GOST 13938.6-78

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  ГОСТ 13938.6-78

GOST 13938.6−78 Copper. Methods for determination of Nickel (amended N 1−5)

GOST 13938.6−78

Group B59

INTERSTATE STANDARD

COPPER
Methods for determination of Nickel
Copper.
Methods for determination of nickel

AXTU 1709

Date of introduction 1979−01−01

INFORMATION DATA

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

DEVELOPERS

G. P. Giganov, E. M. Peneva, A. A. Blyahman, E. D. Shuvalov, A. N. Savelieva

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 24.01.78 N 155

3. REPLACE GOST 13938.6−68

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)

6. REPRINT (November 1999), with Changes N 1, 2, 3, 4, 5, approved in March 1979, April 1983, June 1985, April 1988, November 1990 (IUS 5−79, 7−83, 8−85, 7−88, 2−91)


This standard sets the photometric and atomic absorption (at a mass fraction of from 0.0005 to 0.5%) methods for determination of Nickel in copper grades according to GOST 859*.

________________

* Here and further. Valid GOST 859−2001. — Note the CODE.

(Changed edition, Rev. N 4, 5).

1. GENERAL REQUIREMENTS

General requirements for methods of analysis and safety requirements when performing tests according to GOST 13938.1.

Sec. 1. (Changed edition, Rev. N 4).

2. The PHOTOMETRIC METHOD for the DETERMINATION of NICKEL (at a mass fraction of Nickel from 0.0005 to 0.5%)

2.1. The essence of the method

The method is based on formation of colored compounds of Nickel with dimethylglyoxime in the environment of ammonia or sodium hydroxide, after separation of Nickel in the form of dimethylglyoximate by extraction with chloroform and Stripping of Nickel with hydrochloric acid. Optical density of the solution is measured at a wavelength of 434−450 nm. Copper is associated with sodium thiosulfate to a colorless complex at a pH of 6.2 to 6.8.

(Changed edition, Rev. N 4, 5).

2.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer with all accessories.

pH meter with all accessories.

Nitric acid according to GOST 4461, diluted 1:1 and 3:2.

Hydrochloric acid according to GOST 3118, 0.5 N. the solution and dilute 1:3.

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

Acetic acid according to GOST 61.

Tartaric acid (tartaric acid) according to GOST 5817.

Ammonia water according to GOST 3760, diluted 1:1 and 1:49.

Bromine according to GOST 4109, saturated aqueous solution (bromine water).

Dimethylglyoxime according to GOST 5828, alcohol and a freshly prepared solution of 5 g/DMand a solution of 10 g/DMsolution of sodium hydroxide 80 g/DM.

Sodium hydroxide according to GOST 4328, solutions 80, 100, and 400 g/DM.

The anhydrous sodium carbonate according to GOST 83, a solution of 500 g/DMand a solution of 10 g/lin sodium hydroxide solution with the mass concentration of 400 g/DM.

Chernovetskiy sodium (sodium thiosulfate) 5-water according to GOST 27068, 50% solution

Sodium acetate according to GOST 199.

Acetate buffer solution; prepared as follows: 300 g of sodium acetate dissolved in 500 cmof water and set pH (6,5±0,3) by the addition of acetic acid. The solution was transferred to volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

Tartrate buffer solution; prepared as follows: 150 g of tartaric acid dissolved in 500 cmof water and set pH (6,5±0,3) addition of a solution of 400 g/DMsodium hydroxide. The solution was transferred to volumetric flask with a capacity of 1 DM, add water and mix.

Rectified ethyl alcohol according to GOST 18300.

Chloroform according to GOST 20015.

Iodine GOST 4159, alcoholic solution of 10 g/DM (3).

Nickel GOST 849.

Nickel sulfate according to GOST 4465.

Solutions of Nickel standard.

Solution A, prepared as follows: 4,784 g of Nickel sulfate were placed in a glass with a capacity of 250 cm, add 50 cmof water, 1 cmof sulfuric acid, transferred into a volumetric flask with a capacity of 1 DM, made up to the mark and mix.

When using metallic Nickel 1,000 g of Nickel when heated, dissolved in 50 cmof hydrochloric acid and 20 cmof hydrogen peroxide, the solution was cooled, poured 10 cmof sulphuric acid diluted 1:1, and the solution was evaporated until the appearance of sulphuric acid fumes. The residue is cooled, poured 100 cmof water, transfer the solution into a measuring flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 1 mg of Nickel. The same solution can be prepared as follows: a portion of the Nickel mass of 1.0 g was dissolved with heating in 20−25 cmof nitric acid, diluted 3:2, and the solution is evaporated to a volume of 3−5 cm. Then add 20 cmof sulphuric acid diluted 1:1, and evaporated to release vapors of sulfuric acid. After cooling, pour 100−150 cmof water, dissolve the salt and transfer the solution into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water.

Solution B is prepared as follows: 100 cmof solution A is placed in a volumetric flask with a capacity of 1 DM, added 1 cmof sulfuric acid diluted 1:1, made up to the mark with water and mix.

1 cmof a solution contains 0.1 mg of Nickel.

Solution; prepared as follows: 25 cmof a solution is placed in a volumetric flask with a capacity of 250 cm, is diluted to the mark with water and mix.

1 cmof the solution contains 0.01 mg of Nickel.

Solutions B and C using freshly prepared.

Hydrogen peroxide (perhydrol) according to GOST 10929.

Copper according to GOST 859 (mass fraction of Nickel is less than 0,0005%).

Solutions of copper.

Solution A, prepared as follows: 25.0 g of copper is dissolved in 200 cmof nitric acid, diluted 1:1, the solution is heated to remove oxides of nitrogen, cooled and transferred to volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.1 g of copper.

Solution B is prepared as follows: 25 cmsolution And placed in a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of copper. The solution is stable for 8 hours

Potassium-sodium vinocity (Sagatova salt) according to GOST 5845, a solution of 200 g/DM.

Ammonium neccersarily according to GOST 20478, a solution of 30 g/DM. Allowed the use of other reagents, subject to obtaining the metrological characteristics are not inferior to those specified in the standard.

A mixture of hydrochloric and nitric acids in the ratio 3:1, using freshly.

Citric acid, a solution of 100 g/DM.

(Changed edition, Rev. N 2, 4, 5).

2.3. Analysis

2.3.1. Determination of Nickel in its mass fraction from 0.0005 to 0.005%

A sample of copper with a mass of 1.0 g was placed in a beaker with a capacity of 250 cmand add 10 cmof nitric acid, diluted 1:1. After the cessation of violent reaction solution is gently boiled to remove oxides of nitrogen (7−10 min), evaporated to approximately 3 cm, to the solution was added 10 cmof water and heated to boiling. The solution is cooled, add ammonia solution, diluted 1:1, before the appearance of the precipitate of the hydroxide, and then dropwise hydrochloric acid diluted 1:3, to dissolve the residue. To a solution pour 3 cmtartrate buffer solution, a 3 cmacetate buffer solution and 25 cmof a solution of sodium servational. The pH value of the solution (6,5±0,3) control with the help of pH meter. The solution was transferred to a separatory funnel with a capacity of 100 cm, 2 cm, pour thealcohol solution dimethylglyoxime, mixed and solution incubated for 1−2 min.

Content funnel add 5 cm(for analysis according to claim 2.3.1) of chloroform or 10 cm(for analysis according to claim 2.3.1 a) and extracted the compound of Nickel for 1 min, the Chloroform extract separated and placed in another separatory funnel. To the aqueous solution in the funnel add another 5 cm(for analysis according to claim 2.3.1) or 10 cm(for analysis according to claim 2.3.1 a) of chloroform and repeat the extraction. Drain the extracts into the glass, which carried out the decomposition of the sample, the ammonia solutions are discarded. The chloroform extract is attached to the combined chloroform extract.

To the combined chloroform extracts add 5 cm(for analysis according to claim 2.3.1) or 10 cm(for analysis according to claim 2.3.1 a) 0.5 mol/DMhydrochloric acid solution and extragent Nickel for 1 min, the chloroform is drained into another separating funnel and repeat two more times. Extracts were placed in a glass with a capacity of 100 cm.

When working in the environment of ammonia reextract collected in a beaker with a capacity of 100 cm, heated to boiling and evaporated to a volume of 7−10 cm, cooled, placed in a volumetric flask with a capacity of 25 or 50 cmand consistently pour 2 cmof the alcoholic solution dimethylglyoxime, 5 cmsolution naternicola ammonium and 5 or 10 cmof ammonia, diluted 1:1.

When working in the environment of sodium hydroxide reextract placed in a beaker with a capacity of 100 cmand successively added 1 cmof the citric acid solution, 2 cmof a solution of ammonium naternicola 10 cmof sodium hydroxide solution (80 g/DM) and 1 cmof solution dimethylglyoxime in sodium hydroxide solution. The solution is heated to 60 °C and left at this temperature for 5 min. Then cooled, placed in a volumetric flask with a capacity of 50 cm, is diluted to the mark with water and mix. Optical density of the solution measured as described above.

Mass of Nickel is determined according to the calibration schedule, constructed as described in section 2.4.1.

At the same time carried out two test experience, performing the same operations and Prilepa the same reagents as in the analysis of the sample. The average optical density of the solution in the reference experiment is subtracted from the value of the optical density of the analyzed solution.

(Changed edition, Rev. N 4, 5).

2.3.1. For copper-containing sparingly soluble Nickel compounds, the dissection of the sample is performed as follows: a sample of copper with a mass of 1.0 g was placed in a beaker with a capacity of 250 cm, flow 20 cmof a mixture of hydrochloric and nitric acids, and evaporated when heated to wet salts. Then add 10 cmof hydrochloric acid and evaporated to dryness. This operation is repeated two more times. After cooling, the dry residue moistened with 3 cmof hydrochloric acid, poured 10 cmof water and heated to dissolve the salts. The solution is cooled, add the ammonia, diluted 1:1, before the appearance of the precipitate of hydroxides and then dropwise a solution of hydrochloric acid 0.5 mol/lto dissolve the residue. To the obtained solution pour 3 cmtartrate buffer solution and 3−5 cmacetate buffer solution to dissolve the residue. Add 35 cmof sodium thiosulfate and then dropwise until discoloration of the solution (until the full restoration of copper). Then continue according to claim 2.3.1.

(Added, Rev. N 5).

2.3.2. Determination of Nickel in its mass fraction from 0.005 to 0.05%

A sample of copper with a mass of 1.0 g was placed in a beaker with a capacity of 250 cmand go on as shown in step 2.3.1.

For the extraction of Nickel compounds is used twice in 10 cmof chloroform, and then carry out the analysis as described in section 2.3.1.

From the combined chloroform extracts twice extragere Nickel 0,5 g/DMhydrochloric acid solution, using each time 10 cmof the acid and shaking the contents of the funnel for 1 min. Hydrochloric acid, the solutions were poured into a glass with a capacity of 50 cm, heated to boiling, cooled and poured into a volumetric flask with a capacity of 100 cm. Add successively 2 cmof bromine water and 2 cm, oralcoholic iodine solution, 2 cmof mortar dimethylglyoxime and 20 cmof sodium carbonate solution, poured the solution to the mark with water and mix. After 10 minutes measure the optical density of the solution at a wavelength of 450 nm in a cuvette with an optimum thickness of the layer.

Solution comparison when measuring optical density of the solution is water.

At the same time carried out two test experience as described in claim 2.3.1. Extraction, Stripping and measurement of the optical density of the solution perform as specified above. The average optical density of the solution in the reference experiment is subtracted from the value of the optical density of the analyzed solution.

Mass of Nickel is determined according to the calibration schedule, constructed as described in section 2.4.2.

2.3.3. Determination of Nickel in its mass fraction from 0.05 to 0.5%

A sample of copper with a mass of 1.0 g is dissolved and removed as specified in claim 2.3.1.

The cooled solution was transferred to volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. 10 cmof the solution was transferred by pipette into a glass with a capacity of 100 cm, add ammonia solution, diluted 1:1, before the appearance of the precipitate of the hydroxide, and then dropwise hydrochloric acid diluted 1:3, to dissolve the residue. To a solution pour 3 cmtartrate buffer solution, a 3 cmacetate buffer solution, 2.5 cmchernovetskogo sodium, mix and set pH (6,5±0,3). The solution was transferred to a separatory funnel with a capacity of 100 cmand then carry out the analysis as described in section 2.3.2.

At the same time carried out two test experience. To do this in a glass with a capacity of 100 cmplaced 1 cmnitric acid, diluted 1:1, and evaporated to dryness. To the residue is added 1 cmto 0.5 g/DMhydrochloric acid solution, 3 cmtartrate buffer solution, a 3 cmacetate buffer solution, 2.5 cmchernovetskogo sodium, mix and set pH (6,5±0,3). The solution was transferred to a separatory funnel with a capacity of 100 cmand further analysis is carried out as specified in clause 2.3.2.

The average optical density of the solution in the reference experiment is subtracted from the value of the optical density of the analyzed solution.

A lot of Nickel sets for the calibration graphics constructed as described in section 2.4.3.

(Changed edition, Rev. N 4).

2.4. Construction of calibration curve

2.4.1. Construction of calibration curve in mass fraction of Nickel from 0.0005 to 0.005%

In glasses with a capacity of 100 cmtaken at 10 cmof a solution of copper and 0; 0,5; 1,0; 2,0; 3,0; 4,0 and 5.0 cmof a standard solution of Nickel, which corresponds to 0; 5; 10; 20; 30; 40 and 50 µg of Nickel. The control experiment is the copper solution without the addition of a standard solution of Nickel. The solutions were evaporated to about 3 cm. The residue is dissolved in 10 cmof water and then do as stated in claim 2.3.1 or 2.3.1.

(Changed edition, Rev. N 5).

2.4.2. Construction of calibration curve in mass fraction of Nickel from 0.005 to 0.05%

In glasses with a capacity of 100 cmtaken at 10 cmof a solution of copper and 0; 0,5; 1,0; 2,0; 3,0; 4,0 and 5.0 cmstandard solution B, which corresponds to 0; 50; 100; 200; 300; 400 and 500 micrograms of Nickel. The control experiment is the copper solution without the addition of a standard solution of Nickel. The solutions were evaporated to about 3 cm, the residue is dissolved in 10 cmof water, transfer the solution in a separating funnel with a capacity of 100 cmand then carry out analysis as specified in claim 2.3.2.

2.4.3. Construction of calibration curve in mass fraction of Nickel from 0.05 to 0.5%

In glasses with a capacity of 100 cmtaken at 10 cmof copper solution Used and 0; 0,5; 1,0; 2,0; 3,0; 4,0 and 5.0 cmstandard solution B of Nickel, which corresponds to 0; 50; 100; 200; 300; 400 and 500 micrograms of Nickel. The control experiment is the copper solution without the addition of a standard solution of Nickel. The solutions were evaporated to about 3 cm. The residue is dissolved in 10 cmof water, transfer the solution in a separating funnel with a capacity of 100 cmand then do the same as shown in clause 2.3.3.

The values of optical density of solutions found in the PP.2.4.1−2.4.3, and their respective contents of Nickel built calibration graphs.

(Changed edition, Rev. N 2, 4).

2.4.4. Allowed the use of the electrolyte after separation of the copper in accordance with GOST 13938.1.

In the electrolyte add 5 cmof sulfuric acid solution (1:1) and evaporated to release vapors of sulfuric acid, cooled, poured 5−10 cmof water and the evaporation repeated.

To the cooled residue poured 30−50 cmof water, boil for 5−7 minutes, cool, and if the insoluble residue is filtered on a dense filter in the cone which is enclosed a little filtrowanie mass, collecting the filtrate in a volumetric flask with a capacity of 100, 200, or 500 cmdepending on the mass fraction of Nickel. The residue on the filter is washed 4−5 times with water and the filter discarded. The filtrate in a volumetric flask diluted to the mark with water and mix.

Aliquot part containing Nickel in the range of 0.005−0.05 mg, is placed in a volumetric flask with a capacity of 50 cm; pour 2.5 cmof a solution of Rochelle salt, 7.5 cmof sodium hydroxide solution (100 g/DM) 10 cmsolution of ammonium naternicola and 10 cmin the sodium hydroxide solution dimethylglyoxime, then dilute to the mark with water and mix. After 10−20 min, measure the optical density of the solution, as mentioned in paragraph 2.3.1.

Mass of Nickel is determined according to the calibration schedule.

To build a calibration curve in five out of six volumetric flasks with a capacity of 50 cmplaced respectively 0,5; 1,0; 2,0; 4,0; 5,0 and 10 cmstandard solution B or C and then continue the analysis as described above. According to the obtained values of optical densities and their corresponding concentrations build schedule.

(Changed edition, Rev. N 4, 5).

3. ATOMIC ABSORPTION METHOD for the DETERMINATION of NICKEL (at a mass fraction of Nickel from 0.002 to 0.4% and from 0.0005 to 0.004%)

3.1. The essence of the method

The method is based on measuring the atomic absorption of the resonance lines of Nickel in the introduction of the analyzed solution in the flame acetylene-air or propane-butane-air. When the content of Nickel 0.004% conducted pre-concentration by extraction with chloroform complex of Nickel with dimethylglyoxime.

(Changed edition, Rev. N 5).

3.2. Apparatus, reagents and solutions

Spectrophotometer, atomic absorption, comprising a lamp with a Nickel hollow cathode, the burner for flame and a spray system.

Acetylene according to GOST 5457 or propane-butane according to GOST 20448.

Air compressor.

Distilled water according to GOST 6709.

Nitric acid according to GOST 4461, diluted 1:1 and 3:2.

Hydrochloric acid according to GOST 3118.

Copper, standard sample for spectral analysis N 312 containing 2·10% Nickel or electrolytic copper with the established content of Nickel, the copper solution of 100 g/DM. 10 g of a standard sample of copper is placed in a conical flask with a capacity of 250 cmand dissolved by heating to 70 cmof nitric acid, diluted 1:1. The solution is evaporated to remove the bulk of the acid, cooled and transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

10 cmof copper solution containing 2 µg of Nickel.

Nickel GOST 849.

Solutions of Nickel standard.

Solution A, prepared as follows: 0,100 g of Nickel dissolved in 10 cmof nitric acid, diluted 3:2, the solution was transferred to volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 0.1 mg of Nickel.

Solution B is prepared as follows: 10 cmof solution A is placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 mg of Nickel.

(Changed edition, Rev. N 4, 5).

3.3. Analysis

3.3.1. A sample of copper with a mass of 1.0 g was placed in a conical flask with a capacity of 100 cmand dissolved by heating in 10 cmof nitric acid, diluted 1:1. If, after the dissolution of the copper precipitate remains insoluble black color, solution pour 1−2 cmof hydrochloric acid and the solution is evaporated to wet salts. The contents of the flask cool, add 10 cmof water and heated to dissolve the salts. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. The resulting copper solution sprayed in the flame acetylene-air or propane-butane-air atomic absorption spectrophotometer and measure the absorbance in the flame at a wavelength 323,0 or 232,0 nm.

At the same time conducting follow-up experience with all the applied reagents. The value of the optical density of the solution in the reference experiment is subtracted from the value of the optical density of the analyzed solution.

The mass of Nickel in the solution is determined by the calibration graphs.

Allowed to determine the mass fraction of Nickel using addition method.

(Changed edition, Rev. N 2, 5).

3.3.2. Construction of calibration graphs

3.3.2.1. Construction of calibration curve for the mass concentration of Nickel from 0.002 to 0.05%

In a volumetric flask with a capacity of 100 cmpour 0, 1, 2, 5, 8, 10, 20 and 50 cmstandard solution B, 10 cmof copper solution, made up to the mark with water and mix measure the absorbance at the wavelength of 232,0 nm.

The resulting solutions contain 2, 12, 22, 52, 82, 102, 202 and 502 µg of Nickel.

(Changed edition, Rev. N 2, 5).

3.3.2.2. Construction of calibration curve in mass fraction of Nickel from 0.05 to 0.4%

In a volumetric flask with a capacity of 100 cmis placed 2, 5, 10, 20 and 40 cmof solution A, which corresponds to 0,2; 0,5; 1,0; 2,0 and 4,0 mg of Nickel, the solution is topped up to the mark with water and mix.

Measure the absorption at a wavelength 323,3 nm.

According to the obtained values of optical density of solutions and the corresponding content of the Nickel to build the calibration graphs.

(Changed edition, Rev. N 5)

3.4. In the determination of Nickel with a mass fraction of from 0.0005 to 0.004% dissolution of sample, separation of Nickel extraction and Stripping is carried out in accordance with paragraph 2.3.1 or 2.3.1.

Reextract placed in a volumetric flask with a capacity of 25 cm, is diluted to the mark with water and mix. Measure the absorption line of Nickel at a wavelength of 232 nm simultaneously with solutions of control experience and solutions to build the calibration curve.

To build a calibration curve of six tumblers with a capacity of 250 cmis placed 1.0 g of copper standard sample and then continue the dissolution, as mentioned in paragraph 2.3.1. Then, in five of the six cups are placed 0,5; 1,0; 2,0; 3,0 and 4,0 cmstandard solution B, and then continue the analysis as described in section 2.3.1 or 2.3.1.

Measure the absorption line of Nickel at a wavelength of 232,0 nm and the data obtained are building gradirovskiy schedule.

It allowed the determination in the analyzed solution of zinc (from 0.0005 to 0,006%), iron (0.01 to 0.06%), lead (from 0.005 to 0.06%) and cobalt (0.005 to 0.06%).

Allowed the use of the electrolyte after separation of copper GOST 13938.1. For this part of the electrolyte (depending on the mass fraction of Nickel) was placed in a beaker (or flask) capacity of 100 cmand spray the solution into the flame of acetylene-air or propane-butane-air at wavelengths 232,0; 352,4 nm depending on the concentration of Nickel in the analyzed solution.

(Changed edition, Rev. N 4, 5).

4. PROCESSING OF THE RESULTS

4.1. Mass fraction of Nickel (), in per cent by photometric determination calculated by the formulas:

when the mass fraction of Nickel from 0.0005 to 0.05%

,

where is the mass of the copper sample, g;

 — the weight of a Nickel, was found in the calibration schedule, mcg;

when the mass fraction of Nickel from 0.05 to 0.4%

,

where is the mass of the copper sample, g;

 — the weight of a Nickel, was found in the calibration schedule, mcg;

 — the volume of the analyzed solution, cm;

 — volume aliquote part of the analyzed solution, cm.

4.2. Mass fraction of Nickel () in the percentage of atomic-absorption determination is calculated by the formula

,

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

 — weight of copper,

4.3. Discrepancies in the results of two parallel measurements and the two tests should not exceed the values given in the table.

(Changed edition, Rev. N 4).

4.4. The differences in the assessment of mass fraction of Nickel is used the photometric method.

(Changed edition, Rev. N 4, 5).

APP. (Deleted, Rev. N 4).