GOST 11739.13-98

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  ГОСТ 11739.13-98

GOST 11739.13−98 Alloys, aluminum casting and wrought. Methods for determination of copper

GOST 11739.13−98

Group B59

INTERSTATE STANDARD

ALLOYS ALUMINIUM CAST AND WROUGHT

Methods for determination of copper

Aluminium casting and wrought alloys. Methods for determination of copper

ISS 77.120.10
AXTU 1709

Date of implementation 2000−01−01

Preface

1 DEVELOPED by JSC «Russian Institute of light alloys» (JSC VILS), the Interstate technical Committee MTC 297 «Materials and semi-finished products from light and special alloys"

INTRODUCED by Gosstandart of Russia

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol of 12 November 1998 No. 14−98)

The adoption voted:

3 Resolution of the State Committee of the Russian Federation for standardization and Metrology, dated April 21, 1999 No. 132 inter-state standard GOST 11739.13−98 introduced directly as state standard of the Russian Federation from January 1, 2000

4 REPLACE GOST 11739.13−82

5 REISSUE. August 2002

1 Scope

This standard specifies electrogravimetry (with a mass fraction of from 0.5 to 12.0%), photometric (with a mass fraction of from 0.002 to 0.8%) and atomic absorption (at a mass fraction of from 0.005 to 8.0%) methods for determination of copper.

2 Normative references

The present standard features references to the following standards:

GOST 859−2001 Copper. Brand

GOST 3118−77 hydrochloric Acid. Specifications

GOST 3652−69 citric Acid monohydrate and anhydrous. Specifications

GOST 3759−75 Aluminium chloride 6-water. Specifications

GOST 3760−79 Ammonia water. Specifications

GOST 4204−77 sulfuric Acid. Specifications

GOST 4328−77 Sodium hydroxide. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 5457−75 Acetylene, dissolved and gaseous. Specifications

GOST 5841−74 Hydrazine sulfate

GOST 6563−75 technical articles made of noble metals and alloys. Specifications

GOST 9656−75 boric Acid. Specifications

GOST 10484−78 hydrofluoric Acid. Specifications

GOST 10929−76 Hydrogen peroxide. Specifications

GOST 11069−74 Aluminium primary. Brand

GOST 18300−87 ethyl rectified technical. Specifications

GOST 25086−87 non-ferrous metals and their alloys. General requirements for methods of analysis

3 General requirements

3.1 General requirements for methods of analysis GOST 25086 with the Supplement.

3.1.1 the result of the analysis be the arithmetic mean of results of two parallel measurements.

4 Electrogravimetry method for the determination of copper

4.1 the essence of the method

The method is based on dissolving the sample in a mixture of perchloric and nitric acids, dehydration and coagulation of silicon, the destruction of its transport in the form of tetrafluoride, the electrolytic release of copper from the nitric acid environment in the presence of the reducing agent is hydrazine sulphate and weighing. Interfere with the determination of tin, antimony and bismuth.

4.2 Equipment, reagents and solutions

Laboratory apparatus for electrolysis provided with a device for mixing the electrolyte (rotating anode, magnetic stirrer or bubbler).

The electrodes of the Fisher mesh platinum according to GOST 6563.

Drying oven with thermostat.

Oven muffle.

Acid chloride with a density of 1.67 g/cmand a solution of 1:1 [1].

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

Sulfuric acid according to GOST 4204 density 1.84 g/cm.

Hydrofluoric acid according to GOST 10484.

Hydrazine sulfate according to GOST 5841.

The technical rectified ethyl alcohol according to GOST 18300 (10 cmfor one definition).

Adsorbent (materiana paper): 100 g of crushed filters (red ribbon) is placed in a beaker with a capacity of 500 cm, 300 cm pouredhot water and stirred with a stirrer to obtain a homogeneous mass.

4.3 Preparation for analysis

Before using the mesh cathode is calcined at a temperature of 800−900°C for 3−5 min, then cooled. The cathode is immersed in ethyl alcohol, dried in a drying Cabinet at a temperature of 100−110°C for 1−2 min, placed in a desiccator and after cooling to room temperature, weighed.

4.4 analysis

4.4.1 the sample the sample was placed in a beaker with a capacity of 400 cmand carefully, in small portions pour the mixture of perchloric and nitric acids (see table 1).

Table 1

After finishing the reaction the solution was evaporated to release the abundant white fumes of perchloric acid and heating was continued for 15−20 min.

To a cold draft poured 200 cmof hot water, gently stirred, heated to dissolve the salts and maintained at a temperature of 40−60°C for 30 min.

Solution and the precipitate was filtered through a filter medium density («white ribbon») with the adsorbent, and the precipitate was washed with 400−500 cmof hot water collecting the filtrate and washings in the same beaker (stock solution).

The filter with precipitate was placed in a platinum crucible, dried, incinerated, preventing ignition, and calcined at a temperature of 500−550°C for 5 min. After cooling in the crucible add ten drops of sulphuric acid, 5 cmhydrofluoric acid and drop by drop nitric acid (approximately 1−2 cm) to obtain a transparent solution. The solution was evaporated to dryness, the dry residue poured 5cmof hot water, 1 cmof perchloric acid and dissolved with moderate heating. After cooling, the solution is attached to the main solution in the beaker (if necessary, filtered).

4.4.2 the Solution was evaporated to a volume of 160−170 cm, pour 5 cmof nitric acid, add 0.2 g of hydrazine sulfate and heated to a temperature of 60−70°C. the resulting solution was immersed the electrode and, constantly stirring, it is subjected to electrolysis mode: the current density of 1.5−2.0 And on 1 DMsquare of the cathode and a voltage of 2−2. 5 V.

The electrolysis was carried out for 25−30 min until then, until the solution become colourless. To monitor the completeness of copper deposition at the cathode, the electrolyte level increases by 1 cm by adding water and subjecting the solution to electrolysis for a further 10−15 min. the Electrolysis is complete, if on the newly immersed surface of the cathode not being singled out copper. Without turning off the current, remove the glass with the electrolyte and quickly replace it with chemical glass of water, the water must completely cover the electrodes.

Then a glass of water is removed, current is turned off, disconnecting the electrodes from the electrolytic cell, and then rinse the cathode in a quick immersion in ethanol, dry it in a drying Cabinet at a temperature of 100−110°C for 1−2 min, placed in a desiccator and after cooling to room temperature, weighed.

For subsequent use by the cathode are immersed in a warm solution of nitric acid to dissolve the copper, then thoroughly washed with water and then act in accordance with 4.3.

4.5 Processing of results

4.5.1 Mass fraction of copper , %, is calculated by the formula

, (1)

where is the mass of the cathode after electrolysis, g;

 — the mass of the cathode before electrolysis, g;

 — the weight of the portion of the sample,

4.5.2 discrepancies in the results must not exceed the values given in table 2.

Table 2

Percentage

5 Electrogravimetry rapid method for determination of copper

5.1 the essence of the method

The method is based on dissolving the sample in a mixture of nitric, hydrofluoric and sulphuric acids, the electrolytic release of copper and weighing. The definition prevents the bismuth.

5.2 the Instrument, reagents and solutions

Laboratory apparatus for electrolysis provided with a device for mixing the electrolyte (rotating anode, magnetic stirrer or bubbler).

The electrodes of the Fisher mesh platinum according to GOST 6563.

Drying oven with thermostat.

Oven muffle.

Hydrofluoric acid according to GOST 10484.

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

Sulfuric acid according to GOST 4204 density 1.84 g/cm.

A mixture of acids N 1: 500 cmwater flow of 300 cmof nitric acid and carefully, portions 200 cmof sulphuric acid, the mixture was stirred and cooled to room temperature.

A mixture of acids N 2: to 100 cmhydrofluoric acid carefully poured 30 cmnitrogen and 20 cmof sulphuric acid, the mixture was stirred and cooled to room temperature. The mixture is prepared and stored in a plastic container.

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 solution is prepared and stored in a plastic container.

A saturated solution of boric acid: 60 g boric acid dissolve in 1 DMof hot water, the solution was cooled to room temperature and stirred.

The technical rectified ethyl alcohol according to GOST 18300 (10 cmfor one definition).

Hydrazine sulfate according to GOST 5841, solution 100 g/DM.

5.3 Preparation for analysis — 4.3.

5.4 analysis

5.4.1 the sample the sample weight of 2 g for the mass concentration of copper is less than 1.0% or 1 g when the mass fraction of copper over 1.0% depending on the mass fraction of silicon dissolved one of the following ways.

5.4.1.1 When the mass fraction of silicon is less than 1.5%

Weighed samples placed in a glass beaker with a capacity of 250 cm, 40 cm, pour themixture of acids N 1 and heated to start the reaction, and then heating was stopped. When the majority of the sample will dissolve and the reaction will slow down, wash the walls of the beaker with water to the original volume, poured 2 cmbridgestation acid at mass fraction of silicon up to 0.5%, 5 cmbridgestation acid at mass fraction of silicon up to 1.5% and again moderately heated until a clear solution. Solution add water to volume of 160−170 cm.

5.4.1.2 When the mass fraction of silicon more than 1.5%

Weighed samples were placed in a glass of glassy carbon or PTFE with a capacity of 100−150 cmand pour the mixture of acids N 2: 40 cmfor sample of sample 1 g or 60 cmfor hanging samples weighing 2 g; a mixture of acids first poured dropwise until the cessation of the violent reaction, then — in portions of 3−5 cm.

The contents of the beaker heated for 10−15 minutes, pour 50 cmof boric acid solution and transfer the solution to a glass beaker with a capacity of 200−250 cm. Wall Teflon beaker is washed with a boric acid solution: 50 cmfor attachment of a sample weighing 1 g or 100 cmfor the mounting of the sample mass of 2 g and added to the solution in a glass beaker. The contents of the Cup moderately heated to obtain clear solution and add water to volume of 160−170 cm.

5.4.1.3 Solution 5.4.1.1 or 5.4.1.2 heated to a temperature of 60−70°C and then act on 4.4.2.

5.5 processing of the results — for 4.5.

6 Photometric method for the determination of copper

6.1 the essence of the method

The method is based on dissolving the samples in hydrochloric acid formation at pH 9 blue complex compound of copper with cuprizone and measuring the optical density of the solution at a wavelength of 595 nm.

6.2 Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Oven muffle.

Hydrochloric acid according to GOST 3118 density of 1.19 g/cmand a solution of 1:1, 1:99.

Sulfuric acid according to GOST 4204 density 1.84 g/cm.

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

Ammonia water according to GOST 3760.

Citric acid according to GOST 3652, a solution of 500 g/DM.

Sodium hydroxide according to GOST 4328, a solution of 0.5 mol/DM.

Hydrofluoric acid according to GOST 10484.

Boric acid according to GOST 9656.

Acid bridgestoneturanza at 5.2.

Buffer solution of sodium borate, pH 9: 13,45 g of boric acid were placed in a glass with a capacity of 500 cm, 350 cm pouredwater and dissolved by heating. The solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 500 cm, flow 65 cmof sodium hydroxide solution, made up to the mark with water and mix.

The neutral red indicator solution 1 g/DM.

The technical rectified ethyl alcohol according to GOST 18300, solution 1:1.

Bis-(cyclohexanone)-oxalidaceae (cuprizone) [2]* a solution of 5 g/DM: 0.25 g cuprizone placed in a volumetric flask with a capacity of 50 cm, is dissolved in 40 cmof ethyl alcohol, pour the alcohol solution up to the mark and mix.
________________
* See Bibliography. — Note the manufacturer’s database.


Copper according to GOST 859 brand M00.

Standard solutions of copper

Solution a: 1 g of copper is placed in a tall beaker with a capacity of 400 cm, flow 20 cmwater and 10 cmof nitric acid, cover the beaker watch glass and dissolved under heating.

The solution was evaporated on a water bath until the onset of crystallization, pour 50 cmof water and dissolved salts at a moderate heat. 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 cmof the solution contains 0.001 g of copper.

Solution B: 50 cmsolution And 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 of 0.00005 g of copper.

Solution: 10 cmof a solution transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0,000005 g of copper.

Solutions B and C were prepared before use.

6.3 analysis

6.3.1 Sample the sample weight in accordance with table 3, depending on the mass fraction of silicon dissolved one of the following ways.

Table 3

6.3.1.1 When the mass fraction of silicon is less than 1.5%

Weighed sample is placed in a conical flask with a capacity of 250 cmand poured in small portions 30 cmof a hydrochloric acid solution 1:1. After the cessation of violent reaction poured 2 or 5 cmbridgestation acid (depending on the mass fraction of silicon), cover the flask with a watch glass or funnel and continue dissolving with a moderate heat. Then add drop by drop nitric acid to dissolve sample (from about three to twenty drops, depending on the mass fraction of copper), wash the walls of the bulb 20−30 cmof water and boil the solution for 2−3 min.

The solution was cooled, transferred into a measuring flask with volume capacity in accordance with table 3, made up to the mark with water and mix.

6.3.1.2 When the mass fraction of silicon more than 1.5%

Weighed sample is placed in a conical flask with a capacity of 250 cm, poured in small portions 30 cmof a hydrochloric acid solution of 1:1 and dissolve the sample at room temperature. After the cessation of violent reaction cover the flask with a watch glass and continue dissolving with a moderate heat. Then add drop by drop nitric acid to dissolve sample (from about three to twenty drops, depending on the mass fraction of copper). The solution is carefully evaporated to wet salts, pour 15 cmof a hydrochloric acid solution of 1:1, approximately 30−40 cmof hot water and dissolve salt.

The solution was filtered into a measuring flask with volume capacity in accordance with table 3 through the filter medium density («white ribbon»), twice the filter is washed with hydrochloric acid 1:99 in portions of 10 cm, collecting the filtrate in the same flask (stock solution).

The filter with precipitate was placed in a platinum crucible, dried, incinerated completely, preventing ignition, and calcined at 500−600°C for 5−10 min. After cooling in the crucible add five drops of sulfuric acid, 5 cmhydrofluoric acid and drop by drop nitric acid (approximately 1 cm) to obtain a transparent solution. The solution was evaporated to dryness, cooled, poured to the dry residue in the crucible is 5 cm.of hydrochloric acid 1:1, dissolve the residue poured 5cmof water and stirred. If necessary, the solution was filtered through a small tight filter («blue ribbon») and added to the main solution. Stock solution in a volumetric flask in accordance with table 3 top up with water to the mark and mix.

6.3.2 Aliquot part of the solution in accordance with table 3 is placed in a volumetric flask with a capacity of 50 cm, pour 2 cmof a solution of citric acid, add one drop of neutral red solution from the burette, slowly while stirring, pour the ammonia to red color transition of the indicator in a pale yellow (approximately 2−3 cmof ammonia) and of 1 cmof ammonia in excess. Then pour 5 cmof buffer solution with pH 9, 1 cmof solution cuprizone, made up to the mark with water and mix.

6.3.3 Optical density of the solution is measured after 15 min at a wavelength of 595 nm in a cuvette with a layer thickness of 30 mm. with a Solution of comparison is the solution of the reference experiment, which is prepared according to 6.3.1.1, 6.3.1.2 and 6.3.2 with all the reagents used in the analysis.

Mass of copper is determined according to the calibration schedule.

6.3.4 Construction of calibration curve

In seven of the eight volumetric flasks with a capacity of 50 cmmeasure 0,5; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 cmstandard solution, which corresponds to 0,0000025; 0,000005; 0,00001; 0,00002; 0,00003; 0,00004; 0,00005 g of copper in each flask pour approximately 10 cmof water, 2 cmof a solution of citric acid and continue in 6.3.2 and 6.3.3. Solution comparison is the solution, in which copper has not been introduced.

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

6.4 Processing of results

6.4.1 Mass fraction of copper , %, is calculated by the formula

, (2)

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

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

6.4.2 Divergence of results should not exceed the values given in table 4.

Table 4

Percentage

7 Atomic absorption method for determination of copper

7.1 the essence of the method

The method is based on dissolving the samples in hydrochloric acid and measuring the atomic absorption of copper at a wavelength of 324,8 nm in the flame acetylene-air.

7.2 Apparatus, reagents and solutions

Spectrophotometer of atomic absorption with a radiation source of copper.

Oven muffle.

Drying oven with thermostat.

Copper according to GOST 859 brand M00.

Standard solutions of copper

Solution a, prepared according to 6.2.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.0001 g of copper.

Solution B is prepared before consumption.

Hydrochloric acid according to GOST 3118 density of 1.19 g/cm, mortar 1:1 and 1:99.

Aluminium chloride 6-water according to GOST 3759.

A solution of aluminum 20 g/DM: 90 g aluminum chloride are dissolved in 200 cmof a hydrochloric acid solution of 1:1, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

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

Sulfuric acid according to GOST 4204 density 1.84 g/cm.

Acetylene according to GOST 5457.

Hydrofluoric acid according to GOST 10484.

Hydrogen peroxide according to GOST 10929.

Aluminium GOST 11069 brand А999.

7.3 analysis

7.3.1 the weight of the sample weight in accordance with table 5 was placed in a conical flask with a capacity of 250 cm, 30 cm, pour thewater in small portions 30 cmof a hydrochloric acid solution of 1:1 and dissolving the sample first at room temperature, then with moderate heat. The solution was added dropwise 1−2 cmof nitric acid, carefully evaporated to wet salts, poured 20 cmof a hydrochloric acid solution of 1:1, 50−60 cmof hot water, dissolve the salt by heating, the solution was cooled and stirred.

Table 5

7.3.1.1 If the solution is clear, he was transferred to volumetric flask with a capacity in accordance with table 5, made up to the mark with water and mix.

7.3.1.2 If there is a precipitate, indicating the presence of silicon, the solution was filtered into a measuring flask with volume capacity in accordance with table 5 through the filter medium density («white ribbon») and the filter washed twice with hydrochloric acid 1:99 (stock solution).

The filter with precipitate was placed in a platinum crucible, dried, incinerated, preventing ignition, and calcined at 500−600°C for 3−5 min. After cooling in the crucible add five drops of sulfuric acid, 5 cmhydrofluoric acid and drop by drop nitric acid (approximately 1 cm) to obtain a transparent solution.

The solution was evaporated to dryness, cooled, poured to the dry residue in the crucible is 3 cmof a solution of hydrochloric acid 1:1, dissolve the residue when it is heated, pour 5 cmof water, stirred, if necessary, filtered through a small, dense filter («blue ribbon»), attached to the main solution, made up to the mark with water and mix.

7.3.1.3 When the mass fraction of copper of more than 1% aliquot part of the solution was 10 cm,transferred to a volumetric flask with a capacity of 100 cm, 8 cm pour thehydrochloric acid solution of 1:1, made up to the mark with water and mix.

7.3.2 Solution of the reference experiment is prepared according 7.3.1 using is sample the sample the sample of aluminium.

7.3.3 Construction of calibration graphs

7.3.3.1 When the mass fraction of copper from 0.005 to 0.05%

In seven volumetric flasks with a capacity of 100 cmpour 50 cmof a solution of aluminum in six of them measure 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution B, which corresponds to 0,00005; 0,0001; 0,0002; 0,0003; 0,0004; 0,0005 g of copper.

7.3.3.2 When the mass fraction of copper of St 0.05 to 1.0%

Eight volumetric flasks with a capacity of 100 cmpour 5 cmof a solution of aluminium, 6 cmof a hydrochloric acid solution of 1:1, in seven of them measure 0,5; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 cmstandard solution B, which corresponds to 0,00005; 0,0001; 0,0002; 0,0004; 0,0006; 0,0008; 0,001 g of copper.

7.3.3.3 If the mass fraction of copper of St. 1.0 to 8.0%

In seven volumetric flasks with a capacity of 100 cmflow for 0.5 cmof a solution of aluminium, 8 cmof a hydrochloric acid solution of 1:1, in six of them measure 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 cmstandard solution B, which corresponds to 0,0001; 0,0002; 0,0004; 0,0006; 0,0008; 0,001 g of copper.

7.3.3.4 Solutions for 7.3.3.1−7.3.3.3 poured into the flasks to the mark with water and mix.

7.3.4 sample Solution, solution control experience and solutions to build the calibration curve is sprayed into the flame of acetylene-air and measure the atomic absorption of copper at a wavelength of 324,8 nm.

According to the obtained values of atomic absorption and corresponding mass concentrations of copper to build a calibration curve in the coordinates «Value of atomic absorption — mass concentration of copper, g/cm». The solution, in which copper has not been introduced, serves as a solution control experience in construction of calibration curve.

Mass concentration of copper in sample solution and in the solution of control and experience determined by the calibration schedule.

7.4 processing of the results

7.4.1 Mass fraction of copper , %, is calculated by the formula

, (3)

where is the mass concentration of copper in the sample solution found by the calibration schedule, g/cm;

mass concentration of copper in solution in the reference experiment, was found in the calibration schedule, g/cm;

 — the volume of the sample solution, cm;

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

7.4.2 discrepancies in the results must not exceed the values given in table 6.

Table 6

Percentage