

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

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 10.10.79 N 3899

3. The standard fully complies ST SEV 1532−79

4. REPLACE GOST 1953.7−74*

__________________

* Probably a mistake of the original. Should read: GOST 1953.8−74. — Note the manufacturer’s database.

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)

7. EDITION with Amendments No. 1, 2 approved in February 1983, August 1990 (IUS 6−83, 11−90)

This standard establishes photometric methods for determination of aluminium (from 0.001% to 0.25%) and atomic absorption method for the determination of aluminium (from 0.01% to 0.25%) in tin bronze according to GOST 5017, GOST GOST 614 and 613.

The standard fully complies ST SEV 1532−79.

(Changed edition, Rev. N 1, 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 25086 with the Supplement according to claim 1.1 GOST 1953.1.

(Changed edition, Rev. N 1, 2).

2. The PHOTOMETRIC METHOD for the DETERMINATION of ALUMINIUM WITH ERIOGLAUCINE (from 0.001% to 0.06%)

2.1. The essence of the method

The method is based on formation of colored complex of aluminum with eryhromycin after prior removal of tin in the form of tetrabromide and the separation of aluminium from interfering elements by sodium hydroxide in the presence of butyl alcohol to prevent sorption of aluminum on the hydroxide of the metals.

2.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

a pH meter.

Nitric acid according to GOST 4461.

Hydrochloric acid according to GOST 3118, diluted 1:1 and 1 mol/DMsolution.

Sulfuric acid according to GOST 4204, and diluted 1:1 and 1:50.

Bromatologia acid according to GOST 2062.

The acid chloride.

Acetic acid according to GOST 61.

Bromine according to GOST 4109.

Bromine mixture, freshly prepared; prepared as follows: nine volumes bromatological acid is mixed with one volume of bromine.

Ammonium acetate according to GOST 3117.

Sodium acetate according to GOST 199 and 2 mol/DMsolution.

Sodium hydroxide according to GOST 4328, solutions of 100 and 20 g/DM.

Ammonia water according to GOST 3760 and diluted 1:1.

Buffer solution рН6; prepared as follows: 40 g of ammonium acetate and 18 g of sodium acetate and dissolve in 1 DMof water. Check and set the pH of the solution on the pH meter, by adding sodium hydroxide or acetic acid.

Urea according to GOST 6691.

Eryhromycin R, an aqueous solution 0.7 g/l; prepared as follows: 0.7 g of erioglaucine dissolved in 2 cmof nitric acid with constant stirring for 2 minutes, add 60 cmof water, 0.3 g of urea and incubated for 24 h in a dark place. The solution was filtered in a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix. Store in a dark bottle.

Alum salesonline by ND, a solution of 100 g/DMis prepared as follows: 10 g of alum was dissolved with heating in 70 cmwith the addition of 1 cmof concentrated sulfuric acid and dilute with water to 100 cm.

Normal butyl alcohol according to GOST 6066.

Thioglycolic acid, diluted 1:99, fresh.

Aluminium GOST 11069, brand А999.

Standard solutions of aluminium.

Solution A, prepared as follows: 0.1 g of aluminium is dissolved by heating in 20 cmof hydrochloric acid diluted 1:1. The solution was transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 0.0001 g of aluminum.

Solution B is prepared as follows: 5 cmmortar And transferred to a volumetric flask with a capacity of 100 cm, add 20 cmof hydrochloric acid diluted 1:1, made up to the mark with water and mix.

1 cmof solution B contains 0,00000

5 g of aluminium.

2.3. Analysis

2.3.1. A portion of the alloy (see table.1) is placed in a beaker with a capacity of 250−300 cm, add 10 cmbromine mixture, cover with a watch glass and dissolved under heating. In case of incomplete dissolution, add dropwise bromine. Upon completion of the dissolution solution was poured to 20 cmof perchloric acid and evaporated the solution at a moderate heat to release a thick white smoke of perchloric acid, rinse walls of beaker and watch glass with water and repeat the evaporation until the appearance of dense white smoke of perchloric acid. The solution was then cooled, rinse walls of beaker with water, dissolve salt, add 5 cmof sulphuric acid diluted 1:1, and the solution is evaporated until a white smoke of sulfuric acid.

Table 1

Dissolve the salt by heating in 50 cmof water and filtered off the precipitate of lead sulphate on the filter tight. The filter cake was washed 3−5 times with sulfuric acid, diluted 1:50 and discarded. The filtrate is heated to boiling and the hot solution transferred into a measuring flask with a capacity of 200 cm, rinsing the walls of the beaker with hot water, add 5 cm.of butyl alcohol and stirred. Then the flask was gradually added under good stirring at a charge of 0.25−25 cmof sodium hydroxide solution (200 g/DM) and 20 cmfor hanging of 0.1 g. the Dosage of lye must be accurate. The solution was cooled, the mixture was diluted to the mark with water, mix and leave for sludge precipitation.

The solution was filtered into a dry beaker through a dry thick filter and dry the funnel.

Depending on the mass fraction of aluminum in the test specimen for analysis or use entire filtrate, or select aliquot part (see table.1).

If the analysis uses the entire solution, then filters out all the sediment and washed 2−3 times with sodium hydroxide solution (20 g/DM). The solution was then neutralized with concentrated hydrochloric acid to pH 3 on universal indicator paper and evaporated to a volume of 25 cmand transferred to a volumetric flask with a capacity of 100 cm, rinse walls of beaker with water so that the volume of the solution in the volumetric flask did not exceed 30 cm.

If for analysis use aliquot part (see table.1), then the filtered solution was neutralized to pH 3 with concentrated hydrochloric acid and then do as above.

To the analyzed solution in a volumetric flask with a capacity of 100 cmadd 1 drop of solution of alum salesonline 10 cmof a solution of thioglycolic acid and drop by drop a solution of ammonia until the appearance of violet-staining of thioglycolate iron. Then added dropwise 1 mol/DMsolution of hydrochloric acid to the bleaching solution and excess of this 0.5 cmof excess, add 20 cmof a solution of erioglaucine , 30 cmbuffer solution and dilute to the mark with water. After 20 minutes, measure the optical density of the solution on a photoelectrocolorimeter with a green filter or spectrophotometer at 535 nm in a cuvette of 1 cm with a Solution of comparison is the solution of the control

experience.

2.3.2. Construction of calibration graphs

In a volumetric flask with a capacity of 100 cmplaced 0; 0,5; 1,0; 2,0; 3,0; 4,0 and 5.0 cmof a solution of aluminum, is diluted with water to 30 cmand further analysis are as indicated in claim 2.3.1.

2.4. Processing of the results

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

,

where is the mass of aluminum was found in the calibration schedule g;

 — linkage, the corresponding aliquote part of the solution,

2.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence for 3) specified in table.1A.

Table 1A

(Changed edition, Rev. N 2).

2.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results obtained in the same laboratory but under different conditions (- an indicator of reproducibility) shall not exceed the values specified in table.1A.

2.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.

2.4.3, 2.4.4. (Added, Rev. N 2).

3. The PHOTOMETRIC METHOD for the DETERMINATION of ALUMINUM, CHROMAZUROL AND NEIONOGENNYE SURFACTANTS (0.001% to 0.06%)

3.1. The essence of the method

The method is based on formation of colored complex of aluminum, chromazurol neionogennye and surfactants.

3.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

a pH meter.

Nitric acid according to GOST 4461 and diluted 1:1.

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

The mixture of acids to dissolve, freshly prepared; prepared as follows: mix 100 cmnitrogen, 300 cmof hydrochloric acid and 400 cmof water.

Thioglycolic acid, diluted 1:10, freshly prepared.

Sodium hydroxide according to GOST 4328, a solution of 200 g/DM.

Acetic acid according to GOST 61.

Sodium acetate according to GOST 199.

Buffer solution with a pH of 7; prepared as follows: 100 g of anhydrous or 165 g of crystalline sodium acetate and dissolve in 1 DMof water, and adding acetic acid using pH-meter set pH 7.0.

Sintanol DS-10, allows for the use of OP-10 and OP-7.

Chromazurol , 5·10mol/DMaqueous solution containing 7.5 g/DMof sintanol DS-10 (OP-10, OP-7).

Aluminium GOST 11069, grade A-999 or 9999.

A standard solution of aluminum. Solution A, prepared as follows: 0.1 g of aluminium is dissolved by heating in 20 cmof hydrochloric acid diluted 1:1. The solution was transferred to a volumetric flask with a capacity of 500 cmand topped to the mark with water and mix.

1 cmof the solution contains 0.0002 g of aluminum.

Solution B is prepared as follows: 5 cmsolution And placed in a volumetric flask with a capacity of 500 cm, add 20 cmof hydrochloric acid diluted 1:1, made up to the mark with water and mix.

1 cmof solution B contains 0,000002 grams of aluminum.

Copper metal according to GOST 859, mark M0 or M00.

The copper solution; prepared as follows: 10 g of copper is dissolved in 80 cmof nitric acid, diluted 1:1, and after complete dissolution of the sample is transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and p

peremeshivaya.

3.3. Analysis

3.3.1. A portion of the alloy (see table.2) is placed in a beaker with a capacity of 100−150 cm, add 20 cmof the mixture of acids to dissolve, cover with a watch glass and dissolved under heating. After complete dissolution of the sample solution was cooled, rinse walls of beaker and watch glass with water, the solution transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

Table 2

Aliquot part of the obtained solution (see table.2) is placed in a beaker with a capacity of 50 cm, was added to a solution of copper in the amount indicated in the table.2, diluted to 10 cm, add 7 cmof sodium hydroxide solution, 10 cmthioglycolic acid and stirred until complete dissolution of the precipitate. Then set with sodium hydroxide solution or nitric acid diluted 1:1, рН7 for pH meter or universal indicator paper, add 5 cmof a solution of chromazurol that contains sintanol DS-10 (OP-10, OP-7), 5 cmbuffer solution, transferred to a volumetric flask with a capacity of 50 cm, is diluted to the mark with water, mix and after 30 min measure the optical density in a cuvette with a thickness of absorbing layer 1 cm at a photoelectrocolorimeter FEK-N-57 with red filter No. 8 or on the spectrophotometer at 655 nm against the solution comparison.

For solution comparison in a glass with a capacity of 50 cmis placed 2 cmof copper solution and then act as at the time of evaluation (p.3.3

.1).

3.3.2. Construction of calibration curve

In glasses with a capacity of 50 cmplaced 0; 1,0; 2,0; 3,0; 4,0; 5,0 cmof a solution of aluminium, add 2cmof a solution of copper and further analysis are as specified when running an analysis (p.3.3.1) using the solution comparison solution containing no aluminum.

3.4. Processing of the results

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

,

where - the mass of aluminum was found in the calibration schedule g;

- the weight of the portion corresponding to aliquots of the solution taken for analysis,

3.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence) as shown in table.1A.

(Changed edition, Rev. N 2).

3.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results obtained in the same laboratory but under different conditions (- an indicator of reproducibility) shall not exceed the values specified in table.1A.

3.4.4. Control of accuracy of analysis results is carried out as specified in clause 2.4.4.

3.4.3, 3.4.4. (Added, Rev. N 2).

4. The PHOTOMETRIC METHOD for the DETERMINATION of ALUMINIUM (from 0.01% to 0.25%)

4.1. The essence of the method

The method is based on the formation of the aluminum complex compounds colored with eryhromycin and the measurement of its optical density after the separation of copper by electrolysis.

4.2. Apparatus, reagents and solutions

Installation for electrolysis with platinum electrodes according to GOST 6563.

a pH meter.

Photoelectrocolorimeter or spectrophotometer.

Nitric acid according to GOST 4461 and diluted 1:1.

Hydrochloric acid according to GOST 3118, diluted 1:1 and 1 mol/DMsolution.

Bromatologia acid according to GOST 2062.

Ascorbic acid, freshly prepared solution of 10 g/DM.

Acetic acid according to GOST 61.

Thioglycolic acid, diluted 1:99, fresh.

Bromine according to GOST 4109.

The mixture for dissolving freshly prepared; prepared as follows: 9 parts bromatological acid mixed with one part of bromine.

Ammonia water according to GOST 3760, diluted 1:1 and 1:10.

Ammonium chloride according to GOST 3773 and a solution of 20 g/DM.

Ammonium acetate according to GOST 3117.

Sodium hydroxide (caustic soda) according to GOST 4328, 1 mole/DMsolution.

Sodium acetate according to GOST 199 and 2 mol/DMsolution.

Sodium Chernovetskiy by ND, a solution of 50 g/DM.

Urea according to GOST 6691.

Alum salesonline by ND, a solution of 100 g/l; prepared as follows: 10 g of alum was dissolved with heating in 70 cmwater and 2 cmof sulphuric acid diluted 1:1, and the solution is diluted with water to 100 cm.

Buffer solution with рН6 prepared as follows: 46 g ammonium acetate and 18 g of sodium acetate dissolved in 1000 cmof water. Set the pH of the solution on the pH meter, by adding sodium hydroxide solution or acetic acid.

Eryhromycin , the aqueous solution 7 g/DM; prepared as follows: 0.7 g of erioglaucine dissolved in 2 cmof concentrated nitric acid with constant stirring for 2 minutes Add 60 cmof water, 0.3 g of urea and incubated for 24 h in a dark place. The solution was filtered into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix. Store in a dark bottle.

Aluminium GOST 11069 with a mass fraction of aluminum of not less than 99.9%.

Standard solutions of aluminium.

Solution A, prepared as follows: 0.1 g of aluminium is dissolved by heating in 20 cmof hydrochloric acid diluted 1:1. The solution is 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 0.0001 g of aluminum.

Solution B is prepared as follows: 5 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 20 cmof hydrochloric acid diluted 1:1, made up to the mark with water and mix.

1 cmof solution B contains 0,

000005 g of aluminum.

4.3. Analysis

4.3.1. A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 300 cmand dissolved in 15 cmof the mixture to dissolve when heated. After dissolving, the solution was evaporated to dryness. Repeat two more times adding 15 cmof the mixture for dissolution and evaporation to dryness.

To the dry residue add 10 cmof concentrated nitric acid, the solution evaporated to a wet residue and this operation is repeated two times. To wet, chilled to the residue add 10 cmof nitric acid, diluted 1:1, diluted with water to a volume of 150 cmand produce copper by electrolysis according to GOST 1953.1. The electrolyte is added 2 g of ammonium chloride, 1 cmgentoomaniac alum solution, heated to 50−60 °C and ammonia is added, diluted 1:1 before precipitation of the hydroxides of iron and aluminum. Solution and the precipitate is kept in a warm place for 10−15 min, the solution was filtered on a loose filter, and the precipitate was washed 5−6 times with a solution of ammonium chloride. The washed precipitate is washed from the filter with a jet of hot water into the Cup, which was held a deposition, the filter was washed first 3 cmof hot hydrochloric acid diluted 1:1 and then with hot water and the solution was heated until complete dissolution of the precipitate. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. Depending on the aluminum content selected aliquot part of the solution (table.3) and placed in beaker or volumetric flask with a capacity of 100 cm.

Table 3

To aliquote part of the solution in the volumetric flask, add water up to 20 cm, 10 cmsolution of thioglycolic acid, ammonia, diluted 1:1 before the appearance of the staining of thioglycolate iron, then add 1 mol/DMsolution of hydrochloric acid to the bleaching solution and 0.5 cmof excess acid. Add 20 cmof a solution of erioglaucine , 30 cmbuffer solution, made up to the mark with water and mix.

When establishing the pH of the solution at the pH meter to aliquote part of the solution in the beaker add water to 20 cm, 2 cmof ascorbic acid solution, 5 cmof a solution of sodium servational after 5−10 min, add 20 cmof a solution of erioglaucine and set рН6 for pH meter with ammonia diluted 1:1. The solution was transferred to a volumetric flask with a capacity of 100 cm, add 30 cmbuffer solution, made up to the mark with water and mix. After 20 minutes, measure the optical density of the solution on a photoelectrocolorimeter with a green optical filter in a cuvette with a thickness of the absorbing layer 2 cm or on the spectrophotometer at a wavelength of 535 nm in a cuvette with a thickness of absorbing layer 1 cm.

Solution comparison is the solution kontrolnog

on experience.

4.3.2. Construction of calibration curve

In five of the six beakers or volumetric flasks with a capacity of 100 cmis placed 1,0; 2,0; 3,0; 4,0 and 5,0 cmstandard solution B aluminum. All beakers or flasks add up to 20 cmwater, 10 cmof a solution of thioglycolic acid or 2 cmof the ascorbic acid solution and further analysis are as indicated in claim 4.3.1. Solution comparison is the solution not containing aluminum. According to the obtained results build a calibration curve.

4.4. Processing of the results

4.4.1. Mass fraction of aluminium () in percent is calculated by the formula

,

where - the mass of aluminum was found in the calibration schedule g;

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

4.1−4.4.1. (Changed edition, Rev. N 1).

4.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence for 3) specified in table.1A.

(Changed edition, Rev. N 2).

4.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results obtained in the same laboratory but under different conditions (- an indicator of reproducibility) shall not exceed the values specified in table.1A.

4.4.4. Control the accuracy of the results of the analysis carried out as specified in clause 2.4.4.

4.4.3, 4.4.4. (Added, Rev. N 2).

5. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF ALUMINIUM

5.1.The essence of the method

The method is based on measurement of light absorption by atoms of aluminium produced during the introduction of the analyzed solution in the flame acetylene-nitrous oxide.

5.2. Apparatus, reagents and solutions

Atomic absorption spectrometer with a radiation source for aluminium.

Installation for electrolysis with platinum electrodes according to GOST 6563.

Nitric acid according to GOST 4461 and diluted 1:1.

Hydrochloric acid according to GOST 3118 and 2 mol/DMsolution.

Bromatologia acid according to GOST 2062.

Bromine according to GOST 4109.

The mixture for dissolving freshly prepared; prepared as follows: 9 parts bromatological acid mixed with one part of bromine.

Hydrogen peroxide (perhydrol) according to GOST 10929.

Aluminium GOST 11069, with a mass fraction of aluminum of not less than 99.9%.

Standard solutions of aluminium.

Solution A, prepared as follows: 0.5 g of aluminium is dissolved by heating in 20 cmof hydrochloric acid with the addition of 2−3 cmof hydrogen peroxide. Remove excess hydrogen peroxide by boiling, the solution was cooled, transferred to a volumetric flask with a capacity of 500 cmand top up with water to the mark.

1 cmof the solution contains 0.001 g of aluminium.

Solution B is prepared as follows: 10 cmof the solution And transferred to a volumetric flask with a capacity of 100 cm, add 10 cmof 2 mol/DMhydrochloric acid solution and add water to the mark.

1 cmof a solution contains 0.0001 g aluminum

niya.

5.3. Analysis

5.3.1. A sample of alloy weighing 1 g is placed in a beaker with a capacity of 250 cmand carefully add 15 cmof the mixture for dissolution. After dissolution the solution cautiously evaporated to dryness. Evaporation with 15 cmof the mixture to dissolve is repeated twice more, evaporating in each case the solution to dryness. To the dry residue add 10 cmof nitric acid and evaporated to syrupy state. Repeat the evaporation with 10 cmof nitric acid, diluted with water to a volume of 150 cmand the electrolysis is carried out according to GOST 1953.1.

The electrolyte is evaporated to a volume of 10 cm, cooled, transferred to a volumetric flask with a capacity of 50 cmand top up with water to the mark. Measure the atomic absorption of aluminum in the flame acetylene-nitrous oxide at a wavelength of 309,3 nm parallel to the calibration solutions

I.

5.3.2. Construction of calibration curve

Ten of the eleven volumetric flasks with a capacity of 100 cmis placed 1,0; 2,5; 5,0; 10,0 and 15,0 cmstandard solution B aluminum; 2,0; 3,0; 4,0; 5,0 and 6,0 cmstandard solution And aluminum. To all flasks add 10 cmof 2 mol/DMhydrochloric acid solution, made up to the mark with water and measure the atomic absorption of aluminum, as specified in clause 5.3.1. According to the obtained results build a calibration curve.

5.4. Processing of the results

5.4.1. Mass fraction of aluminium () in percent is calculated by the formula

,

where is the concentration of aluminum was found in the calibration schedule, g/cm;

- the volume of the final solution, cm;

- the weight of the portion of the sample,

5.1−5.4.1. (Changed edition, Rev. N 1).

5.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (the rate of convergence for 3) specified in table.1A.

(Changed edition, Rev. N 2).

5.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results obtained in the same laboratory but under different conditions (- an indicator of reproducibility) shall not exceed the values specified in table.1A.

5.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained one of the photometric methods in accordance with GOST 25086.

5.4.3, 5.4.4. (Added, Rev. N 2).

6. The PHOTOMETRIC METHOD for the DETERMINATION of ALUMINUM, CHROMAZUROL S (from 0.001% to 0.06%)

6. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF ALUMINIUM
With CHROMAZUROL (from 0.001% to 0.06%)

6.1. The essence of the method

The method is based on formation of colored complex of aluminum, chromazurol and measurement of its optical density after prior removal of tin in the form of tetrabromide, the separation of copper by electrolysis or separation of interfering elements by thioacetamide.

6.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

a pH meter.

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

Hydrochloric acid according to GOST 3118, diluted 1:1, 1:100, and a solution of 0.1 mol/DM.

The acid chloride.

Bromatologia acid according to GOST 2062.

Bromine according to GOST 4109.

Mix to dissolve: nine volumes bromatological acid is mixed with one volume of bromine.

Acetic acid according to GOST 61.

Thioglycolic acid, diluted 1:20, freshly prepared.

Ammonia water according to GOST 3760, diluted 1:1 and 1:3.

Gelatin, a solution of 10 g/DM.

Ammonium acetate according to GOST 3117.

Sodium acetate.

Buffer a solution of 46 g ammonium acetate and 18 g of sodium acetate and dissolve in 1 DMof water. Set pH to 5.7−5.8 pH-meter, if necessary, add solution of ammonia or acetic acid.

Thiourea according to GOST 6344, solution 100 g/DM.

The thioacetamide solution is 50 g/DM.

Rectified ethyl alcohol according to GOST 18300.

Chromazurol , the solution of 3 g/DM: 0.3 g of chromazurol dissolved in 30 cmof warm water (above 60 °C), 20 cmof ethyl alcohol, filter and add water in a flask with a capacity of 100 cmmark.

Aluminium GOST 11069, brand А999 or A99.

Standard solutions of aluminium.

Solution a: 0.1 g of aluminium is dissolved by heating in 20 cmof hydrochloric acid (1:1), the solution transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 0.0001 g of aluminum.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 10 cmof hydrochloric acid (1:1), made up to the mark with water and mix.

1 cmof solution B has the 0.00001 g of aluminum.

Solution: 25 cmsolution And placed in a volumetric flask with a capacity of 500 cm, add 10 cmof hydrochloric acid (1:1), made up to the mark with water and mix.

1 cmof the solution contains 0,000

005 g of aluminum.

6.3. Analysis

6.3.1. For bronzes containing lead as an impurity

A portion of the alloy 0.5 g were placed in a glass with a capacity of 250−300 cm, add 20 cmof the mixture to dissolve and dissolve on the cold. Add 20 cmof perchloric acid and distilled tin under moderate heat to start the selection, the dense white smoke of perchloric acid and clarification of the solution. If the solution is not transparent, the Stripping of tin with bromine a mixture of repeat.

The side of the Cup then rinsed with water and the solution is evaporated to wet salts. Then the side of the Cup and rinse with water, add 5 cmof sulphuric acid (1:1) and the solution evaporated to dryness. Salt is dissolved in 7 cmprokopchina nitric acid (1:1), add 150 cmof water, heated to 60−70 °C and carry out the electrolysis at a current of 0,5−1 A and a voltage of 2 V. the Electrolyte is evaporated to wet salts, add 5 cmof hydrochloric acid (1:1), the solution transferred to a volumetric flask with a capacity of 50 cmand up to the mark and top up with water.

Depending on the mass fraction of aluminium in bronze in a glass with a capacity of 100 cmis taken aliquot part of the solution: 25 cm(from 0.001% to 0.01%), 10 cm(from 0.01% to 0.02%), 5 cm(from 0,02% to 0,04%), 2.5 cm(from 0.04% to 0.06%) and is evaporated almost to dryness. To the residue add 5 cmof hydrochloric acid (0.1 mol/l) and heated until dissolved. Then diluted with water to 30 cm, add 1 cmof a solution of thiourea, 3 cmof a solution of thioglycolic acid and set pH=4 to pH meter ammonia solution (1:3) or via a universal paper. Then add 10 cmgelatin solution, 3 cmof a solution of chromazurol and the solution is placed in a volumetric flask with a capacity of 100 cm, add a 40 cmbuffer solution, topped up to the mark with water and mix.

After 40−50 min, measure the optical density of the solution on a photoelectrocolorimeter with a green filter (=540−560 nm) or on a spectrophotometer at 545 nm in cuvettes with the thickness of the absorbing layer 2, or 1 cm relative to the control experiment conducted using

the entire course of the analysis.

6.3.2. For bronzes containing lead as a component

Dissolution of the sample and Stripping of tin is carried out as specified in clause 3.3.1.

To wet salts, add 5 cmof hydrochloric acid (1:1) and the solution evaporated to dryness. The evaporation is repeated 2 times, each time adding 5 cmof hydrochloric acid (1:1). To the dry residue add 2.5 cmof concentrated hydrochloric acid, 50 cmof water, the solution is heated and the hot solution was added 15 cmof thioacetamide under stirring, the solution was heated to boiling and boiled for 20 min. Leave the solution on the warm bath for 1 h. the precipitate is Then filtered on the filter medium density with the addition of a small amount filtrowanie mass. The precipitate is washed with hydrochloric acid (1:100) 10 times, the precipitate is discarded and the filtrate is evaporated to 3−5 cm. The solution was cooled and transferred to volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

Select aliquot part of the solution (p.3.3.1) was placed in a beaker with a capacity of 100 cm, add water to 30 cm, 3 cmthioglycolic acid and set pH=4, pH meter ammonia solution (1:3) or via a universal paper. Then add 5 cmof gelatin solution, 3 cmof a solution of chromazurol and the solution transferred to a volumetric flask with a capacity of 100 cm, add a 40 cmbuffer solution, topped up to the mark with water and mix. After 40−50 min, measure the optical density of the solution on a photoelectrocolorimeter with a green filter (=540−560 nm) or on a spectrophotometer at 545 nm in a cuvette with the thickness of the absorbing layer 2, or 1 cm relative to the control experiment conducted using the whole analysis, but with the addition of 2 cmof tio

acetamide.

6.3.3. Construction of calibration graphs

6.3.3.1. For bronzes containing aluminum from 0.001% to 0.005%

In a volumetric flask with a capacity of 100 cmis placed 0; 0,5; 1,0; 2,0 and 2,5 cmstandard solution In aluminum, add 5 cmof hydrochloric acid solution (0.1 mol/DM), water to a volume of 30 cmand then received, as indicated in paragraph 3.3.1 or 3.3.2. Solution comparison is the solution not containing aluminum. The cuvette with the thickness of the absorbing layer 2 see

6.3.3.2. For bronzes containing aluminum in excess of 0,005%

In a volumetric flask with a capacity of 100 cmis placed 0; 0,5; 1,0; 1,5; 2,0 and 2,5 cmstandard solution B aluminum, add 5 cmof hydrochloric acid solution (0.1 mol/DM), water to a volume of 30 cmand then received, as indicated in paragraph 3.3.1 or 3.3.2, only the gelatin solution are added 5 cm. Solution comparison is the solution not containing aluminum. The cuvette with the thickness of absorbing layer 1 cm*.
_______________
* Consistent with the original. — Note the «CODE»

.

6.4. Processing of the results

6.4.1. Mass fraction of aluminium () in percent is calculated by the formula

,

where is the mass of aluminum was found in the calibration schedule g;

- the mass corresponding to aliquote part of the solution,

6.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence for 3) specified in table.1A.

6.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values specified in table.1A.

6.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.

6.4.5. Photometric with chromazurol method is applied in case of disagreement in assessing the quality of tin bronzes.

Sec. 6. (Added, Rev. N 2).