GOST 6689.2-92

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  ГОСТ 6689.2-92

GOST 6689.2−92 Nickel, alloys Nickel and copper-Nickel. Methods for determination of Nickel

GOST 6689.2−92

Group B59

STATE STANDARD OF THE USSR

NICKEL, ALLOYS NICKEL AND COPPER-NICKEL

Methods for determination of Nickel

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

OXTO 1 709

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

3. REPLACE GOST 6689.2−80

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies a gravimetric, titrimetric methods for the determination of Nickel (at a mass fraction of Nickel in excess of 0.5%) and atomic absorption method for the determination of Nickel (at a mass fraction of Nickel from 0.5 to 7%) in 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. GRAVIMETRIC METHOD FOR THE DETERMINATION OF NICKEL

2.1. The essence of the method

The method is based on precipitation of Nickel in ammoniacal solution dimethylglyoxime in the form of slightly soluble chelation in the presence of citric or tartaric acid.

2.2. Reagents and solutions

Hydrochloric acid according to GOST 3118 and diluted 3:1 and 1:10.

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

Hydrofluoric acid according to GOST 10484.

Sulfuric acid according to GOST 4204, diluted 1:1, 1:4 and 1:100.

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

Citric acid according to GOST 3652, a solution of 400 g/DM.

Tartaric acid according to GOST 5817, a solution of 400 g/DM;

Ammonia water according to GOST 3760 and diluted 1:100.

Ammonium neccersarily according to GOST 20478, a solution of 250 g/DM.

The technical rectified ethyl alcohol according to GOST 18300 and diluted 1:3.

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

Sodium atomistically according to GOST 4197, solution 20 g/DM.

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

Sodium acetate according to GOST 199, a solution of 500 g/DM

.

2.3. Analysis

2.3.1. For alloys containing less than 0.5% copper, the alloy chromel

A sample weighing 1 g is 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 or glass plate and the side of the Cup then rinsed with water, the solution is placed in a volumetric flask with a capacity of 500 cmand top up with water to the mark. If the alloy contains tungsten, the solution was evaporated to dryness. To the dry residue add 10 cmof concentrated hydrochloric acid and again evaporated to dryness. The dry residue was dissolved with heating in 10 cmof concentrated hydrochloric acid and diluted with 100 cmof hot water. Tungsten precipitated acid is filtered off on paper, two medium density filter and washed with hot hydrochloric acid solution (1:10) until the disappearance of Nickel ions in the washing water (test with dimethylglyoxime according to GOST 6689.3, p.3.1.1). The precipitate tungsten acid on the filter can be used for the determination of tungsten GOST 6689.11.

For the mass concentration in the alloy more than 0.1% silicon in the solution add 10 cmsulphuric acid (1:1) and evaporated until copious white smoke of sulfuric acid. To the cooled residue carefully added a small amount (about 10 cm) of cold water and then poured into 100 cmof hot water and dissolved by heating.

The precipitate of silicic acid is filtered off on a medium density filter, washed with hot water and discarded.

The filtrate after separation of the tungsten or silicon is placed in a volumetric flask with a capacity of 500 cmand topped to the mark with water.

In a glass with a capacity of 600 cmis placed aliquot part of the solution, equal to 10 cm, and diluted with water to 300 cm. The solution is heated to 65−70 °C, add 20 cmof a solution of citric or tartaric acid, neutralized with ammonia to slightly acid reaction (pH 4−5) on universal indicator paper and with good stirring, add 25 cmof the solution dimethylglyoxime and 2−3 cmof concentrated ammonia solution until a slightly alkaline environment. Solution and the precipitate is kept in a warm place for 40−50 min and then filtered off the precipitate on the filter medium density 4−5 times and washed with hot water. The filter cake is dissolved in 30 cmof hydrochloric acid (3:1), collecting the solution in a glass, which conducted the deposition. The filter is washed with hot water and solution into the beaker dilute with hot water up to 300 cm. The Nickel deposition is repeated, adding 5 cmof a solution of citric or tartaric acid, 25 cmsolution dimethylglyoxime and ammonia to slightly alkaline environment. Solution and the precipitate is kept in a warm place for 40−60 minutes (you can leave for 12 hours). The precipitate was filtered on a previously weighed filter crucible N 3 when the suction water jet pump. Precipitate was washed 5−7 times in hot water and twice with ethanol (1:3). The crucible with the precipitate is dried in a drying Cabinet at 105−110 °C to constant weight

and weighed.

2.3.2. For the alloy chromel

A sample weighing 0.5 g were placed in a glass with a capacity of 300 cm, add 20 cmof the mixture of acids to dissolve, cover with a watch glass, a glass or plastic plate and dissolved by heating. After the dissolution of a glass or plate and the side of the Cup and rinse with water, add 10 cmsulphuric acid (1:1) and removed prior to the allocation of white smoke of sulfuric acid. The cooled precipitate is dissolved in 100 cmof water when heated.

The separated precipitate of silicic acid is filtered off on a medium density filter and washed 5−7 times in hot sulfuric acid (1:100). The precipitate is discarded or used for determination of silicon GOST 6689.7.

The filtrate is diluted with water to 250 cmand heated to 65−70 °C. To the heated solution was added 10 cmof a solution of silver nitrate, 10 cmsolution naternicola ammonium and boil for 15−20 min until complete destruction of excess ammonium naternicola that are known by the termination of allocation of bubbles of oxygen. If the sample contains manganese, rebuilt it, adding dropwise a solution of sodium attestatio. The solution was cooled, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix. In a glass with a capacity of 600 cmaliquote take a part equal to 20 cm, and lead further analysis, as indicated in claim 2.

3.1.

2.3.3. For alloys containing more than 0.5% copper (excluding alloys MNGMT 5−1-0,2−0,2, Nickel-silver and manganin)

A portion of the alloy (tab.1) is placed in a beaker with a capacity of 300 cm, add 20 cmof nitric acid (1:1), cover with watch glass, glass or plastic plate and dissolved by heating.

Table 1

After dissolution of the alloy or glass plate and the walls of the beaker rinse with water, add 7 cmof sulphuric acid (1:4), dilute with water to 150 cmand produce copper by electrolysis according to GOST 6689.1.

When the mass fraction of Nickel less than 1% is used all the electrolyte, but at a higher Nickel content of the electrolyte is transferred to a volumetric flask with a capacity of 500 cmand topped to the mark with water. In a glass with a capacity of 600 cmis placed aliquot part of the solution (table.1) and further analysis are as indicated in claim 2.3.1.

2.3.4. For the alloy MNGMT 5−1-0,2−0,2

A sample weighing 1 g is placed in a platinum Cup, pour 15 cmof nitric acid (1:1) and 1 cmhydrofluoric acid, cover the Cup lid is made of platinum or PTFE and dissolved by heating. Cool, add 10 cmsulphuric acid (1:1) and evaporated to release white smoke of sulfuric acid. The residue is cooled, add 30−50 cmof water and dissolved by heating. Solution bias in a glass with a capacity of 300 cm, is diluted to 150 cm, add 10 cmboiled nitric acid (1:1) and produce copper by electrolysis according to GOST 6689.1.

In the electrolyte after separation of the copper, add ammonia until a complete transition of Nickel in a soluble ammonia complex, and kept in a warm place for coagulation of the precipitate hydroxides of iron and titanium. The precipitate was filtered off on a medium density filter and washed precipitate and a glass of ammonia solution (1:100). The precipitate is discarded. The filtrate is acidified with hydrochloric acid to slightly acid reaction (pH 4−5), transferred to a volumetric flask with a capacity of 500 cmand topped to the mark with water. In a glass with a capacity of 600 cmis placed aliquot part of the solution (table.1) and further analysis are as indicated in claim 2.3

.1.

2.3.5. For alloys Nickel silver and manganin

A portion of the alloy (tab.1) is placed in a beaker with a capacity of 300 cmadd 30 cmof nitric acid (1:1), cover with watch glass, glass or plastic plate and dissolved by heating.

After dissolution of the alloy or glass plate and the walls of the beaker rinse with water, add 7 cmof sulphuric acid (1:4), dilute with water to 150 cmand separating the copper by electrolysis according to GOST 6689.1.

In the analysis Sventevith Nickel silver sulfuric acid is added only after 30 minutes after the start of electrolysis.

After the separation of copper electrolyte were placed in a glass with a capacity of 600 cmor volumetric flask with a capacity of 500 cm, aliquote take part (see table.1) and dilute with water to 300 cm. The solution is heated to 65−70 °C, add 25 cmof the solution dimethylglyoxime with stirring and a solution of sodium acetate to the appearance of the precipitate, and then an excess of 4 cm. A solution of sodium acetate is added to the middle of the solution and not only on the walls of the glass. The solution is kept in a warm place for 40−60 minutes and further analysis are as indicated in claim 2.3

.1.

2.4. Processing of the results

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

,

where is the mass of sediment dimethylglyoxime Nickel, g;

0,2032 — dimethylglyoxime conversion rate of Nickel to Nickel;

 — weight 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) Nickel and copper-Nickel alloys, approved under GOST 8.315*, or a comparison of the results obtained by the titrimetric method in accordance with GOST 25086.
________________
* On the territory of the Russian Federation GOST 8.315−97, here and hereafter. — Note the manufacturer’s database.

3. TITRIMETRIC METHOD FOR THE DETERMINATION OF NICKEL

3.1. The essence of the method

The method is based on precipitation of Nickel in ammoniacal solution dimethylglyoxime in the form of slightly soluble chelation in the presence of citric or tartaric acid and determining the Nickel chelatometric titration with eriochrome black T as indicator.

3.2. Reagents and solutions

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

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

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

Citric acid according to GOST 3652, a solution of 400 g/DM.

Tartaric acid according to GOST 5817, a solution of 400 g/DM.

Ammonia water according to GOST 3760.

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

Ammonium chloride according to GOST 3773.

Ammonium neccersarily according to GOST 20478, a solution of 250 g/DM.

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

Sodium atomistically according to GOST 4197, solution 20 g/DM.

Sodium acetate according to GOST 199, a solution of 500 g/DM.

Hydrogen peroxide according to GOST 10929.

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

Methyl red indicator in 0.1% alcohol solution.

Eriochrome black , saturated aqueous solution.

Buffer solution with pH 10: 570 cmammonia is added 70 g of ammonium chloride and diluted to 1 DMwith water.

Magnesium sulfate according to GOST 4523, 0.05 mol/DMthe solution of 12.33 g of magnesium sulfate dissolved in 500 cmof water, the solution was transferred to volumetric flask with a capacity of 1 DMand topped to the mark with water.

Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water (Trilon B) according to GOST 10652; 0.05 mol/DMsolution: 18,612 g Trilon B dissolved in 500 cm, the solution is placed in a volumetric flask with a capacity of 1 DMand topped to the mark with water.

Nickel brand H0 according to GOST 849*.
________________
* On the territory of the Russian Federation GOST 849−2008, here and hereafter. — Note the manufacturer’s database.

A standard solution of Nickel: 1 g of Nickel is dissolved in a beaker with a capacity of 250 cmto 20 cmof hydrochloric acid (1:1) and 10 cmof hydrogen peroxide, added in small portions. After reconstitution, the solution boiled for 1 min to decompose excess hydrogen peroxide, cooled, 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 Nickel.

3.2.1. The installation of the mass concentration of the solution Trilon B

In a glass or flask with a capacity of 600 cmis placed 10 cmto the standard solution of Nickel, diluted with water to a volume of 300 cmand then do as described in claim 3.3.1.

Mass concentration of the solution Trilon B (), expressed in grams of Nickel per 1 cmof a solution, calculated by the formula

,

where is the mass of Nickel in aliquotes part taken for the titration, g;

 — volume of solution Trilon B, mass concentration of which is determined, cm;

 — the volume of solution of magnesium sulfate, used for titration of Trilon B, cm;

 — a correction factor to the mass concentration of the solution Trilon B.

3.2.2. Setting the correction factor to the mass concentration of the solution Trilon B ()

In a glass or flask with a capacity of 600 cmtaken from burette 10 cmof the solution Trilon B, add 1 drop of sodium hydroxide solution, 7 cmbuffer solution, dilute with water to a volume of 300 cmand then add 4−5 drops of solution of eriochrome black and titrated with a solution of sulphate of magnesium to transition blue-green color in lilac.

Correction factor () is calculated by the formula

,

where  — volume of solution Trilon B taken in the titration, cm;

 — the volume of solution of magnesium sulfate, spent on titration, sm.

3.3. Analysis

3.3.1. For alloys with a mass fraction of copper is less than 0.5%, except for the alloy chromel

Preparation for the analysis carried out according to claim 2.3.1. In a glass or flask with a capacity of 600 cmis placed aliquot part of the solution, equal to 10 cm, dilute with water to 300 cm, add 20 cmof a solution of citric or tartaric acid, neutralized with ammonia to pH 4−5 by universal indicator paper and with vigorous stirring the solution was added to 25 cmof a solution dimethylglyoxime and 2−3 cmof concentrated ammonia solution until a slightly alkaline environment (pH 10) and 2−3 drops excess. Solution and the precipitate is kept in a warm place for 40−50 min, then filtered off the precipitate on the filter medium density 4−5 times and washed with hot water. The washed precipitate is washed from the filter with a jet of hot water into a glass, which conducted the deposition. The filter is washed first 30 cmof a hydrochloric acid solution and then with hot water.

The solution is heated to boiling and slightly boil while stirring until complete dissolution of the precipitate. Cool the solution to room temperature, dilute with water to 300 cm, adding 25 cmof the solution Trilon B, is neutralized with sodium hydroxide solution in methyl red (2−3 drops) until the pink color transition to yellow. Poured from a burette 7 cmbuffer solution, 5 drops of a solution of eriochrome black and titrated with a solution of sulphate of magnesium to transition blue-green color in siren

ewww.

3.3.2. For the alloy chromel

Preparation for the analysis carried out according to claim 2.3.2. In a glass or flask with a capacity of 600 cmis placed aliquota part is 20 cm, and further analysis are as indicated in claim 3.3.1.

3.3.3. For alloys with a mass fraction of copper in excess of 0.5% (excluding alloys MNGMT 5−1-0,2−0,2, Nickel-silver and manganin)

Preparation for the analysis carried out according to claim 2.3.3. In a glass or flask with a capacity of 600 cmis placed aliquot part (see table.1) and further analysis are as indicated in claim 3.3.1.

3.3.4. For alloys MNGD 5−1-0,2−0,2

Preparation for the analysis carried out according to claim 2.3.4. In a glass or flask with a capacity of 600 cmis placed aliquot part of the solution (see table.1) and further analysis are as indicated in claim 3.3.1.

3.3.5. For alloys Nickel silver and manganin

Preparation for the analysis carried out according to claim 2.3.5. In a glass or flask with a capacity of 600 cmis placed aliquot part (see table.1) and further analysis are as indicated in claim 3.3.1.

3.4. Processing of the results

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

,

where  — volume of solution Trilon B taken in the titration, cm;

 — the volume of solution of magnesium sulfate consumed in the titration, cm;

 — correction factor (p.3.2.2);

 — mass concentration of the solution Trilon B (p.3.2.1) Nickel, g/cm;

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

G.

3.4.2. 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 allowable differences specified in table.2.

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

4. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF NICKEL

4.1. The essence of the method

The method is based on measuring the absorption of light by atoms of Nickel, formed during the introduction of the analyzed solution in the flame acetylene-air.

4.2. Apparatus, reagents and solutions

Atomic absorption spectrometer with a radiation source for Nickel.

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

Hydrofluoric acid according to GOST 10484.

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

Nickel GOST 849.

A standard solution of Nickel: 1 g of Nickel is dissolved by heating in 15 cmof nitric acid (1:1). The solution was 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 of Nickel.

4.3. Analysis

4.3.1. For alloys not containing silicon and titanium

A sample of alloy weighing 0.1 g was dissolved with heating in 10 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark.

Measure the atomic absorption of Nickel in the flame acetylene-air at a wavelength of 341,5 nm parallel to the calibration solutions.

4.3.2. For alloys containing silicon and titanium

A sample of alloy weighing 0.1 g was placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid (1:1) and 2 cmhydrofluoric acid. Then add 10 cmsulphuric acid (1:1) and evaporated until a white smoke of sulfuric acid. Cup cooled and the residue is dissolved in 50 cmof water when heated. The solution was transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark. Measure the atomic absorption of Nickel, as specified in clause 4.3.1.

4.3.3. Construction of calibration curve

Eight volumetric flasks with a capacity of 100 cmplaced 0,5; 1,0; 2,0; 3,0; 4,0; 5,0; 6,0 and 7.0 cmof standard solution of Nickel, which corresponds to 0,5; 1,0; 2,0; 3,0; 4,0; 5,0; 6,0 and 7.0 mg of Nickel. To all flasks add 10 cmof nitric acid (1:1) and topped to the mark with water. Measure the atomic absorption of Nickel, 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 Nickel () in percent is calculated by the formula

,

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

 — the volume of the sample solution, cm;

 — the weight of the portion of the sample,

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.3.

Table 3

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) Nickel and copper-Nickel alloys, approved under GOST 8.315, or by a method of additives in accordance with GOST 25086.