GOST 6689.3-92

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  ГОСТ 6689.3-92

GOST 6689.3−92 Nickel, alloys Nickel and copper-Nickel. The method of determining the amount of Nickel and cobalt

GOST 6689.3−92

Group B59

STATE STANDARD OF THE USSR

NICKEL, ALLOYS NICKEL AND COPPER-NICKEL

The method of determining the amount of Nickel and cobalt

Nickel, nickel and copper-nickel alloys. Method for the determination of nickel and cobalt sum

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, B. P. Krasnov, Y. M. Leybov, A. N. Baganova, N. Vorobyov

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

3. REPLACE GOST 6689.3−80

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies electrogravimetry method of determining the amount of Nickel and cobalt (with a mass fraction more than 0.5%) in Nickel and copper-Nickel alloys except alloy chromel according to GOST 492* and GOST 19241.
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* On the territory of the Russian Federation GOST 492−2006. — Note the manufacturer’s database.

The method is based on electrolytic deposition of Nickel and cobalt from ammoniacal medium in the presence of ammonium sulfate.

Allowed determination of total mass fraction of Nickel and cobalt by adding the results of separate determination of Nickel GOST 6689.2 and cobalt GOST 6689.9.

1. GENERAL REQUIREMENTS

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

2. EQUIPMENT, REAGENTS, SOLUTIONS

Electrolysis installation DC.

Platinum electrodes according to GOST 6563.

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

Sulfuric acid according to GOST 4204, diluted 1:1 and 1:4.

Hydrofluoric acid according to GOST 10484.

Hydrochloric acid according to GOST 3118 and a solution of 2 mol/DM.

A mixture of the acid freshly prepared by mixing three parts of concentrated hydrochloric acid with one part concentrated nitric acid.

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

Ammonium neccersarily according to GOST 20478, a solution of 200 g/DM.

Ammonium sulfate according to GOST 3769.

Hydrazine sulfate according to GOST 5841, a solution of 10 g/DM.

Dimethylglyoxime according to GOST 5828, alcoholic solution of 10 g/DM.

The technical rectified ethyl alcohol according to GOST 18300.

Sodium chloride according to GOST 4233, saturated solution.

Sodium hydroxide according to GOST 4328, solutions 50, 100 g/land 2 mol/DM.

Potassium rodanistye according to GOST 4139, a solution of 10 g/DM.

Silver nitrate according to GOST 1277, a solution of 5 g/DM.

Anion exchange resin AV-17, an-31 or EDE-10

P.

2.1. Preparation of chromatographic column

50 g of the anion exchanger was placed in a beaker with capacity of 500 cm, pour 400 cmof saturated sodium chloride solution and allowed to stand for 24 hours at room temperature. The solution is decanted and the resin was washed by decantation 2 mol/DMhydrochloric acid solution to remove iron ions (reaction with potassium thiocyanate).

The anion exchange resin sequentially was washed with sodium hydroxide solution 50 g/DM, then with a solution of 100 g/DMthe complete removal of chloride ions (reaction with silver nitrate). The anion exchanger is washed with water until a weakly alkaline reaction, then treated with three portions of 2 mol/DMof hydrochloric acid.

In the lower part of ion exchange columns is placed glass wool with a layer of 3−5 mm and fill the column with anion exchange resin to a height of 30−32 cm and is filled with 2 mol/DMhydrochloric acid, while carefully ensure that air bubbles did not stay between the grains of resin. Before passing the solution through the anion resin layer of hydrochloric acid over the resin should be 1 to 2 cm.

After chromatographic separation of the anion exchanger is regenerated by passing through a column of water to a slightly alkaline reaction of the wash water, then with 100 cmof 2 mol/DMof hydrochloric acid.

3. ANALYSIS

3.1. For alloys containing less than 0.05% of copper

3.1.1. For alloys containing less than 0.1% silicon

A portion of the alloy of 1 g was placed in a beaker with a capacity of 300 cm, add 15 cmof nitric acid (1:1), cover with watch glass, glass or plastic plate and dissolved by heating. After dissolution of the alloy watch glass or plate and the side of the Cup and rinse with water, add 10 cmsulphuric acid (1:1) and evaporated to copious fumes of sulfuric acid.

The residue is cooled and dissolved in 100 cmof water when heated.

For alloys containing manganese in excess of 1%, the solution was added 20 cmof a solution of ammonium naternicola. The solution is heated to boiling and slightly boiled for 15−20 min to complete the destruction of excess naternicola ammonium (until the termination of allocation of bubbles of oxygen).

To the cooled solution add the ammonia until the full transition of Nickel in a soluble ammonia complex. In case of allocation of hydroxide of aluminium, iron and manganese solution and the precipitate are heated to 60−70 °C and kept at this temperature for about 30 min. the Precipitate was filtered off on a medium density filter and wash the beaker and filter with the sediment 3−4 times a hot ammonia (1:50). The filtrate is saved. The precipitate is dissolved in 10 cmhot sulphuric acid (1:4). The filter carefully washed with hot water, collecting the solution and the washing water in the glass in which was conducted the deposition, and again precipitated by hydroxides of aluminium, iron and manganese with ammonia. The precipitate was filtered off on a medium density filter and thoroughly washed with hot ammonia solution (1:50) to a reaction to Nickel (reaction with dimethylglyoxime, see below). Both filtrate are combined and evaporated to a volume of 120 cm.

Ammonia solution or the filtrate is heated to 60−70 °C, add 25 cmof ammonia (1:1) and 3 g of ammonium sulfate.

Immerse electrodes into the solution and conduct electrolysis at a current of 2−3 A and stirring. A glass electrolyte serves the two halves hour glass, glass or plastic plate with holes for electrodes and stirrer. During electrolysis it is recommended to add to the electrolyte in small portions of 0.5−1.5 cmof a solution of hydrazine sulfate.

After the bleaching solution, the electrolysis is continued for 10 min and then control the fullness of the release of Nickel. To do this, in a porcelain Cup taken away a few drops of the electrolyte, add a few drops of solution dimethylglyoxime and heated to remove excess ammonia. If no red precipitate is formed or the solution becomes pink, then electrolysis is complete. Without turning off the current, the electrodes are rinsed with water and washed cathode sequentially in three beakers of water and then by turning off the current, the cathode was washed in a beaker with 200 cmof ethanol. One serving of alcohol may be used for washing no more than 20 electrodes. The cathode is dried at 105 °C to constant weight and vzvesi

ayut.

3.1.2. For alloys containing more than 0.1% silicon

A sample of alloy weighing 1 g is placed in a platinum Cup, add 10 cmof concentrated nitric acid, 2−3 cmhydrofluoric acid, cover made of platinum or PTFE and dissolved by heating. After dissolution of the alloy cover and the walls of the Cup and rinse with water, add 10 cmsulphuric acid (1:1) and evaporated until copious white smoke of sulfuric acid. The cooled residue is dissolved in 100 cmwater when it is heated, transferred to a beaker with a capacity of 300 cmand then do as described in claim 3.1.1.

3.2. For alloys containing more than 0.05% of copper

3.2.1. For alloys containing less than 0.1% silicon

A portion of the alloy weight 2 g for the mass concentration of the sum of Nickel and cobalt less than 10% and 1 g when the mass fraction of more than 10% were placed in a glass with a capacity of 300 cm, add 30 or 15 cmof nitric acid (1:1), covered with a glass watch glass, glass or plastic plate and dissolved by heating. After dissolution, the samples are rinsed watch glass or plate and the side of the Cup with water and boil the solution to remove oxides of nitrogen. The solution is diluted with water to 150 cm, add 7 cmof sulphuric acid (1:4) and produce copper by electrolysis according to GOST 6689.1.

In the electrolyte after separation of copper add 10 cmsulphuric acid (1:1) and evaporated until copious white smoke of sulfuric acid and then act as described in section 3.1.1.

3.2.2. For alloys containing more than 0.1% silicon

A sample of alloy weighing 1 g is placed in a platinum Cup, add 10 cmof concentrated nitric acid, 2−3 cmhydrofluoric acid, cover made of platinum or PTFE and dissolved by heating. After dissolution of the alloy cover and the walls of the Cup and rinse with water, add 10 cmsulphuric acid (1:1) and evaporated until copious white smoke of sulfuric acid. The residue is cooled and dissolved in water when heated. The solution was transferred to a beaker with a capacity of 300 cm, dilute with water to 150 cm, add 15 cmboiled nitric acid (1:1) and produce copper by electrolysis according to GOST 6689.1.

The electrolyte, after separation of copper is evaporated prior to the allocation of white smoke of sulfuric acid and then act as described in section 3.1.1.

3.3. For Nickel silver alloy

A sample of alloy weighing 1 g is placed in a beaker with a capacity of 300 cm, add 20 cmof a mixture of acid, cover with watch glass, glass or plastic plate and dissolved by heating.

The solution was evaporated to dryness. To the residue add 10 cmof concentrated hydrochloric acid and again evaporated to dryness. This operation is repeated 3 more times to complete removal of nitric acid.

Chilled dry residue is dissolved in 50 cmof hydrochloric acid 2 mol/DMwhen heated.

The solution was cooled and passed through a freshly prepared column chromatography with a speed of 5 cm/min for separation of Nickel and cobalt. A glass column and washed with 2 mol/DMhydrochloric acid to a negative reaction to Nickel eluate (sample dimethylglyoxime). To the eluate add 10 cmsulphuric acid (1:1) and the solution is evaporated until copious white smoke of sulfuric acid. The residue is cooled, dissolved in water by heating, dilute with water to 150 cm, add 15 cmboiled nitric acid (1:1) and then received, as indicated in paragraph 3.2.2.

4. PROCESSING OF THE RESULTS

4.1. The mass fraction of the sum of Nickel and cobalt () in percent is calculated by the formula

,

where is the mass of the cathode with the separated precipitate of Nickel and cobalt;

 — the mass of cathode, g;

 — the weight of the portion,

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 the table.

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* in accordance with GOST 25086.
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* On the territory of the Russian Federation GOST 8.315−97. — Note the manufacturer’s database.