GOST 6689.13-92

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  ГОСТ 6689.13-92

GOST 6689.13−92 Nickel, alloys Nickel and copper-Nickel. Methods for determination of arsenic

GOST 6689.13−92

Group B59

STATE STANDARD OF THE USSR

NICKEL, ALLOYS NICKEL AND COPPER-NICKEL

Methods for determination of arsenic

Nickel, nickel and copper-nickel alloys. Methods for the determination of arsenic

AXTU 1709

Date of introduction 1993−01−01

INFORMATION DATA

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

DEVELOPERS

V. N. Fedorov, Y. M. Leybov, Boris Krasnov, A. N. Bulanova, L. V. Morea, A. I. Vorobyov

2. APPROVED AND promulgated by the Decree of Committee of standardization and Metrology of the USSR from 18.02.92 N 167

4. REPLACE GOST 6689.13−80

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard establishes photometric methods for determination of arsenic (in mass fraction of arsenic from 0.0005 to 0.05%) and atomic absorption method for the determination of arsenic (in mass fraction from 0.005 to 0.05%) in Nickel, Nickel and copper-Nickel alloys according to GOST 492* and GOST 19241.
_________________
* On the territory of the Russian Federation GOST 492−2006. — Note the manufacturer’s database.

1. GENERAL REQUIREMENTS

General requirements for methods of analysis GOST 25086 with the addition of sec. 1 GOST 6689.1.

2. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF ARSENIC

2.1. The essence of the method

The method is based on formation of yellow michalopolous complex with subsequent restoration of its hydrazine sulfate to michalopolous blue. Method includes separation of arsenic from the basic components of alloys by coprecipitation with ferric hydroxide followed by extraction in the form of iodide of arsenic (III) carbon tetrachloride and Stripping it with water.

2.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

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

Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:3.

The mixture of acids to dissolve: concentrated nitric and hydrochloric acids in a ratio of 1:3.

Sulfuric acid according to GOST 4204, and diluted 1:4 and 3 mol/DMsolution.

Hydrofluoric acid according to GOST 10484.

Ammonia water according to GOST 3760 and diluted 1:50.

Hydrogen peroxide according to GOST 10929.

Potassium iodide according to GOST 4332, a solution of concentrated hydrochloric acid: 1 g of potassium iodide are dissolved in 60 cmof concentrated hydrochloric acid; prepared on the day of application.

Wash solution: three parts of a solution of potassium iodide is mixed with one part water.

The technical rectified ethyl alcohol according to GOST 18300.

Hydrazine sulfate according to GOST 5841 and a solution of 1.5 g/DM.

Ammonium molybdate according to GOST 3765, a solution of 10 g/DM3 mol/DMsolution of sulphuric acid; prepared from recrystallized drug. The recrystallization of ammonium molybdate is carried out according to GOST 6689.7.

The reaction mixture to 50 cmof a solution of ammonium molybdate add 5 cmof hydrazine sulfate solution and add water to volume of 100 cm; prepared on the day of application.

Alum salesonline for NTD, a solution of 100 g/DM.

10 g of alum was dissolved with heating in 70 cmwater and 5 cmof concentrated nitric acid, the solution filtered and diluted with water to 100 cm.

Potassium permanganate according to GOST 20490, a solution of 1 g/DM.

Silver nitrate according to GOST 1277, a solution of 10 g/DM.

Sodium hydroxide according to GOST 4328, solution 100 g/DM.

Phenolphthalein, solution at 10 g/lin ethanol.

Ammonium neccersarily according to GOST 20478.

Carbon tetrachloride according to GOST 20288.

Arsenious anhydride.

Standard solutions of arsenic.

Solution a: 0,132 g of arsenious anhydride is dissolved by heating in 10 cmof sodium hydroxide solution, transfer the solution into a volumetric flask with a capacity of 500 cm, neutralized to phenolphthalein with hydrochloric acid (1:3) and top up with water to the mark.

1 cmof the solution contains 0.0002 g of arsenic.

Solution B: 25 cmsolution And transferred to a volumetric flask with a capacity of 500 cmand topped to the mark with water.

1 cmof solution B contains 0,

00001 g of arsenic.

2.3. Analysis

2.3.1. For alloys containing less than 0.1% of silicon and chromium and tungsten

A portion of the alloy (see table.1) is placed in a beaker with a capacity of 250−300 cm, add 20−30 cmof nitric acid (1:1), cover with watch glass, glass or plastic plate and dissolved by heating. After dissolution of the sample watch glass or plate and the side of the Cup then rinsed with water, the solution diluted with water to 120−150 cm, add 1 cmof a solution of alum salesonline (when the mass fraction of iron in the alloy more than 0.1% salesonline alum is not added), heated to 60−70 °C and precipitated ferric hydroxide, carefully adding concentrated ammonia to the formation of soluble ammonia complexes of Nickel and copper and beyond that another 5−6 cmof excess ammonia.

Table 1

The solution was incubated for 30 min at 60−70 °C for coagulation of the precipitate of iron hydroxide. The precipitate was filtered off on a medium density filter, a glass and a precipitate was washed 6−8 times with a hot solution of ammonia (1:50), dissolved on the filter with 25 cm of hot sulphuric acid (1:4), collecting the solution in a glass, which conducted the deposition. Filter 5−7 times washed with hot water (if present in the alloy of manganese, by dissolving the precipitate in the beaker add a few drops of hydrogen peroxide). Deposition, filtering, washing and dissolution of the precipitate is carried out three times. The solution was boiled down until a white smoke of sulfuric acid. After cooling, rinse walls of beaker with water and repeat the evaporation until a white smoke of sulfuric acid, then added to a glass of 0.2−0.3 g of hydrazine sulfate and heated for 5−10 min.

When the mass fraction of arsenic in the alloy is less than 0.005% residue after evaporation is dissolved in 15 cmof water, the solution placed in a separatory funnel with a capacity of 250−300 cmand rinse the wall of the Cup 5 cmof water.

When the mass fraction of arsenic in the alloy in excess of 0.005% in a glass add 35−40 cmof water, the solution is placed into volumetric flask (see table 1) and dilute to the mark with water. Aliquot part — 20 cmis placed in a separating funnel with a capacity of 250−300 cm, add 60 cmof a solution of potassium iodide, 30 cmof carbon tetrachloride and extracted arsenic for 2 min. the Organic layer placed in a second separatory funnel with a capacity of 100−150 cm, and in the first add 15 cmof carbon tetrachloride and repeat the extraction again. The extracts are combined, washed for 2 min 20 cmwash solution and placed the organic layer into a third separating funnel with a capacity of 100−150 cm, it added 15 cmof water and carry out the Stripping of arsenic for 2 min.

The organic layer is poured into the fourth separating funnel with a capacity of 100−150 cmand repeat the Stripping under the same conditions. Water reextract placed in a volumetric flask with a capacity of 50 cm, is added dropwise a solution of potassium permanganate until a stable pink colour, which is destroyed, by adding dropwise a solution of hydrazine sulfate. Add 4 cmof the reaction mixture and the flask with the solution was placed in a boiling water bath. After 10−15 min, the solution was cooled, made up to the mark with water and measure the optical density of the solution on a photoelectrocolorimeter with a red light filter in a cuvette with a thickness of the light absorbing layer 1 see Solution comparison is the solution of the control

wow experience.

2.3.2. For alloys with a mass fraction of silicon than 0.1%

A portion of the alloy (see table.1) is placed in a platinum Cup, add 20−25 cmof nitric acid (1:1), 1−3 cmhydrofluoric acid and dissolved by heating. After cooling the walls of the Cup and rinse with water, add 5 cmof concentrated sulfuric acid and the solution is evaporated prior to the allocation of white smoke of sulfuric acid. A Cup of cool; rinse the walls with water and repeat the evaporation to start the selection of a white smoke of sulfuric acid. After cooling, the residue was dissolved with heating to 35−40 cmof water, were placed in a glass with a capacity of 250 cm, dilute with water to 120−150 cm, heated to 60−70 °C and precipitated ferric hydroxide, carefully adding ammonia to the formation of soluble ammonia complexes of Nickel and copper and beyond that another 5−6 cmof excess ammonia.

Further analysis are as indicated in claim 2.3.1

.

2.3.3. For alloys containing chromium

A portion of the alloy (see table.1) is placed in a platinum Cup, add 20−25 cmof nitric acid (1:1), 1−2 cmhydrofluoric acid and dissolved by heating.

After cooling the walls of the Cup and rinse with water, add 10 cmof concentrated sulfuric acid and the solution is evaporated prior to the allocation of white smoke of sulfuric acid. The Cup is cooled, rinse the wall with water and repeat the evaporation to start the selection of a white smoke of sulfuric acid. After cooling, the residue was dissolved with heating to 35−40 cmof water, the solution is placed in a beaker with a capacity of 300−400 cmand dilute with water to 200 cm, was added to a solution of silver nitrate: 15 cm — when mounting alloy 2 g, 8 cmat the sample of 1 g and 4 cm — for hanging of 0.5 g Administered 5 g naternicola ammonium (oxidation of chromium), the solution heated to boiling and boiled until the complete decomposition of ammonium naternicola (to complete the termination of allocation of bubbles of oxygen). The solution was cooled to 60−70 °C, rinse walls of beaker with water, add 1 cmof solution gentoomaniac alum and precipitated ferric hydroxide, carefully adding concentrated ammonia to the formation of soluble ammonia complexes of Nickel and copper over 5−6 cmof ammonia in excess. Further analysis are as indicated in claim 2

.3.1.

2.3.4. For alloys containing tungsten

A portion of the alloy (see table.1) is placed in a beaker with a capacity of 250 cm, 60−80 cm, addthe mixture of acids to dissolve and dissolve when heated. To the solution was added 5 cmof concentrated sulfuric acid and was boiled down to 10−12 cm. The solution is diluted with 30 cmof water and the precipitate tungsten acid is filtered off on a double thick filter. The beaker and precipitate was washed 5−6 times with hot hydrochloric acid (1:1). The precipitate with the filter thrown away, and to the filtrate is added 1 cmgentoomaniac alum solution, heated to 60−70 °C and precipitated ferric hydroxide, carefully adding ammonia to the formation of soluble ammonia complexes of Nickel and copper over 5−6 cmof excess ammonia. Further analysis are as indicated in claim 2.3.1

.

2.3.5. Construction of calibration curve

In glasses with a capacity of 250 cm, was placed 0,5; 1,0; 2,0; 3,0; 5,0; 6,0 cmstandard solution of arsenic add up to 10 cmof concentrated nitric acid and evaporated to dryness on a water bath.

The residue is dissolved in water, the solution diluted with water to 120−150 cm, add 1 cmgentoomaniac alum solution, heated to 60−70 °C and precipitated ferric hydroxide with ammonia. Further analysis are as indicated in claim 2.3.1 when the mass fraction of arsenic, less than 0.005%.

2.4. Processing of the results

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

,

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

 — the weight of the portion of alloy, suitable aliquote part of the solution,

2.4.2. Discrepancies in the results of three parallel measurements (rate of convergence) and the results of the two tests (index of reproducibility) shall not exceed the values of permissible differences given in table.2.

Table 2

2.4.3. Control of accuracy of analysis results is carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) of Nickel, Nickel or copper-Nickel alloys, approved under GOST 8.315*, or by a method of additives, or a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.
________________
* On the territory of the Russian Federation GOST 8.315−97. Here and further. — Note the manufacturer’s database.

3. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF ARSENIC

3.1. The essence of the method

The method is based on formation of yellow michalopolous complex with subsequent restoration of its sulphate with hydrazine in acidic solution to blue michalopolous. Previously arsenic from the basic components of alloys separated by coprecipitation with ferric hydroxide, followed by separation by distillation of arsenic trichloride arsenic from hydrochloric acid solution.

3.2. Apparatus reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

Apparatus for distillation of arsenic according to claim 3.3.1 or other device of a similar type.

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

Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:3.

The mixture of acids to dissolve one part of concentrated nitric acid mixed with three parts of concentrated hydrochloric acid.

Sulfuric acid according to GOST 4204, and diluted 1:4, 1:5 and 3 mol/DM.

Hydrofluoric acid according to GOST 10484.

Ammonia water according to GOST 3760 and diluted 1:50.

Hydrogen peroxide according to GOST 10929.

Rectified ethyl alcohol according to GOST 18300.

Hydrazine sulfate according to GOST 5841 and a solution of 1 g/DM.

Potassium bromide crystal according to GOST 4160.

Ammonium molybdate according to GOST 3765, a solution of 10 g/DM3 mol/DMsulfuric acid solution: prepared from recrystallized drug. The recrystallization of ammonium molybdate is carried out according to GOST 6689.7.

The freshly prepared reaction mixture: 50 cmof molybdate ammonium solution diluted with water to 150 cm, add 50 cmof hydrazine sulfate solution and add water to 500 cm.

Alum salesonline for NTD, a solution of 100 g/DM(preparation according to claim 2.2).

Silver nitrate according to GOST 1277, a solution of 10 g/DM.

Sodium hydroxide according to GOST 4328, solution 100 g/DM.

Phenolphthalein, solution at 10 g/lin ethanol.

Ammonium neccersarily according to GOST 20478.

Arsenious anhydride.

Standard solutions of arsenic (trade p

.2.2).

3.3. Analysis

3.3.1. A portion of the alloy (see table.1) dissolve and release arsenic by coprecipitation with ferric hydroxide, as described in Chapter 2.3.1. The residue after evaporation twice to release white smoke of sulfuric acid is cooled and carefully dissolved in 20 cmof water.

In the distillation flask 1 of the apparatus (the drawing) is placed 2 g of hydrazine sulfate and 1 g of potassium bromide, the receivers 5 and 7 pour 25−30 cmand 10−15 cmof water, respectively, added to each receiver 1−2 drops of hydrogen peroxide and harvested in accordance with the drawing.

1 — boiling flask; 2 — dropping funnel; 3 — tube with water seal; 4 — refrigerator; 5 — receiver; 6 — seal; 7 — control receiver

Analyze the solution through the drip funnel 2 placed in the distillation flask 1. The glass is rinsed with concentrated hydrochloric acid and the solution is transferred through the hopper 2 into flask 1. Into the flask 1 through the funnel 2 add 50 cmof concentrated hydrochloric acid and distilled arsenic trichloride when heated. Distilled to the original volume of the solution in the flask 1 with a uniform boiling (to ensure uniform boiling in the flask 1is placed a few glass beads).

After distilling off destillat of the receivers 5 and 7 are combined in dependence on the mass fraction of arsenic in the alloy in a glass with a capacity of 100 cm, if arsenic, less than 0.005%, or in a volumetric flask (see table 1) if the arsenic of 0.005%.

In the flask and the solution topped to the mark with water and mix.

Depending on the mass fraction of arsenic to an entire solution or its aliquote part, selected according to the table.1 placed in a beaker with a capacity of 100 cm, add 5 cmof concentrated nitric acid and evaporated with moderate heat to dryness. A glass of dry residue is placed in drying Cabinet and left for 1 h at 130 °C.

To the cooled residue are added 35 cmof the reaction mixture, cover with a glass watch glass and heated in a water bath at 100 °C for 10 min. After cooling, the solution is transferred to a volumetric flask with a capacity of 50 cm, made up of the reaction mixture up to the mark and mix.

Measure the optical density of the solution at 750 or 660 nm on the spectrophotometer or photoelectrocolorimeter.

Solution comparison is the solution of the reference experiment

.

3.3.2. For alloys containing silicon

A portion of the alloy (see table.1) dissolved, as indicated in claim 2.3.2, emit arsenic by coprecipitation with ferric hydroxide and the precipitate is treated as described in section 2.3.1. The residue after evaporation twice until white smoke of sulfuric acid is cooled, carefully dissolved in a small amount of water and further analysis are as indicated in claim 3.3.1.

3.3.3. For alloys containing chromium

A portion of the alloy (see table.1) dissolved, as indicated in claim 2.3.3, and emit arsenic by coprecipitation with ferric hydroxide, as described in Chapter 2.3.1. The residue after evaporation twice with sulfuric acid is cooled and carefully dissolved in a small amount of water. Further analysis are as indicated in claim 3.3.1.

3.3.4. For alloys containing tungsten

A portion of the alloy (see table.1) dissolved, separated the tungsten, as indicated in claim 2.3.4, and produce arsenic by coprecipitation with ferric hydroxide, as described in Chapter 2.3.1.

The residue after evaporation twice with sulfuric acid is cooled and carefully dissolved in a small amount of water. Further analysis are as indicated in claim 3.3.1.

3.3.5. Construction of calibration curve

In glasses with a capacity of 100 cmplaced 0; 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 and 6.0 cmto the standard solution of arsenic. In all the cups add 5 cmof concentrated nitric acid and evaporate the solutions to dryness on a water bath. Glasses with a dry residue is placed in drying Cabinet and left for 1 h at 130 °C and further analysis are as indicated in claim 3.3.1, for alloys with a mass fraction of arsenic, less than 0.005%. Solution comparison is the solution not containing arsenic.

3.4. Processing of the results

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

,

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

 — weight of alloy, suitable aliquote part of the solution,

3.4.2. The discrepancy between the results of three parallel measurements (rate of convergence) and the results of the two tests (index of reproducibility) shall not exceed the values of permissible differences given in table.2.

3.4.3. Control of accuracy of analysis results is carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) of Nickel, Nickel and copper-Nickel alloys, approved under GOST 8.315, or the comparison with results obtained by atomic absorption method, in accordance with GOST 25086.

4. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF ARSENIC

4.1. The essence of the method

The method is based on dissolving the samples in acids, separation of arsenic by coprecipitation with ferric hydroxide, dissolving the precipitate in hydrochloric acid and measuring the atomic absorption of arsenic in the flame acetylene-air or acetylene-nitrous oxide at a wavelength of 193.7 nm.

4.2. Apparatus, reagents and solutions

Atomic absorption spectrometer with a radiation source for arsenic.

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

Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:5.

A mixture of acid: mix one volume of nitric acid with three volumes of hydrochloric acid.

Hydrofluoric acid according to GOST 10484.

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

Ammonia water according to GOST 3760 and diluted 1:99.

Hydrogen peroxide according to GOST 10929.

Sodium hydroxide according to GOST 4328, solution 80 g/lfreshly prepared.

Iron, the reduced hydrogen.

Ferric chloride, solution: 0.75 g of iron dissolved in 20 cmof hydrochloric acid with addition of hydrogen peroxide solution, the solution transferred to a volumetric flask with a capacity of 250 cm, and topped to the mark with water.

1 cmof the solution contains 0.003 g of iron.

Arsenious anhydride.

Standard solution of arsenic: 1.3200 levels g of arsenious anhydride are dissolved in 20 cmof sodium hydroxide solution, add 10 cmwater, 10 cmof hydrochloric acid solution (1:5), transferred to a volumetric flask with a capacity of 1 DMand topped to the mark with water.

1 cmof the solution contains 0.001 g mouse

ka.

4.3. Analysis

4.3.1. For alloys containing silicon, not more than 0.05%

A sample of alloy weighing 5 g were placed in a glass with a capacity of 400 cmand dissolved by heating at 40 cmof a mixture of acids. The solution is diluted with water to a volume of 200 cm, add 10 cmof a solution of ferric chloride, heated to 70 °C, and carefully neutralized with ammonia before the formation of soluble ammonia complexes of Nickel and copper and add another 5 cmin excess. The solution was heated and leave in a warm place for 30 minutes, then filtered through a filter of medium density. The filter cake is washed three times with hot ammonia solution (1:99), then twice with hot water. The precipitate is dissolved in 10 cmof hot hydrochloric acid (1:1), collecting the solution in a glass, which conducted the deposition. The solution was transferred to a volumetric flask with a capacity of 25 cmand top up with water to the mark. At the same time spend control experience.

Measure the atomic absorption of arsenic in the flame of acetylene-air and acetylene-nitrous oxide parallel to the calibration solutions at a wavelength of 193.7 nm

.

4.3.2. For alloys containing silicon in excess of 0.05%

A portion of the sample weighing 5 g was placed in a platinum Cup and dissolved by heating in 30 cmof nitric acid (1:1) and 5 cmhydrofluoric acid. Then add 10 cmsulphuric acid (1:1) and evaporated until a white smoke of sulfuric acid. The Cup is cooled, add 50 cmof water and boil to dissolve the salts. The solution was transferred to a beaker with a capacity of 400 cm, add 10 cmof a solution of ferric chloride and then act as described in section 4.3.1.

4.3.3. Construction of calibration curve

In six of the seven volumetric flasks with a capacity of 100 cmis placed 0,5; 1,0; 2,5; 5,0; 7,5 and 10,0 cmstandard solution of arsenic, which corresponds to 0,5; 1,0; 2,5; 5,0; 7,5 and 10,0 mg of arsenic, made up to the mark with hydrochloric acid (1:5). Measure the atomic absorption of arsenic, as specified in clause 4.3.1. According to the obtained results build a calibration curve.

4.4. Processing of the results

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

,

where is the concentration of arsenic in the analyzed solution alloy, was found in the calibration schedule, g/cm;

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

 — the volume of the sample solution, cm;

 — weight of sample, g

.

4.4.2. Discrepancies in the results of three parallel measurements (rate of convergence) and the results of the two tests (index of reproducibility) shall not exceed the values of permissible differences given in table.2.

4.4.3. Control of accuracy of analysis results is carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) of Nickel, Nickel or copper-Nickel alloys, approved under GOST 8.315, or by additives or by comparison of the results obtained photometric methods in accordance with GOST 25086.