GOST 6689.5-92

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  ГОСТ 6689.5-92

GOST 6689.5−92 Nickel, alloys Nickel and copper-Nickel. Methods of iron determination

GOST 6689.5−92

Group B59

STATE STANDARD OF THE USSR

NICKEL, ALLOYS NICKEL AND COPPER-NICKEL

Methods of iron determination

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

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. 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 6689.5−80

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard sets the photometric method for the determination of iron (at mass fraction of iron from 0.001 to 0.1%), titrimetric (mass fraction of iron with from 0.4 to 6.5%) and atomic absorption (at a mass fraction of iron from 0,004% to 6.5%) methods for determination of iron in Nickel and copper-Nickel alloys 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.

1. GENERAL REQUIREMENTS

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

2. PHOTOMETRIC METHOD for determination of IRON WITH the USE of 1,10-PHENANTHROLINE OR alpha, alpha'-dipyridyl

2. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON WITH THE USE OF 1,10-PHENANTHROLINE OR -DIPYRIDYL

2.1. The essence of the method

The method is based on measuring the optical density of the solution containing the complex of iron (II) with 1,10-fenantrolina or -dipyridil, in the presence of hydrochloric acid hydroxylamine after prior extraction of iron by coprecipitation with aluminum hydroxide.

2.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

Nitric acid according to GOST 4461 diluted 1:1 and 2% solution.

Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:2.

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

Acetic acid according to GOST 61.

Hydrofluoric acid according to GOST 10484.

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

Ammonium chloride according to GOST 3773.

Sodium acetate according to GOST 199.

Hydrogen peroxide according to GOST 10929, 5% solution.

Ammonium-aluminum sulfate (alum alimohammadian) according to GOST 4238, 10 g/lsolution of 10 g of alum was placed in a volumetric flask with a capacity of 1 DM, is dissolved in 150−200 cmof water with the addition of 20 cmof sulphuric acid (1:1) and topped to the mark with water.

Hydroxylamine hydrochloric acid according to GOST 5456, a solution of 10 g/DM, freshly prepared.

1,10-fenantrolin hydrochloric acid, a solution of 1.5 g/DM: 1.5 g of drug is placed in a beaker with a capacity of 200 cmand dissolved by heating in 50 cmof water with a few drops of concentrated hydrochloric acid; solution is placed in a volumetric flask with a capacity of 1 DMand topped to the mark with water. The solution was stored in a dark vessel.

-Dipyridyl, solution: 1.5 g of drug is dissolved in 50 cmof water when heated with a few drops of concentrated hydrochloric acid, the solution is placed in a volumetric flask with a capacity of 1 DMand dilute to the mark with water. The solution was stored in a dark vessel.

Buffer solution: 272 g sodium acetate and dissolve in 500 cmof water, add 240 cmof acetic acid, filter and add water to a volume of 1 DM.

A mixture of freshly prepared reagent: one part of a solution of hydroxylamine hydrochloric acid is mixed with one part of solution of 1,10-fenantrolina hydrochloric acid, or one part of the solution -dipyridine and three parts of the buffer solution.

The iron metal.

Standard iron solution

Solution a: 1.0 g iron is dissolved in 20 cmof nitric acid (1:1), the solution was boiled to remove oxides of nitrogen, cooled, placed in a volumetric flask with a capacity of 1000 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.001 g of iron.

Solution B: 10 cmsolution And placed in a measuring flask with volume capacity of 1000 cmand topped to the mark with water.

1 cmof solution B contains 0

, 00001 g of iron.

2.3. Analysis

2.3.1. For alloys containing not less than 0.1% of silicon and chromium and containing no tungsten

About 15 grams of alloy are placed in a beaker with a capacity of 300 cm, 200 cm addhydrochloric acid (1:1) and incubated at room temperature for about 3 min, stirring occasionally. Then poured hydrochloric acid, the chips are washed several times with water and dried in a drying oven at (110±10) °C. Of the thus purified chips take the weight (see table.1) place it in a glass with a capacity of 250 cm, add nitric acid (1:1) (see table.1), cover with watch glass, glass or plastic plate and dissolved by heating. Glass or the plate and the wall of the beaker rinse with water, add water up to 150 cm, 5 cmsolution alimohammadian alum, 5 g of ammonium chloride and concentrated ammonia solution before the formation of soluble ammonia complexes of Nickel and copper. The solution is kept at 60 °C for coagulation of the precipitate of iron hydroxide and aluminum. The precipitate was filtered off on a medium density filter, the beaker and the precipitate was washed 3−5 times with a hot solution of ammonia (1:100). The precipitate is dissolved in 10 cmof hydrochloric acid (1:1) and the filter 3−5 times washed with hot water, collecting the washings in the beaker, which carried out the deposition. In the analysis of alloys containing manganese, by dissolving the precipitate add a few drops of hydrogen peroxide solution. Deposition, filtering, washing and dissolving of the sediment again. The second time the dissolution of sediment carried on the filter in the presence of 5 cmof hydrogen peroxide solution.

Table 1

When the mass fraction of iron in the alloy is less than 0.002% solution is placed in a volumetric flask with a capacity of 100 cm, top up with water to 50 cm, adding 25 cmof a mixture of reagents, dilute to the mark with water and mix. After 30 min, measure the optical density of the solution on the spectrophotometer in a cuvette with a thickness of the light absorbing layer 5 cm at 510 nm or photoelectrocolorimeter with a green filter. Solution comparison is the solution of the reference experiment.

When the mass fraction of iron in excess of 0.002% solution is placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water, mix and take aliquot part (see table.1) in another volumetric flask with a capacity of 100 cm, dilute with water to 50 cmand then do as above.

2.3.2. For alloys containing more than 0.1% of chromium or silicon

A portion of the alloy (see table.1) is placed in a platinum Cup, add 1 cmhydrofluoric acid and 10 cmof nitric acid (1:1) and dissolved by heating. After cooling, rinse the walls of the Cup with water, add 10 cmsulphuric acid (1:1) and the solution is evaporated until a white smoke of sulfuric acid. The residue is cooled, add 30−40 cmof water, the solution is placed in a beaker with a capacity of 250 cm, dilute with water to 150 cmand then do as described in claim 2.3.1.

2.3.3. For alloys containing tungsten

A portion of the alloy (see table.1) is placed in a beaker with a capacity of 300 cm, add nitric acid (1:1) (see table.1), cover with watch glass, glass or plastic plate and dissolved by heating. Glass or plate and the side of the Cup then rinsed with water, the solution is evaporated to a syrupy condition, dilute with water to 60 cmand kept in a warm place for settling and clarification of the solution. The precipitate tungsten acid is filtered off on a double thick filter and washed with hot 20% nitric acid solution. The precipitate is discarded and the filtrate diluted with water to 200 cm, add 5 cmof a solution of alum alimohammadian and then do as mentioned in paragraph 2.3.1.

2.3.4. Construction of calibration curve

In a volumetric flask with a capacity of up to 100 cmis placed 0,5; 1,0; 3,0; 5,0; 7,0; 10,0; 20,0; 30,0 cmstandard iron solution B, dilute with water to 50 cmand further analysis is carried out as specified in clause 2.3.1.

2.4. Processing of the results

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

,

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

 — the weight of the portion corresponding to aliquote part of the solution,

2.4.2. Discrepancies in the results of three parallel measurements (rate of convergence) and the results of two tests are an indicator 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 and copper-Nickel alloys, approved under GOST 8.315*, or method of additions or by comparison of the results obtained by atomic absorption method in accordance with GOST 25086.
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* On the territory of the Russian Federation GOST 8.315−97, here and hereafter. — Note the manufacturer’s database.

3. TITRIMETRIC METHOD FOR DETERMINATION OF IRON

3.1. The essence of the method

The method is based on titration of iron (II) solution of potassium dichromate after pre-reduction of iron (III) to iron (II) dichloride tin with potentiometric or visual indication of the titration end point for diphenylamine as indicator.

3.2. Apparatus, reagents and solutions

Potentiometer with silver chloride reference electrode and a platinum indicator electrode.

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

Nitric acid according to GOST 4461.

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

Orthophosphoric acid according to GOST 6552.

A mixture of acids: 300 cmof sulphuric acid (1:1) and 300 cmof phosphoric acid diluted with water to 1 DM.

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

Tin dichloride, a freshly prepared solution of 100 g/lin hydrochloric acid (1:1).

Mercury dichloride, a solution of 40 g/DM.

Diphenylamine according to GOST 5825, a solution of 10 g/DMin concentrated sulfuric acid.

Potassium dichromate according to GOST 4220, 0,017 mol/DMsolution: 2,4519 g, dried for 2 h at (160±5) °C, dissolved in water, placed in a volumetric flask with a capacity of 1000 cmand topped to the mark with water.

1 cmof the mortar is 0,002792 g of iron.

Hydrofluoric acid according to GOST 10484.

Ammonium chloride according to GOST 3373.

Hydrogen peroxide according to GOST 10929, 30% solution.

Sodium salt diphenylaminochloroarsine acid solution 2 g/

DM.

3.3. Analysis

3.3.1. A portion of the alloy weight 2 g (when the mass fraction of iron is from 0.4 to 3.0%) or 1 g (in mass percentage of iron in excess of 3%) dissolved in 20 cmof hydrochloric acid (1:1) and 10 cmof nitric acid in a beaker with a capacity of 600 cmwhen heated. After dissolution the solution is diluted with water to 150 cm. In the analysis of alloys with a mass fraction of silicon in excess of 0.05% of the sample is dissolved in a platinum Cup 20 or 10 cmof nitric acid (1:1) and 1 cmhydrofluoric acid when heated, add 10 cmsulphuric acid (1:1), evaporated until white smoke of sulfuric acid; the residue is dissolved in 20−30 cmof water and the solution transferred to a beaker with a capacity of 600 cm, add 5 cmof nitric acid (1:1) and the solution diluted with water to 150 cm.

Add 5 g of ammonium chloride and ammonia to the formation of the soluble ammonia complex of Nickel and copper.

The solution is kept at 60 °C for coagulation of the precipitate of iron hydroxide. The precipitate was filtered off on a medium density filter, the beaker and the precipitate was washed 3−5 times with a hot solution of ammonia (1:100). The precipitate is dissolved in 10 cmof hydrochloric acid (1:1) with a few drops of hydrogen peroxide in a glass, which conducted the deposition, and the filter washed with hot water. Deposition, filtering, washing and dissolving of the sediment again. The solution is heated to boiling and recover trivalent iron to bivalent by adding a few drops of solution of tin dichloride. Then the solution was cooled, add 5 cmof a solution of dichloride of mercury 15 cmof the mixture of acids, dilute with water to 200 cmand titrated solution of potassium dichromate potentiometric up to the jump capacity or add a few drops of solution of diphenylamine or solution of the sodium salt diphenylaminochloroarsine acid and titrated to the purple

color.

3.4. Processing of the results

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

,

where is the volume of potassium dichromate solution consumed for titration, cm;

0,002792 mass concentration is 0.017 mol/DMsolution of potassium dichromate of iron, g;

 — the mass of alloy,

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 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 a comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.

4. ATOMIC ABSORPTION METHOD FOR DETERMINATION OF IRON

4.1. The essence of the method

The method is based on measuring the absorption of iron atoms 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 iron.

Nitric acid according to GOST 4461 and diluted 1:1 and 1:100.

Hydrochloric acid according to GOST 3118 and 1 and 2 mol/DMsolutions.

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.

Iron metal carbonyl or State standard sample N 666−81 P type 1.

Iron standard solution: 0.1 g of iron was dissolved with heating in 10 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 0.0001 g of iron.

Copper according to GOST 859*.
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* On the territory of the Russian Federation GOST 859−2001, here and hereafter. — Note the manufacturer’s database.

Standard copper solution: 10 g of copper was dissolved with heating in 80 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.

1 cmof the solution contains 0.1 g of copper.

Nickel GOST 849*.
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* On the territory of the Russian Federation GOST 849−2008. — Note the manufacturer’s database.

A standard solution of Nickel: 10 g of Nickel is dissolved by heating in 80 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.

1 cmof the solution contains 0.1 g of Nickel.

4.3. Analysis

4.3.1. For alloys not containing tin, silicon, chromium, tungsten and titanium

A portion of the alloy by weight, are given in table.3, is dissolved by heating in 10−20 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. When the mass fraction of iron in excess of 1.0% of 10 cmof sample solution is transferred to a volumetric flask with a capacity of 100 cm, add 10 cmof 2 mol/DMhydrochloric acid solution and add water to the mark. At the same time spend control experience. Measure the atomic absorption of iron in the flame of acetylene-air at a wavelength of 248.3 nm parallel to the calibration solutions.

Table 3

4.3.2. For alloys with a mass fraction of tin in excess of 0.05%

A portion of the alloy (see table.3) was dissolved with heating in 10 cmof a mixture of acids. The solution was transferred to a volumetric flask with a capacity of 100 cmand topped to the mark of 1 mol/DMhydrochloric acid solution. When the mass fraction of iron in excess of 1.0% of 10 cmof sample solution is transferred to a volumetric flask with a capacity of 100 cmand topped to the mark of 1 mol/DMhydrochloric acid solution. At the same time spend control experience. Measure the atomic absorption, as described in paragraph 4.3.1.

4.3.3. For alloys containing silicon, titanium and chromium

A portion of the alloy (see table.3) is placed in a platinum Cup and dissolve by heating in 10−20 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. When the mass fraction of iron in excess of 1.0% of 10 cmof sample solution is transferred to a volumetric flask with a capacity of 100 cm, add 10 cmof 2 mol/DMhydrochloric acid solution and add water to the mark. At the same time spend control experience. Measure the atomic absorption of iron, as stated in claim 4.3

.1.

4.3.4. For alloys containing tungsten

A portion of the alloy (see table.3) was dissolved with heating in 10−20 cmof nitric acid (1:1), then add 30 cmof hot water and the precipitate tungsten acid is filtered off on a tight filter and washed with hot nitric acid (1:100). The filtrate is transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark. When the mass fraction of iron in excess of 1.0% of 10 cmof sample solution is transferred to a volumetric flask with a capacity of 100 cm, add 10 cmof 2 mol/DMhydrochloric acid solution and add water to the mark. At the same time spend control experience. Measure the atomic absorption of iron, as stated in claim 4.3.1

.

4.3.5. Construction of calibration curve

In six of the seven volumetric flasks with a capacity of 100 cmis placed 0,8; 2,0; 4,0; 6,0; 8,0 and 10,0 cmstandard solution of iron, which corresponds to 0.08; 0,2; 0,4; 0,6; 0,8 and 1,0 mg of iron. To all flasks add 10 cmof 2 mol/DMhydrochloric acid solution.

For the mass concentration of iron less than 0.1% aliquote add volumes of standard solutions (see table.3) copper (if copper is the basis of alloy) or Nickel (when Nickel is the substrate) and top up with water to the mark. Measure the atomic absorption of iron, as stated in claim 4.3.1. According to the obtained results build a calibration curve.

4.4. Processing of the results

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

,

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

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

 — the solution volume, 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 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 and copper-Nickel alloys, approved under GOST 8.315, or a comparison of the results obtained photometric or titrimetric methods, in accordance with GOST 25086.