GOST 6689.15-92

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  ГОСТ 6689.15-92

GOST 6689.15−92 Nickel, alloys Nickel and copper-Nickel. Methods for determination of antimony

GOST 6689.15−92

Group B59

STATE STANDARD OF THE USSR

NICKEL, ALLOYS NICKEL AND COPPER-NICKEL

Methods for determination of antimony

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

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

3. REPLACE GOST 6689.15−80

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies the extraction-photometric and polarographic methods for the determination of antimony (in mass fraction of antimony from 0.0005 to 0.01%) and atomic absorption method for the determination of antimony (in mass fraction of antimony from 0.001 to 0.05%) 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. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF ANTIMONY WITH BRILLIANT GREEN APPLICATION

2.1. The essence of the method

The method is based on the formation of pentavalent antimony in hydrochloric acid medium of hexachlorobuta brilliant green of its extraction with toluene, and measuring the optical density of the extract. In the case of copper-Nickel alloys antimony is pre-separated by coprecipitation with metalbands acid.

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.

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

Sulfuric acid according to GOST 4204, and diluted 1:5.

Hydrofluoric acid according to GOST 10484.

Ammonium nitrate according to GOST 22867.

The washing liquid of 10 g of the ammonium nitrate is dissolved in 200 cmof water, add 10 cmof concentrated nitric acid, add water to 1 DMand stirred.

Tin dichloride according to NTD, a freshly prepared solution of 10 g/lin hydrochloric acid, diluted 1:1.

Sodium atomistically according to GOST 4197, solution 100 g/DM.

Carbamide (urea) GOST 6691, saturated solution: 100 g of urea dissolved in 100 cmof hot water.

Brilliant green, aqueous solution 2 g/DM.

Toluene according to GOST 5789.

Sodium sulphate anhydrous according to GOST 4166.

Tin metal, with antimony content is not more than 3·10%.

Antimony brand Su0 according to GOST 1089.

Standard solutions of antimony.

Solution a: 0.05 g of antimony is dissolved by heating in 25 cmconcentrated sulphuric acid. The solution was then cooled, placed in a volumetric flask with a capacity of 500 cm, made up to the mark with sulphuric acid (1:5).

1 cmof the solution contains 0.0001 g of antimony.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with hydrochloric acid (1:1) and stirred; prepared on the day of application.

1 cmof solution B contains 0,00001 g of antimony.

Solution: 10 cmof solution B is placed in a volumetric flask with a capacity of 100 cm, made up to the mark with hydrochloric acid (1:1); prepared on the day of application.

1 cmof the solution contains 0,00000

1 g of antimony.

2.3. Analysis

2.3.1. For alloys with a mass fraction of silicon and chromium less than 0.1%, not containing tungsten

A portion of the alloy (see table.1) is placed in a beaker with a capacity of 250 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 sample clock or the glass plate and the walls of the beaker rinse with water, add 3 cmof concentrated sulfuric acid and is evaporated prior to the allocation of white smoke of sulfuric acid. The side of the Cup rinse with water and repeat the evaporation to start the selection of a white smoke of sulfuric acid two more times.

When the mass fraction of antimony in the alloy is less than 0.001% residue is cooled and dissolved by heating in 20 cmof hydrochloric acid (1:1). The solution was then cooled, placed in a separatory funnel with a capacity of 250 cmand the walls of the glass should be rinsed with 5 cmof hydrochloric acid (1:1). To the solution add 1−2 drops of solution of tin dichloride, mix and leave for 1 min, then add 1 cmof solution azotistykh sodium, mixed well and left for 5 min. Add 1 cmof a saturated solution of urea, mix 30 g* injected 140 cmwater, 1 cmdiamond green, 30 cmof toluene and shake the funnel for 1 min. After phase separation, the lower aqueous layer discarded, and the organic layer placed in a dry glass with a capacity of 50 cm, containing 0.3−0.5 g anhydrous sodium sulphate, or filtered through a dry paper filter. After 10 minutes measure the optical density of the extract on a photoelectrocolorimeter with a red light filter in a cuvette with a thickness of the light absorbing layer 5 cm or on spectrophotometer at 640 nm in a cuvette with the thickness of the light absorbing layer 1 see Solution comparison serves to extract the reference experiment.
_______________
* Consistent with the original. — Note the manufacturer’s database.

When the mass fraction of antimony in the alloy greater than 0.001% residue after evaporation with sulphuric acid is cooled and is dissolved by heating in 30 cmof hydrochloric acid (1:1). The solution was then cooled, placed in a volumetric flask with a capacity of 50 cmand then filled to the mark with hydrochloric acid (1:1), aliquot part 10 cmis placed in a separating funnel with a capacity of 100−150 cm, add 1−2 drops of solution of tin dichloride and allowed to stand for 1 min. Then add 1 cmof solution azotistykh sodium, mixed well and left for 5 min. then add 1 cmof urea and stirred for 30 seconds, then add the 55 cmof water, 2 cmof a solution of brilliant green, 30 cmof toluene and shaken for 1 min.

Then do as indicated above in the analysis of alloys with a mass fraction of antimony

less than 0.001%.

2.3.2. For alloys with a mass fraction of chlorine or silicon is more than 0.1%

A portion of the alloy (see table.1) is placed in a platinum Cup, add 20 cmof nitric acid (1:1), 1 cmhydrofluoric acid and dissolved by heating. After cooling the walls of the Cup and rinse with water, add 3 cmof concentrated sulfuric acid and is evaporated prior to the allocation of white smoke of sulfuric acid. A Cup of cooled, rinse the walls of the Cup with water and repeat the evaporation to start the selection of a white smoke of sulfuric acid two more times. Further analysis are as indicated 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 250 cm, add 40−60 cmof the mixture of acids to dissolve, cover with a watch glass, a glass or plastic plate and dissolved by heating. Glass or the plate and the wall of the beaker rinse with water, add 5 cmof concentrated sulfuric acid and was boiled down to 10−12 cm.

After cooling, to the solution was added 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 in the filtrate determine the antimony on the day of analysis. This evaporated solution, not allowing to boil, until the beginning of the allocation of white smoke of sulfuric acid. Rinse walls of beaker with water and repeat the evaporation to start the selection of a white smoke of sulfuric acid two more times. Further analysis are as indicated in claim 2.3.1.

2.3.4. For copper-Nickel alloys

A portion of the alloy (see table.1) is placed in a beaker with a capacity of 250 cm, add 0.01 g of tin metal, 20 cmof nitric acid (1:1), cover with watch glass, glass or plastic plate and dissolved by heating. After dissolution of the sample or glass plate and the walls of the beaker rinse with water, add 20 cmof water, a small amount of filter-paper pulp and leave for 1−2 hours in a warm bath. The precipitate was filtered off on a tight filter, a glass and a precipitate was washed 10−12 times with wash fluid. The filter with precipitate was placed in a beaker, which was carried out the precipitation, add 10−15 cmof concentrated sulfuric acid, 20−35 cmof concentrated nitric acid and the solution is evaporated prior to the allocation of thick white smoke of sulfuric acid. If the remaining solution is colored, add another 5−10 cmof nitric acid and repeat the evaporation to start the selection, the dense white smoke of sulfuric acid. The glass is cooled, the walls should be rinsed with water and evaporated the solution until damp salts.

When the mass fraction of antimony in the alloy is less than 0.001% residue after cooling, add 7 cmof hydrochloric acid (1:1) was heated to dissolution, and the solution placed in a separatory funnel with a capacity of 100−150 cmand the side of the Cup rinsed 3 cmof hydrochloric acid (1:1) and further analysis are as indicated in claim 2.3.1 in the determination of antimony in the alloy is less than 0.001%.

When the mass fraction of antimony in the alloy greater than 0.001% the residue is dissolved under heating in 30 cmof hydrochloric acid (1:1), the solution was cooled, placed in a volumetric flask with a capacity of 50 cmand then filled to the mark with hydrochloric acid (1:1). Aliquot part 10 cmis placed in a separating funnel with a capacity of 100−150 cm. Further analysis are as indicated in claim 2.3.1 in the determination of antimony greater than 0.001%.

Solution comparison is the solution of the control experiment conducted through the entire course and

analysis.

2.3.5. Construction of calibration graphs

2.3.5.1. The calibration graph for the determination of antimony is less than 0.001%

In a separating funnel with a capacity of 250−300 cmis placed 1,0; 2,0; 3,0; 4,0; 5,0 and 6,0 cmstandard solution of antimony, add hydrochloric acid (1:1) to 25 cm, add 1−2 drops of solution of tin dichloride and allowed to stand for 1 min. Further analysis are as indicated in claim 2.3.1 in the determination of antimony is less than 0.001%.

2.3.5.2. The calibration graph for the determination of antimony greater than 0.001%

In a separating funnel with a capacity of 100−150 cmis placed 1,0; 2,0; 3,0; 4,0; 5,0 and 6,0 cmstandard solution of antimony, add hydrochloric acid (1:1) up to 10 cm, 1−2 drops of solution of tin dichloride and allowed to stand for 1 min. Further analysis are as indicated in claim 2.3.1 in the determination of antimony greater than 0.001%.

2.4. Processing of the results

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

,

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

 — 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) of Nickel, Nickel and copper-Nickel alloys, approved under GOST 8.315*, or method of additions or by comparison of the results obtained polarographic or 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. EXTRACTION-PHOTOMETRIC METHOD for the DETERMINATION of ANTIMONY WITH CRYSTAL VIOLET APPLICATION (WITH MASS FRACTION of ANTIMONY FROM 0.001 to 0.01%)

3.1. The essence of the method

The method is based on the formation of pentavalent antimony in hydrochloric acid environment hexachlorobuta crystal violet, extracting it with toluene, and measuring the optical plotnosti painted extract after separation of the antimony from the main components of alloys by coprecipitation with manganese dioxide.

3.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

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

Hydrochloric acid according to GOST 3118 and diluted 7:3.

The mixture of acids for reconstitution of concentrated nitric and hydrochloric acids in a ratio of 1:3.

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

Hydrofluoric acid according to GOST 10484.

Ammonia water according to GOST 3760.

Potassium permanganate according to GOST 20490, a solution of 40 g/DM.

Manganese sulfate according to GOST 435, a solution of 100 g/DM.

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

Sodium atomistically according to GOST 4197, solution 100 g/DM.

Carbamide (urea) GOST 6691, saturated solution: 100 g of urea dissolved in 100 cmof hot water.

Crystal violet, an aqueous solution 2 g/DM.

Toluene according to GOST 5789.

Sodium sulfate according to GOST 4166, anhydrous.

Antimony brand Su00 or Su0 according to GOST 1089.

Standard solutions of antimony

Solution a: 0.1 g of antimony is dissolved by heating in 50 cmof concentrated sulfuric acid. The solution was then cooled, placed in a volumetric flask with a capacity of 1000 cm, 175 cm addedsulfuric acid (1:1), cooled and topped to the mark with water.

1 cmof the solution contains 0.0001 g of antimony.

Solution B: 10 cmsolution is placed in a volumetric flask with a capacity of 100 cm, add 70 cmof concentrated hydrochloric acid and dilute to the mark with water prepared on the day of application.

1 cmof solution B contains 0,00001 g

antimony.

3.3. Analysis

3.3.1. For alloys with a mass fraction of silicon is less than 0.1%, not containing chromium and tungsten

A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 250 cm, add 20 cmof nitric acid (1:1), cover with watch glass, glass or plastic plate and dissolved by heating. The walls of the beaker and watch glass or plate rinse with water, add water up to 100 cm, neutralized with ammonia until the appearance of turbidity does not disappear while mixing (pH 3 by universal indicator paper), add 0.5 cmof concentrated nitric acid and 1 cmof solution of potassium permanganate. Beaker cover watch glass, glass or plastic plate and the solution is heated nearly to boiling. Add 2cmof a solution of manganese sulfate and boiled for 2 min (at a mass proportion of manganese in the alloy, a 2% solution of sulphate of manganese is not added). The solution is kept for 1 h at 30−40 °C. the Separated precipitate was filtered off on a tight filter and washed 4−5 times with hot nitric acid (1:100). The filter with precipitate was placed in a glass that has been used for the precipitation, add 10−15 cmof concentrated sulfuric acid, 20−25 cmof concentrated nitric acid and evaporated prior to the allocation of thick white smoke of sulfuric acid. If the remaining solution is colored, add 5−10 cmof concentrated nitric acid and repeat the evaporation. After cooling, the side of the Cup then rinsed with water and evaporated the solution until damp salts.

When the mass fraction of antimony in the alloy is less than 0.005% residue after cooling, add 7 cmof hydrochloric acid (7:3) and heated to dissolve the salts. The solution was placed in a separating funnel with a capacity of 100−150 cm, the glass is rinsed 3 cmof hydrochloric acid (7:3).

When the mass fraction of antimony in the alloy in excess of 0.005% residue after cooling, add 10 cmof hydrochloric acid (7:3), heated to dissolve the salts, and after cooling, the solution was placed in a volumetric flask with a capacity of 25 cmand then filled to the mark with hydrochloric acid (7:3). Aliquot part of the solution was 10 cmplaced in a separating funnel with a capacity of 100−150 cm, add 1−2 drops of solution of tin dichloride to a bleaching solution, mix and leave for 1 min In a separating funnel add 1 cmof a solution of sodium attestatio, funnel closed with a stopper, shake for 2 min and the funnel open. After 2 min add 1 cmof a solution of urea and stirred with 30, then add 70 cmof water, 10 drops of a solution of crystal violet, 25 cmof toluene and shaken for 1 min. After phase separation, the lower layer is discarded and the organic layer placed in a dry glass with a capacity of 50 cmcontaining 0.3−0.5 g anhydrous sodium sulphate, or filtered through a dry paper filter and, after 10−15 min, measure the optical density of the extract on a photoelectrocolorimeter with a red light filter in a cuvette with a thickness of the light absorbing layer 2 cm or on the spectrophotometer at 610 nm in a cuvette with the thickness of the light absorbing layer 1 see Solution comparison serves to extract the reference experiment.

Note. If the analysis will not be completed during the day, it can be interrupted after the deposition of antimony with manganese dioxide or after evaporation with sulphuric

acid.

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

A sample of alloy weighing 0.5 g is placed in a platinum Cup, add 20 cmof nitric acid (1:1), 1 cmhydrofluoric acid and dissolved by heating. After cooling the walls of the Cup and rinse with water, add 3 cmof concentrated sulfuric acid and the solution is evaporated prior to the allocation of white smoke of sulfuric acid. A Cup of cooled, rinse the walls of the Cup with water and repeat the evaporation of the solution prior to the allocation of white smoke of sulfuric acid two more times.

After cooling, dissolve the salt with heating in 20 cmof nitric acid (1:1), transfer the solution into a glass with a capacity of 250 cm, dilute with water to 10 cmand neutralized with ammonia until the appearance of turbidity does not disappear while mixing (pH 3 by universal indicator paper). Add 0.5 cmof concentrated nitric acid and further analysis are as indicated in claim 3.3.1

.

3.3.3. For alloys containing chromium

A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 250 cm, add 30−35 cmof the mixture of acids to dissolve, cover with a watch glass, a glass or plastic plate and dissolved by heating. After cooling, the hour glass or the plate and the side of the Cup then rinsed with water and evaporated the solution to dryness. The dry residue is dissolved in 20 cmof nitric acid (1:1) and evaporation repeated two more times, adding each time for 20 cmof nitric acid (1:1). The dry residue is dissolved in 20 cmof nitric acid (1:1), dilute with water to 100 cmand neutralized with ammonia until the appearance of turbidity does not disappear while mixing (pH 3 by universal indicator paper). Add 0.5 cmof concentrated nitric acid and further analysis are as indicated in claim 3.3.1

.

3.3.4. For alloys containing tungsten

A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 250 cm, 40−45 cm, addthe mixture of acids to dissolve, cover with a watch glass, a glass or plastic plate and dissolved by heating. The walls of the beaker and watch glass or plate rinse with water, add 5 cmof concentrated sulfuric acid and was boiled down to 10−12 cm. After cooling, the solution was added 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 is discarded, and the filtrate was neutralized with ammonia until the appearance of turbidity does not disappear while mixing (pH 3 by universal indicator paper). Add 0.5 cmof concentrated nitric acid and further analysis are as indicated in claim 3.3.1.

3.3.5. Construction of calibration curve

In a separating funnel with a capacity of 100−150 cmis injected 0,5; 1,0; 1,5; 2,0; 2,5 and 3,0 cmstandard solution B of antimony, diluted to 10 cmof hydrochloric acid (7:3). Add 1−3 drops of solution of tin dichloride and allowed to stand for 1 min. Add 1 cmof a solution of sodium attestatio and further analysis are as indicated in claim 3.3.1 in the determination of antimony in the alloy is less than 0.005%.

3.4. Processing of the results

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

,

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

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

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 as specified in clause 2.4.3.

3.4.4. Extraction-photometric method is used in case of disagreement in assessing the quality of Nickel and copper-Nickel alloys.

4. POLAROGRAPHIC METHODS FOR DETERMINATION OF ANTIMONY

4.1. The essence of the method

The method is based on preliminary separation of the antimony by coprecipitation with hydrated dioxide of manganese with subsequent polarographic determination of antimony in hydrochloric acid background.

When the mass fraction of antimony, less than 0.005%, the determination is carried out by Stripping voltammetry with a stationary mercury electrode. When the mass fraction of antimony in excess of 0.005% spend polarographic determination method of mercury dripping electrode.

4.2. Apparatus, reagents and solutions

Polarograph AC-PPT-1 or oscilloscope FOR polarograph-5122. Allowed the use of data handling other brands. The polarographic cell, with a capacity of 30−40 cm, made of glass, with external reference electrode (saturated calomel electrode) and with a stationary mercury electrode or dripping mercuric electrode.

The mercury film electrode (see drawing): the silver wire is soldered in a glass tube, naitanui part of the wire is polished to a Shine with a piece of silver and a polished end placed in a Cup with metallic mercury for 1 min. Emulgirovaniu electrode is removed from the mercury and carefully wiped with a clean piece of tracing paper or Teflon for uniform distribution of mercury over the surface of the metal. The electrode was washed thoroughly with water.

Nitrogen gas according to GOST 9293.

Mercury brands r0 according to GOST 4658, does not contain moisture and purified from the oxide film.

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

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

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 1:5.

Hydrofluoric acid according to GOST 10484.

Potassium permanganate according to GOST 20490, a solution of 40 g/DM.

Manganese sulfate according to GOST 435, a solution of 100 g/DM.

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

Ammonia water according to GOST 3760.

Potassium ferrocyanide according to GOST 4207, a solution of 30 g/DM.

Antimony brand Su0 according to GOST 1089.

Standard solutions of antimony

Solution a: 0.1 g of antimony is dissolved in 50 cmof concentrated sulfuric acid. The solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, made up to the mark with sulphuric acid (1:5) and stirred.

1 cmof the solution contains 0.0001 g of antimony.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, add 20 cmof concentrated hydrochloric acid, made up to the mark with water and mix: prepared immediately before the measurements.

1 cmof solution B contains from 0,00001 g

army.

4.3. Analysis

4.3.1. For alloys with a mass fraction of silicon is less than 0.1%, not containing chromium and tungsten

A sample of alloy weighing 1 g is placed in a beaker with a capacity of 250−300 cm, add 20 cmof nitric acid (1:1), cover with watch glass, glass or plastic plate and dissolved by heating. Boiling removes oxides of nitrogen, the solution was cooled, the walls of the beaker and watch glass or plate is then rinsed with water, diluted the solution with water up to 100−120 cmand add ammonia solution to pH 2 (universal indicator paper). Add 0.5 cmof concentrated nitric acid, 1 cmof solution of potassium permanganate, cover the beaker watch glass, glass or plastic plate and heat the solution nearly to boiling. Add 2cmof a solution of sulphate of manganese (in the analysis of alloys containing more than 0.5% of manganese, a solution of sulphate of manganese is not added), the solution was boiled for 2 min and left for 1 h.

The solution was filtered through a filter of medium density and repeatedly (10−12 times) washed with hot solution of nitric acid (1:100) until a negative reaction on copper (sample with solution of ferrocyanide of potassium).

The filter with the sediment was transferred to a beaker with a capacity of 250−300 cm, add 15 cmof concentrated sulfuric acid, 25 cmof concentrated nitric acid and evaporated until the appearance of dense white smoke of sulfuric acid.

In the case of the yellow color of the solution after evaporation add another 10 cmof concentrated nitric acid and repeat the evaporation. The operation of the evaporation with nitric acid is repeated until the disappearance of yellow color of the solution. The solution was evaporated to wet salts. Salt is dissolved at low heat in 20 cm3 mol/DMhydrochloric acid solution, add 1 g of hydrazine sulphate and boil for 2 minutes, the Solution was transferred to volumetric flask with a capacity of 50 cmand then filled to the mark 3 mol/DMsolution of hydrochloric

acid.

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

A sample of alloy weighing 1 g is placed in a platinum Cup, add 20 cmof nitric acid (1:1), 5 cmhydrofluoric acid and dissolved by heating. Cool the solution, rinse the walls of the Cup a small amount of water, add 3 cmof concentrated sulfuric acid and the solution is evaporated until the appearance of dense white smoke of sulfuric acid. The residue is cooled, rinse the walls of the Cup with a little water and repeat the evaporation of the solution until a white smoke of sulfuric acid.

Dissolve the salt by heating in 20 cmof nitric acid (1:1), transfer the solution into a glass with a capacity of 250 cm, dilute with water to 100−120 cmand further analysis are as indicated in claim 4.3.1.

4.3.3. For alloys containing chromium

A sample of alloy weighing 1 g is placed in a beaker with a capacity of 250−300 cm, 30−35 cm, addthe mixture of acids to dissolve, cover with a watch glass, a glass or plastic plate and dissolved by heating. After removal of oxides of nitrogen by boiling, cool the solution, rinse the glass or plate and the side of the Cup with a little water and evaporate the solution to dryness. The dry residue is dissolved in 20 cmof nitric acid (1:1) and again evaporate the solution to dryness. Operation of evaporation from 20 cmof nitric acid (1:1) is carried out three times, after which the dry residue is dissolved in 20 cmof nitric acid (1:1), dilute with water to 100−120 cmand lead further analysis as described in section 4.3.1.

4.3.4. For alloys containing tungsten

A sample of alloy weighing 1 g is placed in a beaker with a capacity of 250−300 cm, 40−45 cm and addthe mixture of acids to dissolve and dissolve when heated. To the obtained solution add 5 cmof concentrated sulfuric acid and was boiled down to 10−12 cm. The solution is diluted with 30 cmof water and filtered through double thick filter. The glass and the filter cake was washed 5−6 times with hot nitric acid (1:1). The rest of the filter is discarded. The solution was boiled down to 100−120 cmand lead further analysis as described in section 4.3.1.

In all cases, through the analysis of spend control experience.

4.3.5. Polarographic method

Aliquot part of the solution is 20 cmis placed in a polarographic cell with a dripping mercury electrode, the solution was degassed by nitrogen flow for 3−4 min, stop stirring and record the cathode polarogram from minus 0.1 to minus 0.5 In, registering a wave (peak) antimony recovery of about minus 0.25 V.

The sensitivity of the recording instrument is chosen so that the wave height (peak) of antimony recovery was less than 10 mm. When working with polarography-5122 polarogram shooting mode «differential.2» when the scan speed of 0.25 In/sec.

4.3.6. The method of Stripping voltammetry

Aliquot part 10, seehydrochloric acid solution is transferred to a polarographic cell with a stationary mercury electrode, the solution is degassed by a current of argon of 3−4 min, set at polarography voltage minus 0.4 V, and the electrolysis is carried out for 1−5 min while stirring the solution. At the end of electrolysis, stop stirring, allow the grout to settle down and record the anodic voltammogram from minus 0.5 to minus 0.05 V when linearly changing electrode potential, registering a peak of electrooxidation of antimony of about minus 0.2 V.

The sensitivity of the recording instrument and the time of electrolysis is chosen so that the peak height of antimony was not less than 10 mm.

The electrode is kept at a voltage of 0.05 V for 1 min in a continuous stirred solution, and then repeat the measurement.

When working with the electrode attached to the instrument PPT-1, after each measurement get a new drop of mercury.

4.3.7. Determination of antimony by the method of additions.

When polarographic determination of antimony of 0.1−0.5 cmof a standard solution And added into the solution, stir the solution for 2−3 minutes and polarographic as specified in clause 4.3.5.

In the determination of antimony by Stripping voltammetry method in 0.1−0.5 cmthe standard of a solution of antimony is added into the solution, stir the solution for 2−3 minutes and spend the definition, as stated in claim 4.3.6.

The amount of additives is chosen so that the height of the peak (wave) of antimony increased 2−3 times compared to the wave height (peak) of antimony for the test solution.

4.4. Processing of the results

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

,

where is the wave height (peak) of antimony for the test solution, mm;

wave height (peak) of antimony in a control experiment, mm.

 — concentration of standard solution, g/cm;

 — volume Supplement, cm;

wave height (peak) of antimony after the introduction of additives, mm;

 — weight of alloy, suitable aliquote part, taken on polarography,

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 and copper-Nickel alloys, approved under GOST 8.315, or by a method of additives, or a comparison of the results obtained for extraction-photometric or atomic absorption methods, in accordance with GOST 25086.

5. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF ANTIMONY (IN MASS FRACTION OF ANTIMONY FROM 0.001 TO 0.005%)

5.1. The essence of the method

The method is based on measuring the absorption of light by atoms of antimony, formed by the introduction of the analyzed solution in the flame acetylene-air after prior extraction of antimony by its coprecipitation with manganese dioxide.

5.2. Apparatus, reagents and solutions

Atomic absorption spectrometer with a radiation source for antimony.

Nitric acid according to GOST 4461, diluted 1:1, and a solution of 1.5 mol/DM.

Sulfuric acid according to GOST 4204, diluted 1:1, the solutions of 1.4 and 2.5 mol/DM.

Hydrochloric acid according to GOST 3118, solution 1 mol/DM.

Hydrofluoric acid according to GOST 10484.

Ammonia water according to GOST 3760.

Manganese nitrate according to NTD, a solution of 20 g/DM.

Potassium permanganate according to GOST 20490, a solution of 10 g/DM.

Hydrogen peroxide according to GOST 10929.

Antimony GOST 1089 with a mass fraction of antimony is not less than 99.9%.

Standard solutions of antimony.

Solution a: 0.25 g of antimony is dissolved by heating in 10 cmof sulphuric acid, the solution was cooled, transferred to a volumetric flask with a capacity of 500 cmand topped to the mark of 2.5 mol/DMsulfuric acid solution.

1 cmof the solution contains 0.0005 g of antimony.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cmand topped to the mark of 2.5 mol/DMsulfuric acid solution.

1 cmof solution B contains 0,00005 g

antimony.

5.3. Analysis

5.3.1. For alloys with a mass fraction of silicon to 0.05%

A sample of alloy weighing 2 g were placed in a glass with a capacity of 250 cmand dissolved by heating in 20 cmof nitric acid (1:1). Nitrogen oxides are removed by boiling and the solution diluted with water to a volume of 50 cm. Add 5 cmof a solution of nitrate of manganese, the solution is neutralized with ammonia until the appearance of the precipitate copper hydroxide, add 18 cmof nitric acid (1:1) and water to a volume of 90 cm. The solution is heated to boiling, add 10 cmof a solution of potassium permanganate, and boil for 2 min. after 30 min the precipitate was filtered off on a tight filter and washed the beaker and the precipitate 4−5 times a hot solution of 1.5 mol/DMnitric acid. The deployed filter is washed with water in a glass, which conducted the deposition, the filter is washed with 10 cmof hot sulfuric acid solution (1:4) containing few drops of hydrogen peroxide and then water. The washed filter is discarded and the solution was evaporated to wet salts. After cooling, add 8 cm1 mol/DMhydrochloric acid solution with mass fraction of antimony and 0.02% solution transferred to a volumetric flask or graduated tube with a capacity of 10 cm; the mass fraction of antimony in excess of 0.02% solution transferred to a volumetric flask with a capacity of 25 cmand topped to the mark of 1 mol/DMhydrochloric acid solution.

Measure the atomic absorption of antimony in the flame acetylene-air at a wavelength of 217,6 or the amount of 231.1 nm in parallel with the calibration of the races

torami.

5.3.2. For alloys with a mass fraction of silicon in excess of 0.05%

A portion of the alloy with a mass of 2 g is placed in a platinum Cup and dissolved by heating in 20 cmof nitric acid (1:1) and 2 cmhydrofluoric acid. After dissolution, add 10 cmsulphuric acid (1:1) and the solution was evaporated until a white smoke of sulfuric acid. The residue is cooled, rinse the walls of the Cup with water and evaporated again until a white smoke of sulfuric acid. The residue is cooled, the walls of the Cup rinse of 20 cm, the heated solution was transferred to a beaker with a capacity of 250 m, made up with water to a volume of 50 cm, add 5 cmof a solution of manganese nitrate and further analysis is carried out as specified in clause 5.3.1

.

5.3.3. Construction of calibration curve

In seven of eight glasses with a capacity of 250 cmis placed 0,4; 1,0; 2,0; 4,0; 6,0; 8,0 and 10.0 cmstandard solution B. In all the cups add water to a volume of 50 cm, add 5 cmof a solution of manganese nitrate and further analysis is carried out as specified in clause 5.3.1. According to the obtained results build a calibration curve.

5.4. Processing of the results

5.4.1. Mass fraction of antimony () in percent is calculated by the formula

,

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

 — the volume of the final solution, cm;

 — the weight of the portion of alloy,

5.4.2. 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.

5.4.3. 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 by additives or by comparison of the results obtained for extraction-photometric or polarographic methods in accordance with GOST 25086.