The volume of solution after dilution, see

The volume aliquote part of the solution, cm

The volume of solution after dilution, see

The volume aliquote part of the solution, cm

The volume of solution after dilution, see

The volume aliquote part of the solution, cm

Lead

From 0.001 to 0.002

Zinc

From 0.0015 to 0.002

Cadmium

From 0.001 to 0.002

0,0035

GOST 12362−79

Group B39

STATE STANDARD OF THE USSR


STEEL ALLOYED AND HIGH-ALLOYED

Methods for determination of trace antimony, lead,
tin, zinc and cadmium

Alloy and high-alloy steels. Methods for determination
of stibium, lead, tin, zinc and cadmium

Date of introduction 1981−01−01

APPROVED AND put INTO EFFECT by decision of the USSR State Committee for standards, dated 12 November 1979, No. 4289

Proven in 1985 by the Resolution of Gosstandart from 20.06.85 No. 1809 validity extended to 01.01.96*
___________________

* Expiration removed by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS No. 11−12, 1994). — Note the CODE.

REPLACE GOST 12362−66

REPRINT (December 1986, with Change No. 1, approved in June 1985 (IUS 9−85).


This standard specifies methods for the determination of antimony, lead, tin, zinc and cadmium in the alloy and high-alloy steels.

1. GENERAL REQUIREMENTS

General requirements for methods of analysis GOST 20560−81.

2. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF ANTIMONY (0,0002 — 0,01%) IN THE STEELS CONTAINING NOT MORE THAN 3% OF TUNGSTEN AND NOT MORE THAN 3% TITANIUM

2.1. The essence of the method

The method is based on reaction of interaction of the anion of antimony [with] a brilliant green in the medium of 1 M hydrochloric and 1 M sulfuric acid with the formation of the complex compound, painted in blue-green color is extracted with toluene. Measurement of light absorption of the extract is carried out at a = 640 nm.

2.2. Apparatus, reagents and solutions

Spectrophotometer, photoelectrocolorimeter, or spectropolarimeter.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77 and diluted 1:1 and 1:5.

Nitric acid GOST 4461−77 or GOST 11125−78 and diluted 1:1.

Sulfuric acid GOST 4204−77 or GOST 14262−78.

A mixture of hydrochloric and nitric acid (freshly prepared): to 150 cmof hydrochloric acid pour 50 cmof nitric acid and stirred.

Sodium atomistically according to GOST 4197−74, a solution of 100 g/DM.

Urea according to GOST 6691−77, saturated solution: 100 g of urea is placed in a beaker with a capacity of 250−300 cmand dissolved in 100 cmof water.

Tin chloride according to GOST 36−78, a solution of 250 g/lin hydrochloric acid, diluted 1:5.

Radio engineering carbonyl iron according to GOST 13610−79 or normative-technical documentation.

Diamond green, a solution of 5 g/DM: 0.5 g of brilliant green are dissolved in 100 cmof ethyl alcohol, diluted with water in the ratio 1:3.

Toluene according to GOST 5789−78.

Antimony brand Su00 according to GOST 1089−82.

Standard solutions of antimony.

Solution a: 0.05 g of antimony is dissolved in 25 cmof sulphuric acid when heated. The solution was cooled, poured another 25 cmof sulphuric acid, cautiously with continuous stirring the solution was transferred to a volumetric flask with a capacity of 500 cm, containing 300 cmof water, cooled, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of antimony.

Solution B: 5 cmstandard solution And transferred to a volumetric flask with a capacity of 50 cm, flow 30 cmwater, 5 cmof sulphuric acid with continuous stirring the solution is cooled, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of antimony.

The solution is prepared the day of use.

Solution: 5 cmstandard solution B is transferred to a volumetric flask with a capacity of 50 cm, flow 30 cmwater, 5 cmof sulphuric acid with continuous stirring the solution is cooled, made up to the mark with water, mix.

1 cmstandard solution contains 0,000001 g of antimony.

The solution is prepared the day of use.

(Changed red

action, Rev. No. 1).

2.3. Analysis

2.3.1. The weight of steel depending on the mass fraction of antimony is determined by the table. 1.

Table 1

The sample is placed in a beaker with a capacity of 250−300 cmor flask with a capacity of 250 cm, 30 cm, pour themixture of hydrochloric and nitric acids and 5 cmof sulfuric acid. Beaker cover watch glass, and dissolve a portion with a moderate heat. The solution was evaporated prior to the allocation of sulfuric acid vapor, is cooled.

When the mass fraction of antimony from from 0.0002 to 0.0025% to the contents of the glass poured 15 cmof hydrochloric acid (1:1), moderately heated to dissolve the salts, and cooled. The solution is poured from 1 to 5 cmof a solution of chloride of tin until full recovery of iron (III) from 2 to 5 cmof a solution of sodium attestatio to the enlightenment of the solution and establish unchanging its colour, let it sit 3 minutes, Then pour 1 cmof a saturated solution of urea, the solution was stirred and transferred to a separatory funnel with a capacity of 250 cm. The solution is poured with 50−60 cmof water, 15 drops of solution 5 g/lof brilliant green, 10 cmof toluene, after which the funnel and the solution vigorously shaken for 1 min. the Toluene and water layers are allowed to settle for 0.5 min, the aqueous layer discarded and the toluene is filtered off through cotton wool in a cuvette layer thickness of 10 mm and after 30 min, measure the optical density of the solution on the spectrophotometer at a = 640 nm or photoelectrocolorimeter with a filter having a region of transmittance in the range of wavelengths from 610 to 700 nm.

As a comparison, using a solution of toluene. Simultaneously conduct control experience for contamination of reagents.

The content of antimony found by the calibration schedule subject to amendments the reference experiment.

When the mass fraction of antimony in excess of 0.0025 to 0.01% of the weight of the sample after evaporation of sulfuric acid is dissolved in 15 cmof hydrochloric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 50 cm, made up with hydrochloric acid (1:1) to the mark and mix. Aliquot part of the solution (table. 1) is placed in a beaker and further analysis is carried out as described above.

(Changed edition, Rev. N 1).

2.3.2. Construction of calibration curve.

Six of cups (or flasks) with a capacity of 250−300 cmis placed 0.25 g of carbonyl iron. Five cups (or flasks) pour sequence 1, 2, 3, 5, 8 cmstandard solution, which corresponds to 0,000001; 0,000002; 0,000003; 0,000005; 0,000008 g of antimony. The sixth beaker (or flask) used for carrying out control of the experience. All glasses add 30 cmof a mixture of hydrochloric and nitric acids, 5 cmof sulfuric acid, cover glasses, watch glasses, and dissolve a portion with a moderate heat and evaporated to the start of allocation of steams of sulfuric acid. Further analysis is carried out as described in section 2.3.1.

From the values of absorbance of analyzed solutions is subtracted the value of optical density in the reference experiment. The found values of optical density and corresponding concentrations of antimony in building the calibration curve.

(Changed edition, Rev. N 1).

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;

the weight of steel, suitable aliquote part of the solution,

2.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 2.

Table 2

3. EXTRACTION-PHOTOMETRIC METHOD FOR THE DETERMINATION OF ANTIMONY (0,0005−0,01%) IN THE STEELS CONTAINING MORE THAN 3% OF TUNGSTEN AND MORE THAN 3% TITANIUM

3.1. The essence of the method

The method is based on reaction of interaction of the anion of antimony [] with methylene blue in the medium of 4 M sulfuric and 1 M hydrochloric acid with the formation of the complex compound, painted in blue, extracted with chloroform, or with a brilliant green in the medium of 1 M hydrochloric and 1 M sulfuric acid with the formation of the complex compound, painted in blue-green color is extracted with toluene. Maximum light absorption of the solution is observed when = 655 nm or = 640 nm, respectively.

Antimony pre-separated from interfering elements by precipitation as a sulfide by thioacetamide in 0.5 M hydrochloric acid solution in the presence of tartaric acid using as a collector of mercury sulphide.

3.2. Apparatus, reagents and solutions

Spectrophotometer, spectrophotometer, photoelectrocolorimeter.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77.

Nitric acid GOST 4461−77 or GOST 11125−78.

Sulfuric acid GOST 4204−77 or GOST 14262−78.

Orthophosphoric acid according to GOST 6552−80.

A mixture of hydrochloric and nitric acids is freshly prepared (to 150 cmof hydrochloric acid pour 50 cmof nitric acid and stirred) and diluted 1:1.

Tartaric acid according to GOST 5817−77, a solution of 500 g/DM.

Ammonia water according to GOST 3760−79.

Ammonium radamisty, a solution of 50 g/DM.

Mercury nitrate (oxide) according to GOST 4520−78, a solution of 10 g/DM: 1 g of nitrate of mercury dissolved in 80 cmof water containing 5 cmof nitric acid. The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

The thioacetamide aqueous solution of 20 g/DM.

Sodium atomistically according to GOST 4197−74, a solution of 100 g/DM.

Urea according to GOST 6691−77, saturated solution: 100 g of urea is placed in a beaker with a capacity of 250−300 cmand dissolved in 100 cmof water.

Tin chloride according to GOST 36−78, a solution of 250 g/lin hydrochloric acid, diluted 1:5.

Hydroxylamine hydrochloric acid according to GOST 5456−79.

Diamond green, a solution of 5 g/DM: 0.5 g of brilliant green are dissolved in 100 cmof ethyl alcohol, diluted in the ratio 1:3.

Methylene blue aqueous solution 1 g/DM.

Chloroform according to GOST 20015−74.

Toluene according to GOST 5789−78.

Antimony brand Su00 according to GOST 1089−82.

Standard solutions of antimony.

Solution a: 0.05 g of antimony is dissolved in 25 cmof sulfuric acid. After dissolution of the sample poured another 25 cmof sulfuric acid solution cautiously with continuous stirring poured into a volumetric flask with a capacity of 500 cm, containing 300 cmof water, cooled, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of antimony.

Solution B: 5 cmstandard solution And transferred to a volumetric flask with a capacity of 50 cm, flow 30 cmwater, 5 cmof sulphuric acid with continuous stirring the solution is cooled, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of antimony.

Solution: 5 cmstandard solution B is transferred to a volumetric flask with a capacity of 50 cm, flow 30 cmwater, 5 cmof sulphuric acid with continuous stirring the solution is cooled, made up to the mark with water, mix.

1 cmstandard solution contains 0,000001 g of antimony.

The solution is prepared the day of use.

Universal indicator paper.

(Changed edition, Rev. N 1).

3.3. Analysis

3.3.1. The weight of steel depending on the mass fraction of antimony is determined by the table. 3.

Table 3

Placed in a glass or flask with a capacity of 250−300 cm, 30 cm, pour themixture of hydrochloric and nitric acids, 5 cmof sulphuric acid, the beaker cover watch glass, and dissolve a portion with a moderate heat. The solution was evaporated prior to the allocation of sulfuric acid vapor, is cooled. The contents of the glass pour 50 cmof water, 15−20 cmsolution, 500 g/lof tartaric acid and heat the solution for 10 min to dissolve the salts. Adding 20−30 cmof ammonia solution to obtain pH 8−9 and heated to dissolution of tungsten acid. The solution is poured hydrochloric acid to pH 2 by universal indicator and the excess 7.5 cm. Solution top up with water to 150 cmand heated to boiling.

Carefully add 1−2 g of hydroxylamine hydrochloric acid and boil the solution until complete reduction of iron (by the reaction with ammonium radamisty).

Add 10 cmof a solution of thioacetamide, the solution is kept at 90−95°C for 10 min, add 1 cmof a solution of 10 g/DMof nitrate of mercury and after 10 minutes add another 10 cmof a solution of thioacetamide. The solution with precipitated sediment sulphide maintained at 85−90°C for 30−40 min and cooled. After 2 h, the precipitate filtered off sulphides in two medium density filter (white ribbon), washed 6−7 times with water. The filtrate is discarded. The filter cake was dissolved in three portions (10−15 cm) of a hot mixture of hydrochloric and nitric acids (1:1), collecting the solution in a beaker or flask, which carried out the deposition of sulphides. The filter was washed 3−4 times with hot water, adding the wash liquid to the main filtrate. Further analysis is carried out, as indicated in the claims. 3.3.1.1 or 3.3.1.2.

(Changed edition, Rev. No. 1).

3.3.1.1. Definition of antimony with methylene blue.

To the filtrate poured 6 cmof sulfuric acid, cover the beaker or the flask with a watch glass, and evaporate the solution until the appearance of sulphuric acid fumes and cooled.

The contents of the beaker or flask pour 6 cmof water, heated to dissolve the salts, pour 3 cmof hydrochloric acid. The solution was cooled, poured 1 cmof a solution of chloride of tin, mix. Then add 3 cmof a solution of sodium attestatio and, periodically stirring the solution, allow the solution to stand for 3 min. Pour 1 cmof a saturated urea solution, 1 cmof phosphoric acid, mix the solution and transfer it into separating funnel capacity of 250 cm. To the solution poured water up to 30 m of its volume, 0.5 cmof a solution of methylene blue, 30 cmof chloroform, after which the funnel is vigorously shaken for 1 min. Chloroform and water layers are allowed to settle for 0.5 min. the Chloroform layer was filtered through cotton wool, transferred to a cuvette layer thickness of 10 mm and measure the optical density of the solution on the spectrophotometer at a = 655 nm or photoelectrocolorimeter with a filter having a region of transmittance in the range of wavelengths from 610 to 700 nm. As a solution the comparison used the chloroform. The content of antimony found by the calibration schedule subject to amendments the reference experiment.

(Changed edition, Rev. No. 1).

3.3.1.2. Determination of antimony with brilliant green.

To the filtrate poured 5 cmof sulfuric acid, cover the beaker watch glass, and evaporate the solution to start the selection of vapors of sulfuric acid and cooled. Further analysis is performed as described in section 2.3.1. For the mass concentration of antimony greater than 0.001 to 0.01% of the weight of steel after evaporation of sulfuric acid is dissolved in 15 cmof hydrochloric acid (1:1), the solution transferred to a volumetric flask with a capacity of 50 cm, made up with hydrochloric acid (1:1) to the mark, mix and take aliquot part of the solution was 10 cm. Further analysis is carried out as specified in clause 2.3.

(Changed edition, Rev. No. 1).

3.3.2. Construction of calibration graphs

3.3.2.1. Construction of calibration curve in the determination of antimony with methylene blue.

Six glasses or flasks with a capacity of 250−300 cmis placed 0.5 g of carbonyl iron. Five beakers or flasks poured consistently 0,2; 0,5; 1; 1,5; 2 cmstandard solution B, which corresponds to the 0,000002; 0,000005; 0,000010; 0,000015; 0,00002 g of antimony. The sixth beaker or flask serves for the control experience. All the glasses are poured at 30 cmof a mixture of hydrochloric and nitric acids, 5 cmof sulfuric acid, cover glasses, watch glasses, heated to full dissolution of carbonyl iron, is evaporated until the appearance of sulphuric acid fumes and cooled. To the content of the beaker was added 50 cmwater, 10 cmof a solution of tartaric acid and heat the solution for 10 minutes Further analysis performed as described in the claims. 3.3.1 and 3.3.1.1.

From the values of absorbance of analyzed solutions is subtracted the value of optical density in the reference experiment.

On the found values of optical density and corresponding concentrations of antimony in building the calibration curve.

3.3.2.2. Construction of calibration curve in the determination of antimony with brilliant green.

Six glasses or flasks with a capacity of 250−300 cmis placed 0.5 g of carbonyl iron. Five beakers or flasks poured successively 2, 3, 4, 5, 6 cmstandard solution, which corresponds to the 0,000002; 0,000003; 0,000004; 0,000005; 0,000006 g of antimony. The sixth beaker or flask serves for the control experience. All beakers or flasks go for 30 cmof a mixture of hydrochloric and nitric acids, 5 ml of sulfuric acid, cover glasses, watch glasses, heated to full dissolution of carbonyl iron, is evaporated until the appearance of sulphuric acid fumes and cooled. The contents of the beaker or flask poured approximately 50 cmwater, 10 cmsolution, 500 g/lof tartaric acid and heat the solution for 10 min.

Further analysis is carried out, as indicated in the claims. 3.3.1 and 3.3.1.2.

From the values of absorbance of analyzed solutions is subtracted the value of optical density in the reference experiment. On the found values of optical density and corresponding concentrations of antimony in building the calibration curve.

3.3.2.1, 3.3.2.2. (Changed edition, Rev. No. 1).

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;

the weight of steel,

3.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 4.

Table 4

4. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF LEAD (0,0005−0,01%)

4.1. The essence of the method

The method is based on the formation in a slightly alkaline environment (pH of 11.5) in the presence of potassium cyanide chelation of lead with dithizone, painted in red color and extracted with chloroform. Maximum light absorption of the solution is observed at a = 520 nm. Lead pre-separated from the deformity of the elements by precipitation as a sulfide by thioacetamide in ammoniacal solution (pH 7.5) in the presence of tartaric acid as complexing agents.

4.2. Apparatus, reagents and solutions

Spectrophotometer, photoelectrocolorimeter, or spectropolarimeter.

a pH meter.

Thermometer.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77 and diluted 1:1.

Nitric acid GOST 4461−77 or GOST 11125−78 diluted 1:1, 1:100.

A mixture of hydrochloric and nitric acids, freshly prepared (150 ml hydrochloric acid pour 50 cmof nitric acid, stirred) and diluted 1:1.

Tartaric acid according to GOST 5817−77, a solution of 500 g/DM.

Ammonia water according to GOST 3760−79 and diluted 1:1, 1:100, 1:200.

Potassium cyanide, solution 100 g/DM.

Buffer solution (pH 11,5): 10 cmsolution 100 g/lof potassium cyanide poured 7.5 cmof ammonia solution and add water to 100 cm.

Radio engineering carbonyl iron according to GOST 13610−79 or normative-technical documentation.

Copper grade MO according to GOST 859−78 (ST SEV 206−75), a solution of 10 g/DM: 1 g of copper metal is dissolved in 20−25 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of copper.

The thioacetamide aqueous solution of 20 g/DM.

Ammonium neccersarily according to GOST 20478−75, a solution of 25 g per 100 cm.

Iron nitrate according to GOST 4111−74, 1% solution: 1 g of iron nitrate were placed in a glass with a capacity of 100 cm, is dissolved in 50 cmof water, pour 5 cmof nitric acid, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Chloroform according to GOST 20015−74 distilled at 61 °C.

Ditson according to GOST 10165−79, 0,04% solution in chloroform: 40 mg dithizone placed in a beaker with a capacity of 100 cmand dissolved in 50 cmof chloroform. Solution dithizone in chloroform is transferred to a separatory funnel with a capacity of 200 cmand stirred with 200 cm(in portions of 50 cm) ammonia solution (1:100).

Ditson passes into the aqueous ammonia layer and the oxidation products remain in the chloroform layer discarded. The solutions are combined and placed in a separating funnel with a capacity of 500 cm, is poured dropwise with hydrochloric acid (1:1) to pH 4−5 by universal indicator, add 100 cmof chloroform.

The solution in the separating funnel shaken for 1 min.

The chloroform layer is drained into another separatory funnel with a capacity of 500 cmand washed three times with water. The resulting solution of dithizone in chloroform was filtered through dry cotton wool and stored in a flask made of dark glass in a cool place.

Ditson, 0,01% solution in chloroform (dishwashing and reagents): 25 cm0,04% solution of dithizone transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with chloroform and mix.

Ditson, 0,002% solution in chloroform: 5 cm0,04% solution of dithizone transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with chloroform and mix.

Hydroxylamine hydrochloric acid according to GOST 5456−79, a solution of 40 g/DM, purified dithizone: 300 cm1% solution of hydrochloric acid hydroxylamine was placed in a separating funnel with a capacity of 500 cm, add drop by drop ammonia solution to pH 6−7 by universal indicator and shake successively with several portions of 10 cmof 0.01% solution in chloroform dithizone up until the last portion of dithizone will have a dark green color. Excess dithizone extracted with chloroform until, until the last portion of the chloroform becomes colorless.

Sodium citrate according to GOST 22280−76, a solution of 100 g/DM, purified dithizone: 300 cmsolution 100 g/lof sodium citrate is placed in a separating funnel with a capacity of 500 cmand shaken successively with several portions of 10 ml of 0.01% solution in chloroform dithizone up until the last portion of dithizone will have a dark green color.

Excess dithizone extracted with chloroform until, until the last portion of the chloroform becomes colorless.

Thymol blue, aqueous solution: 0.1 g of thymol blue was placed in a beaker with a capacity of 100 cm, is dissolved in 50 cmof water, transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.

Universal indicator paper.

Lead brand WITH GOST 3778−77 (ST SEV 142−75).

Standard solutions of lead.

Solution a: 0.1 g of lead dissolved in 30 ml of nitric acid under heating. The resulting solution was transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 0.0001 g of lead.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 ml, poured 10 cmof nitric acid (1:1), made up to the mark with water and mix.

1 cmof solution B has the 0.00001 g of lead.

Solution: 10 ml solution B is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof nitric acid (1:1), made up to the mark with water and mix.

1 cmof the solution contains 0,000001 g of lead.

Solution prepared on the day of use.

(Changed edition, Rev. No. 1),

4.3. Analysis

4.3.1. The weight of steel depending on the mass fraction of lead is determined by the table. 5.

Table 5

The sample is placed in a beaker with a capacity of 250−300 cmor flask with a capacity of 250 cm, 20−25 cm pouredhydrochloric acid, 7−8 cmof nitric acid, cover with watch glass and dissolved under heating.

The solution was evaporated to wet salts, poured 5cmof hydrochloric acid and heat the contents of the beaker to dissolve the salts. Add 30 cmof water, 15−20 cmof tartaric acid solution, 1 cmof a solution of copper nitrate and heated for 5 min.

The solution was cooled, poured 20−25 cmof ammonia solution and again heat for 5−8 min, Set pH 7.5 with hydrochloric acid (1:1) using pH meter. Dilute the solution with water to 150 cm, heated to 85−90°C, pour 10 cmof a solution of thioacetamide and incubated for 10 min at the same temperature. Newly poured 10 cmof a solution of thioacetamide solution and leave to precipitate for 2 h at 40−50°C. the Precipitate is filtered off sulphides in two medium density filter (white ribbon), washed 7−8 times with cold water. The filtrate is discarded. The filter cake was dissolved in 40−50 cm(chunks 10 cm) of a hot mixture of hydrochloric and nitric acids (1:1) and washed the filter 2−3 times with hot water collecting the filtrate and washings in a beaker, which made the deposition. The solution was evaporated to dryness, poured 3−5 cmof nitric acid and heat the contents of the beaker to dissolve the salts. The solution is poured 70−100 cmof water, 20 cmof naternicola solution of ammonia and boiled for 10−15 min. Then poured 1 ml of a solution of nitrate of iron, solution of ammonia until the appearance of stable hydroxide precipitate, and the excess ammonia 0.5−1 cm.

The precipitate was filtered off on a medium density filter (white ribbon) and washed 8−10 times with a hot solution of ammonia, diluted 1:200. The filter cake is dissolved in 5 cmof hot nitric acid (1:1), the filter was washed 7−8 times with hot water collecting the filtrate and washings in a beaker, in which was conducted the deposition.

For the mass concentration of lead in the steel in excess of 0.0005 to 0.001%, the solution was evaporated to dryness, the salt was dissolved in 1 ml of nitric acid (1:1) under heating. The solution was cooled, transferred to 10 cmof water in a separating funnel with a capacity of 100 cm.

For the mass concentration of lead in more than 0.001 to 0.01% solution transferred to a volumetric flask with a capacity of 50 cm, cooled, made up to the mark with water and mix. Aliquot part of the solution (table. 5) is placed in a separating funnel with a capacity of 100 cmand pour 5 cmof nitric acid (1:100).

To the contents of the separating funnel pour 2 cmof a solution of sodium citrate, 1 cmof a solution of hydrochloric acid hydroxylamine and three drops of thymol blue solution.

Neutralized with ammonia solution until the color of the indicator from pink to blue (pH of 9.5). Then pour the 2 cmbuffer solution (pH 11,5), mix, add 10 cm0,002% solution of dithizone (from burette) and shaken for 1 min. Aqueous and chloroform layers allowed to settle and decanted chloroform layer in a dry cuvette with a layer thickness of 10 mm. after 10 min the optical density of the solution measured on a spectrophotometer at a = 520 nm or photoelectrocolorimeter with a filter having a region of transmittance in the wavelength interval from 480 to 540 nm. As a comparison, using a solution of chloroform.

The lead content found by the calibration graph with wher

the incident control experience.

4.3.2. Construction of calibration curve.

Six glasses with a capacity of 250−300 cmor flasks with a capacity of 250 cmis placed 0.5 g of carbonyl iron.

Five beakers or flasks poured successively 4, 6, 8, 10, 12 cmstandard solution, which corresponds to 0,000004; 0,000006; 0,000008; 0,00001; 0,000012 g lead. The sixth beaker or flask serves for the control experience. All beakers or flasks add 20−25 cmof hydrochloric acid, 7−8 cmof nitric acid. Glasses cover watch glass and heated until complete dissolution of the sample.

Further analysis is carried out as described in 4. 3.1.

From the values of absorbance of analyzed solutions is subtracted the value of optical density in the reference experiment.

On the found values of optical density of the solutions and their corresponding values of lead concentrations to build a calibration curve.

4.3.1, 4.3.2. (Changed edition, Rev. No. 1).

4.4. Processing of the results

4.4.1. Mass fraction of lead (a) percentage calculated by the formula

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

the weight of steel, suitable aliquote part of the solution,

4.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 6.

Table 6

5. POLAROGRAPHIC METHOD FOR DETERMINING LEAD (0,001−0,01%)

5.1. The essence of the method

The method is based on the ability of the lead to recover on dripping mercuric electrode at a potential of minus 0.54 In the peak relative to the mercury anode in the background of 1 M citric acid. Mode polarography — AC or oscilloscope. Lead pre-separated from the main components with thioacetamide in the presence of tartaric acid with a pH of 7.5.

5.2. Apparatus, reagents and solutions

Polarograph AC or polarograph oscilloscope.

The polarographic cell, made of glass with anode (bottom mercury) and mercury-drip cathode attached to polarography.

Thermometer.

a pH meter.

Mercury brands r0 or R1 according to GOST 4658−73 that does not contain moisture.

The gaseous nitrogen according to GOST 9293−74 or argon according to GOST 10157−79.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77 and diluted 1:1.

Nitric acid GOST 4461−77 or GOST 11125−78.

Perchloric acid, a solution of 570 g/DM.

Tartaric acid (tartaric) according to GOST 5817−77.

Citric acid according to GOST 3652−69, a solution of 500 g/DM.

A mixture of hydrochloric and nitric acid (freshly prepared): to 400 cmwater flow of 300 cmof hydrochloric acid and 100 cmof nitric acid with stirring.

Ammonia water according to GOST 3760−79.

Mercury nitrate the oxide according to GOST 4520−78, a solution of 10 g/DM.

The thioacetamide aqueous solution of 20 g/DM.

Lead brand WITH GOST 3778−77 (ST SEV 142−75).

Standard solutions of lead.

Solution a: 0.1 g of lead is dissolved by heating in 30 cmof nitric acid. The resulting solution was transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 0.0001 g of lead.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 2 cmof hydrochloric acid, made up to the mark with water and mix.

1 cmof solution B has the 0.00001 g of lead.

Solution B is prepared on the day of use.

(Changed edition, Rev. No. 1).

5.3. Analysis

5.3.1. A sample of steel weighing 0.5 g were placed in a glass with a capacity of 250−300 cmor flask with a capacity of 250 cm, flow 15 cmof hydrochloric acid and 5 cmof nitric acid, cover with watch glass and dissolve the sample when heated. The solution was evaporated to wet salts, poured 5cmof hydrochloric acid and heat the contents of the beaker to dissolve the salts. Add 30 cmof water, 15−20 cmof tartaric acid, 1 cmof solution of nitrate of mercury and heated for 5 min. the resulting solution was cooled, poured 20−25 cmof ammonia solution and heated again for 5 min, Set pH to 7.5 with hydrochloric acid (1:1) using pH meter. Dilute the solution with water to 150 cm, heated to 90 °C, pour 10 cmof a solution of thioacetamide and incubated for 10 min at the same temperature. Newly poured 10 cmof a solution of thioacetamide solution and leave to precipitate for 2 h at 40−50°C. the Precipitate is filtered off sulphides in two medium density filter (white ribbon), washed 7−8 times with cold water. The filtrate is discarded. The filter cake was dissolved in 40−50 cm(chunks 10 cm) of a hot mixture of hydrochloric and nitric acids and the filter was washed 2−3 times with hot water collecting the filtrate and washings in a beaker, which made the deposition. Pour 3 cmof perchloric acid and evaporated to moist salts. Salt is dissolved by heating in 19 cmof a solution of citric acid, the solution transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

To remove oxygen from the analyzed solution through latest blow nitrogen or argon for 5 min and remove polarogram from minus 0.2 to minus 0.8 V, recording the peak recovery of the lead at minus of 0.54 V. the Sensitivity of the device is chosen so that the height of the peak recovery of lead was not less than 10 mm.

Lead find graduirovannam

mu schedule.

5.3.2. Construction of calibration curve.

In beakers or flasks with a capacity of 250−300 cmis placed consistently: 0,5; 1; 3; 4; 5 cmstandard solution B, which corresponds to 0,000005; 0,00001; 0,00003; 0,00004; 0,00005 g lead, poured in 15 cmof hydrochloric acid and 5 cmof nitric acid and then the solutions is carried out through all stages of analysis, as specified in clause 5.3.1.

At the same time spend control experience.

Calculate the difference of the heights of peaks of the studied solution and the reference experiment.

5.3.1, 5.3.2. (Changed edition, Rev. No. 1).

5.4. Processing of the results

5.4.1. Mass fraction of lead (a) percentage calculated by the formula

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

the weight of steel,

5.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 7.

Table 7

6. INVERSION-VOLTAMMETRIC METHOD FOR DETERMINATION OF LEAD (0,0002−0,01%)

6.1. The essence of the method

The method is based on the preconcetration of lead on stationary mercury drop electrode at a potential of minus 0.85 and In the solution 200 g/lof citric acid and a solution of 60 g/lof ammonium chloride with the subsequent registration of the current of anodic dissolution of lead at a potential of minus of 0.48 In relative to silver chloride electrode in the presence of the main components of steel.

6.2. Apparatus, reagents and solutions

Polarograph AC or polarograph oscilloscope.

Cell with a remote anode (mercury in a saturated solution of potassium chloride), silver chloride reference electrode and a stationary mercury drop electrode attached to polarography.

Mercury GOST 4658−73 brand RO that does not contain moisture.

The gaseous nitrogen according to GOST 9293−74 or argon according to GOST 10157−79.

Hydrochloric acid according to GOST 14261−77.

Nitric acid according to GOST 11125−78.

Hydrofluoric acid (hydrofluoric acid) according to GOST 10484−78, a solution of 400 g/DM.

Citric acid according to GOST 3652−69 (ST SEV 394−76).

Ammonium chloride according to GOST 3773−72.

Background for polarographically containing 200 g/lof citric acid and 60 g/DMammonium chloride.

Ascorbic acid according to GOST 4815−76.

Potassium chloride according to GOST 4234−77, saturated solution.

Water bidistilled.

Lead brand WITH GOST 3778−77 (ST SEV 142−75).

Standard solutions of lead.

Solutions A and B (see section 5.2).

Solution: 5 cmof solution B is placed in a volumetric flask with a capacity of 50 cm, add 1 cmof hydrochloric acid, made up to the mark with water and mix.

1 cmof the solution contains 0,000001 g of lead.

Solutions B and C prepared on the day of use.

(Changed edition, Rev. No. 1)

.

6.3. Analysis

6.3.1. A sample of steel weighing 0.5 g were placed in a glass with a capacity of 250−300 cmor flask with a capacity of 250 cm, add 15 cmof hydrochloric acid and 5 cmof nitric acid and dissolve the sample when heated. The solution was evaporated to wet salts, poured 5cmof hydrochloric acid, and again evaporated to moist salts. This operation is repeated twice.

Salt dissolved in 5 cmof hydrochloric acid. In the determination of lead in steels containing tungsten, molybdenum, titanium and niobium, the contents of the beaker transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix. In the determination of lead in steels containing tungsten, molybdenum, titanium and niobium, the contents of the beaker quantitatively transferred to a platinum Cup or a Cup of glassy carbon or Teflon beaker, add 3 cmhydrofluoric acid and heated until complete dissolution of the precipitate of tungsten and molybdenum acid, and hydrolysis products of titanium and niobium. The solution was cooled, transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water, mixed and immediately placed in a plastic or Teflon container and lid.

To determine the content of lead in the polarographic cell is filled 20 cmof the background electrolyte, previously purged with nitrogen or argon for 5 min, add in accordance with the table. 8 aliquot part of the investigated solution, depending on the mass fraction of lead in steel is approximately 0.01−0.02 g of ascorbic acid.

Table 8

Set on polarography potential of minus 0.85 and In and carried out the concentration of lead on a stationary mercury drop electrode in a continuously stirred solution over 2−3 min. At the end of the accumulation time, stop stirring and allow solution to settle down 15, and then remove the anodic polarization curve with linearly varying electrode potential of minus 0.85 to minus 0.2 V, registering a peak of dissolution of the lead at minus of 0.48 V. the Sensitivity of the device is chosen so that the height of the recorded peak was at least 10 mm. For each dimension, get a new drop of mercury.

(Changed edition, Rev. No. 1).

6.3.2. Lead find by the method of standard additions. Aliquot part of the standard solution (see section 6.3.1) is added to polarographically the solution was stirred for 1 min and further analysis are as under determination of lead in test solution.

The value of the standard additives is chosen so that the peak height of lead after introduction of the additive increased 1.5−2 times.

6.4. Processing of the results

6.4.1. Mass fraction of lead (a) percentage calculated by the formula

where is the peak height of lead in polarography of test solution, mm;

the peak height of lead in polarography solution in the reference experiment, mm.

the peak height of lead after introduction into a cell of standard addition, mm;

 — the volume of standard addition, cm;

 — concentration of standard solution, g/cm;

the weight of steel, suitable aliquote part of the solution

G.

6.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 9.

Table 9

7. FLAMELESS ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF LEAD (0,0002−0,01%)

7.1. The essence of the method

The method is based on measuring absorption of radiation by free atoms of lead in = is 283.3 nm, formed with the introduction of the analyzed solution into the graphite cuvette. Lead pre-separated from the deformity of the elements by precipitation as a sulfide by thioacetamide in ammoniacal solution (pH 7.5) in the presence of tartaric acid as complexing agents.

7.2. Equipment, reagents, solutions

Atomic absorption spectrophotometer with graphite cuvette.

Lamp for determination of lead.

Cylinder with high-purity argon.

a pH meter.

Thermometer.

Water bidistilled.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77.

Nitric acid GOST 4461−77 or GOST 11125−78 and diluted 1:1.

A mixture of hydrochloric and nitric acids is freshly prepared (to 150 cmof hydrochloric acid add 50 cmof nitric acid, stirred) and diluted 1:1.

Tartaric acid according to GOST 5817−77, a solution of 500 g/DM.

Ammonia water according to GOST 3760−79.

The thioacetamide aqueous solution of 20 g/DM.

Copper grade MO according to GOST 859−78 (ST SEV 206−75), a solution of 10 g/DM: 1 g of copper metal is dissolved by heating in 15−20 cmof nitric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of copper.

Radio engineering carbonyl iron according to GOST 13610−79 or normative-technical documentation.

Lead brand WITH GOST 3778−77 (ST SEV 142−75).

Standard solutions of lead.

Solution a: 0.1 g of lead dissolved in 30 cmof nitric acid, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 0.0001 g of lead.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 10 cmof nitric acid, made up to the mark with water and mix.

1 cmof solution B has the 0.00001 g of lead.

Solution: 10 cmof solution B is placed in a volumetric flask with a capacity of 100 ml, add 10 cmof nitric acid, made up to the mark with water and mix.

1 cmstandard solution contains 0,000001 g of lead.

The solution is prepared the day of use.

(Changed edition, Rev. No. 1).

7.3. Analysis

7.3.1. The weight of steel depending on the mass fraction of lead is determined by the table. 10.

Table 10

The sample is placed in a beaker with a capacity of 250−300 cmor flask with a capacity of 250 cm, 30 cm, pour themixture of hydrochloric and nitric acids, cover the watch glass and dissolve the sample when heated. The solution was evaporated to a volume of 7−10 cmadd 30 cmof water, 20 cmof a solution of tartaric acid and heated for 5 min.

To the solution was added 1 cmof copper solution, pour the 20−25 cmof a solution of ammonia to pH 8−10, and again heated for 5−10 minutes, cool and set on pH-meter pH 7.5 with hydrochloric acid (1:1). The solution is diluted with water to 150 cm, heated to 85−90°C, pour 10 cmof a solution of thioacetamide and incubated for 10 min at the same temperature. Newly poured 10 cmof a solution of thioacetamide solution and leave to precipitate for 2 h at 40−50°C. the Precipitate is filtered off sulphides in two medium density filter (white ribbon), washed 7−8 times with cold water. The filtrate is discarded. The filter cake was dissolved in 40−50 cm(in portions of 10 ml) hot mixture of hydrochloric and nitric acids (1:1) and washed the filter 2−3 times with hot water collecting the filtrate and washings in a beaker, in which was conducted the deposition. The filter is discarded, the solution twice evaporated to wet salts, adding each time 5 cmof nitric acid. Salts dissolved in 4 cmof nitric acid when heated, add 5−10 cmof water, the solution transferred to a volumetric flask (see table 10), made up to the mark with water and mix. Pipetted 20 µl of the resulting solution, inject it into the graphite cuvette to measure the absorption of radiation by free atoms of lead in = is 283.3 nm.

The lead content found by the calibration graph with amendments, the control

wow experience.

7.3.2. Preparing the appliance for measurement.

Activation of the device, setting the spectrophotometer at a resonance radiation at = is 283.3 nm, adjustment control unit, block, atomization is carried out according to the instructions supplied with the device.

Conditions for determination of lead:

The analytical line is 283.3 nm

The spectral slit width of 0.7 nm

Operating current of the lamp 25 And

Drying time at 100 °C — 10

The decomposition at 700 °C — 10

Time atomization at 2100 °C — 10 s.

7.3.3. Construction of calibration curve

Six glasses with a capacity of 250−300 cmor flasks with a capacity of 250 cmis placed 0.5 g of carbonyl iron. In five glasses poured the sequence 1; 3; 5; 7; 10 cmstandard solution, which corresponds to 0,000001; 0,000003; 0,000005; 0,000007; 0,00001 g of lead. The sixth beaker or flask serves for the control experience. All beakers or flasks go for 30 cmof a mixture of hydrochloric and nitric acid, cover with watch glass and dissolve the sample when heated. The solutions were evaporated to a volume of 7−10 cm, poured in 30 cmof water, 20 cmof a solution of tartaric acid and heated for 5 minutes Further analysis performed as described in section 7.3.1 except that the solutions after the salts dissolved in 4 ml of nitric acid, transferred to volumetric flasks with a capacity of 25 cm. The solutions were made up to the marks with water, stirred, taken by pipette 20 µl of each solution was injected it into a graphite cuvette and measure the absorption of radiation by free atoms when = is 283.3 nm. From the values of absorbance of analyzed solutions is subtracted the value of optical density in the reference experiment. The found values of optical density and corresponding values of the lead concentrations to build a calibration graph

IR.

7.3.1, 7.3.2. (Changed edition, Rev. No. 1).

7.4. Processing of the results

7.4.1. Mass fraction of lead (a) percentage calculated by the formula

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

the weight of steel, g;

25 — volume of a standard solution of lead used to build the calibration curve, cm;

 — volume of test solution became, after dilution, see.

7.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 11

Table 11

(Changed edition, Rev. 1).

8. POLAROGRAPHIC METHOD FOR THE DETERMINATION OF TIN (0,001−0,01%) IN THE STEELS CONTAINING NIOBIUM AND TITANIUM

8.1. The essence of the method

The method is based on the ability to recover tin on dripping mercuric electrode at a potential of minus peak of 0.48 In a relatively mercury anode in the background of 1 M hydrochloric acid and 4 M ammonium chloride. Mode polarographically AC or oscilloscope. Tin is pre-separated from the main components of steel in hydroxide beryllia in the presence of Trilon B.

8.2. Apparatus, reagents and solutions

Polarograph AC or polarograph oscilloscope.

The polarographic cell, made of glass with anode (bottom mercury) and mercury-drip cathode attached to polarography.

The mercury brand of RO or R1 according to GOST 4658−73 that does not contain moisture.

The gaseous nitrogen according to GOST 9293−74 or argon according to GOST 10157−79.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77.

Nitric acid GOST 4461−77 or GOST 11125−78.

Sulfuric acid GOST 4204−77 or GOST 14262−78 and 3.5 M, and diluted 1:4.

Ammonia water according to GOST 3760−79 and diluted 1:50.

Ammonium chloride according to GOST 3773−72.

Beryllium nitrate, an aqueous solution of 8 g per 100 cm.

Salt is the disodium Ethylenediamine--tetraoxane acid, 2-water (Trilon B), according to GOST 10652−73, a solution of 100 g/DM.

Tin GOST 860−75 stamps O1.

Standard solutions of tin.

Solution a: 0.1 g of tin are dissolved in 20 cmof sulphuric acid when heated. The solution was transferred to volumetric flask with a capacity of 1 liter, washing the walls of the bulb and 3.5 M sulfuric acid solution, cooled, made up to the mark with this same solution and mix.

1 cmstandard solution contains 0.0001 g of tin.

Solution B: 10 cmstandard solution And transferred to a volumetric flask with a capacity of 100 cmand topped to the mark of 3.5 M sulfuric acid solution and stirred.

1 cmstandard solution B contains 0,00001 g tin.

Solution B is prepared on the day of use.

(Changed edition, Rev. No. 1).

8.3. Analysis

8.3.1. A sample of steel weighing 0.5 g were placed in a glass with a capacity of 250−300 cmor flask with a capacity of 250 cm, flow 15 cmof hydrochloric acid and 5 cmof nitric acid, 2 cmof sulphuric acid and dissolve the sample when heated. After dissolution, the sample solution was evaporated to approximately 10 cm, flow 50 cmof the solution Trilon B, 5 cmof a solution of beryllium nitrate and heated for 5 min. Then pour the ammonia solution before precipitation of hydroxides of metals and an excess of 1−2 cmof solution of ammonia. The solutions and the precipitate was boiled for 1−2 min, remove beaker from heat and sediment to settle for 1 h.

The precipitate was filtered off on a medium density filter (white ribbon) and washed 5−7 times with a weak solution of ammonia, the filtrate discarded. The precipitate from the filter washed with hot water into a glass, which was carried out the precipitation of the hydroxides of the metals.

The filter is washed with 20 cmsulphuric acid 1:4 and twice with hot water. In a glass add 3 cmof nitric acid and evaporate the solution to wet salts.

Salt is dissolved by heating in 10 cmof water, add 4 cmof hydrochloric acid and 10.4 g of ammonium chloride. The solution was transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

From the solution and remove the dissolved oxygen by blowing nitrogen or argon for 5 min and remove polarogram from minus 0.2 to minus 0.8 V, recording the peak recovery of tin at a minus of 0.48 V. the Sensitivity of the device is chosen so that the peak height of the tin reduction was at least 10 mm.

The content of tin in the test solution is determined according to the calibration schedule.

(Changed edition, Rev. No. 1).

8.3.2. Construction of calibration curve.

In beakers or flasks with a capacity of 250 cmis placed 0,5; 1; 2; 4; 5 cmstandard solution B, corresponding to 0,000005; 0,00001; 0,00002; 0,00004; 0,00005 g tin, is poured at 15 cmof hydrochloric acid and 5 cmof nitric acid, 5 cmof sulphuric acid and then the solutions is carried out through all stages of analysis as described in section 8.3.1. At the same time spend control experience.

The value of the peak height reference experiment is subtracted from the value of the peak height of the investigated solution.

(Changed edition, Rev. No. 1).

8.4. Processing of the results

8.4.1. Mass fraction of tin () in percent is calculated by the formula

where  — weight of tin, was found in the calibration schedule g;

the weight of steel,

8.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 12.

Table 12

9. INVERSION-VOLTAMMETRIC METHOD FOR THE DETERMINATION OF TIN (0,0001−0,01%) IN THE STEELS CONTAINING TITANIUM AND NIOBIUM

9.1. The essence of the method

The method is based on the preconcetration of tin on a stationary mercury drop electrode at a potential of minus 0.75 V relative to silver chloride electrode or a minus 0.9 volts relative to the mercury anode in a solution of 0.5 M oxalic acid and 1.10M methylene blue, with the subsequent registration of the current of anodic dissolution of tin at a potential of minus 0.54 relative to silver chloride electrode or a minus 0,73 In respect to the mercury electrode after separation from the main component by coprecipitation with hydroxide of beryllium in the presence of Trilon B.

(Changed edition, Rev. No. 1).

9.2. Apparatus, reagents and solutions

Polarograph AC or polarograph oscilloscope.

The polarographic cell with anode (bottom mercury) or with an external anode (mercury in a saturated solution of potassium chloride), silver chloride reference electrode and a stationary mercury drop electrode, of the type attached to polarography.

Mercury brand RO according to GOST 4658−73 that does not contain moisture.

The gaseous nitrogen according to GOST 9293−74 or argon according to GOST 10157−73.

Oxalic acid according to GOST 22180−76, solutions 90 g/land 45 g/DM.

Methylene blue, aqueous solution of 15 g/DM.

Tin stamps O1 according to GOST 860−75.

Standard solutions of tin.

Solutions A and B (section 8.2).

Solution: 5 cmstandard solution B is transferred to a volumetric flask with a capacity of 50 cmand then filled to the mark with water and mix.

1 cmstandard solution contains 0,000001 g tin.

Solution prepared immediately before use.

(Changed edition, Rev. No. 1).

9.3. Analysis

9.3.1. The separation of tin from major component, dissolution of the precipitate of the hydroxide of beryllium and tin and evaporation of the solution with sulfuric acid to produce wet salts, as described in section 8.3.1.

Salt is dissolved by heating in 10 cmof water and add 25 cm9% solution of oxalic acid. The solution was transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix.

To determine the mass fraction of tin in the polarographic flow cell 20 cma 4.5% solution of oxalic acid, previously purged with nitrogen or argon for 5 min, 0.5 cmof methylene blue, aliquot part of the study solution (table. 13) depending on the assumed mass fraction of tin in steel.

Table 13

Set on polarography potential minus or minus 0.75 V 0.9 V relative to silver chloride electrode or bottom, respectively, of mercury and lead concentration of tin on a stationary mercury drop electrode in a continuously stirred solution for 1 min. At the end of the accumulation time, stop stirring and allow solution to settle down 15, and then remove the anodic polarization curve with linearly varying electrode potential of minus 0.2 V, registering a peak of dissolution of tin in minus or minus 0.54 to 0.73 In relative to silver chloride electrode or the bottom of the mercury. The sensitivity of the device is chosen so that the height of the recorded peak was at least 10 mm. For each dimension, get a new drop of mercury.

(Changed edition, Rev. No. 1).

9.3.2. The tin content find by the method of standard additions. Aliquot part of the standard solution added to the test solution, stirred for 1 min and further analysis have in determining the content of tin in the test solution.

The value of the standard additives is chosen so that the peak height of the tin after the introduction of the additive increased 1.5−2 times.

9.4. Processing of the results

9.4.1. Mass fraction of tin () in percent is calculated by the formula

where is the height of the peak of tin in polarography of test solution, mm;

 — the height of the peak of tin in polarography solution in the reference experiment, mm.

 — the height of the peak of tin after the introduction into a cell of standard addition, mm;

 — the volume of standard addition, cm;

 — concentration of standard solution, g/cm;

 — the weight of the portion corresponding aliquotes become part of the solution

G.

9.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 14.

Table 14

9.4.1, 9.4.2. (Changed edition, Rev. No. 1).

10. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF TIN (0,001−0,01%) IN THE STEELS CONTAINING TITANIUM AND NIOBIUM

10.1. The essence of the method

The method is based on formation of blue coloured complex compounds of tin (IV) with pyrocatechin purple stabilized with gelatin. Light absorption of the solution measured at = 640 nm. Tin is pre-separated from the main components of the steel by precipitation in the form of hydroxide with ammonia in the presence of Trilon B as a complexing substance and using as the collector of the hydroxide of beryllium.

10.2. Apparatus, reagents and solutions

Spectrophotometer, photoelectrocolorimeter, or spectropolarimeter.

a pH meter.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77.

Nitric acid GOST 4461−77 or GOST 11125−78.

Sulfuric acid GOST 4204−77 or GOST 14262−78 and 3.5 M, and diluted 1:4.

Ammonia, aqueous solution according to GOST 3760−79 and diluted 1:100.

Beryllium nitrate, an aqueous solution of 8 g per 100 cm.

Salt is the disodium Ethylenediamine--tetraoxane acid, 2-water (Trilon B), according to GOST 10652−73, a solution of 100 g/DM.

Ascorbic acid food according to GOST 4815−76 a solution of 10 g/DM.

Pyrocatechin purple, 0.001 M solution: 0,4324 g pyrocatechin purple, recrystallized in ethanol, dissolved in water, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water, mix.

Gelatin food according to GOST 11293−78 or GOST 10.53−71, a solution of 5 g/DM.

Tin GOST 860−75 stamps O1.

Standard solutions of tin.

Solution a: 0.1 g of tin are dissolved in 20 cmof sulphuric acid when heated. The solution was transferred to a volumetric flask with a capacity of 1 DM, washing the walls of the bulb and 3.5 M sulfuric acid solution, cooled, made up to the mark with this same solution and mix. 1 cmstandard solution contains 0.0001 g of tin.

Solution B: 10 cmstandard solution And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark of 3.5 M sulfuric acid solution and stirred.

1 cmstandard solution B contains 0,00001 g tin.

Solution B is prepared on the day of use.

(Changed edition, Rev. No. 1).

10.3. Analysis

10.3.1. A sample of steel weighing 0.5 g were placed in a glass with a capacity of 250−300 cmor flask with a capacity of 250 cm, flow 15 cmof hydrochloric acid and 5 cmof nitric acid, 7 cmof sulfuric acid, cover the beaker or the flask with a watch glass and dissolve the sample when heated. After dissolution, the sample solution is evaporated to release vapors of sulfuric acid. Salt is dissolved in 40 cmof water under heating, filtered off the precipitate of silicic acid on two medium density filter (white ribbon), the filter and the precipitate was washed 3−4 times with hot water, the filter is discarded. The filtrate with washings was evaporated to a volume of 50 cm.

To the solution was added to 7−10 cmof ammonia solution with stirring, poured 50 cmof the solution Trilon B solution and boil for 10−15 min. Add 5 cmof a solution of beryllium nitrate, ammonia solution before precipitation of hydroxides of metals and an excess of 1−2 cm. Solution and the precipitate was heated at 70−80°C for 10 minutes, bringing it to a boil. The beaker with contents is cooled in running water for 45−60 min. the Precipitate was filtered off on a medium density filter (white ribbon) and washed 5−7 times with diluted ammonia solution (1:100). The filtrate is discarded. The precipitate from the filter washed with hot water in a glass or a flask, which produced the precipitation of hydroxides of metals.

The filter is washed with 20 cmof sulphuric acid (1:4) and 2 times with hot water. The solution was evaporated to approximately 10 cm, flow 50 cmof the Trilon B solution and heated for 5 min. Then pour the ammonia solution before precipitation of hydroxides of metals and an excess of 1−2 cm. Solution and the precipitate was boiled for 1−2 min. the Precipitate was filtered off on a medium density filter (white ribbon) and washed 5−7 times in hot water. The filtrate is discarded. The precipitate from the filter washed with hot water in a glass or flask, which carried out the precipitation of hydroxides of metals. The filter is washed with 20 cmsulphuric acid 1:4, 2 times with hot water and discarded. To the filtrate add 5−7 cmof nitric acid and the solution was evaporated to wet salts. The walls of the beaker or flask is washed with water and again evaporated to moist salts. Salt is dissolved in 10 cmwater when it is heated, cooled. The solution was transferred to a beaker with a capacity of 100 cm, pour 1 cmof ascorbic acid solution, mix and set pH to 2.2 with a solution of ammonia using pH meter. The solution is poured 1 cmof solution of gelatin, 1.5 cmpyrocatechin purple solution and stirred solution. After 20 min the solution was transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water, mix and measure the optical density of the solution on the spectrophotometer at a = 640 nm or photoelectrocolorimeter with a filter having a region of transmittance in the range of wavelengths from 610 to 700 nm. As a solution comparison, use water. Simultaneously conduct control experience for contamination of reagents.

The tin content found by the calibration schedule subject to amendments the reference experiment.

(Changed edition, Rev. No. 1).

10.3.2. Build graduirovochnyh graphics.

Seven of cups with a capacity of 250−300 cmor flasks with a capacity of 250 cmis placed 0.5 g of carbonyl iron. Six of cups or flasks poured consistently 0,5; 1; 2; 3; 4; 5 cmstandard solution B, which corresponds to 0,000005; 0,00001; 0,00002; 0,00003; 0,00004; 0,00005 g tin. The seventh beaker or flask serves for the control experience. All beakers or flasks poured 15 cmof hydrochloric acid and 5 cmof nitric acid, 5 cmof sulfuric acid, cover the cups or flasks watch glass and dissolve the sample when heated. Further analysis is carried out as specified in clause 10.3.1.

From the values of optical density of analyzed solutions is subtracted the value of optical density in the reference experiment. The found values of optical density and corresponding values of tin concentrations to build calibration curve.

(Changed edition, Rev. No. 1).

10.4. Processing of the results

10.4.1. Mass fraction of tin () in percent is calculated by the formula

where  — weight of tin, was found in the calibration schedule g;

the weight of steel,

10.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 15.

Table 15

11. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF ZINC (0,0005−0,01%) AND CADMIUM (0,0005−0,01%)

11.1. The essence of the method

The method is based on measuring absorption of radiation by free atoms of zinc or cadmium, generated by spraying hydrochloric acid solution of zinc and cadmium in a flame air-acetylene.

Tungsten, niobium, silicon and titanium are separated by acid hydrolysis.

11.2. Equipment, reagents, solutions

Atomic absorption spectrophotometer, equipped with a burner for operation in a flame air-acetylene.

Lamp to determine zinc.

Lamp for determination of cadmium.

The cylinder with acetylene.

The compressor supplying compressed air, or compressed air.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77 and diluted 1:1.

Nitric acid GOST 4461−77 or GOST 11125−78 and diluted 1:1,1:2.

Radio engineering carbonyl iron according to GOST 13610−79 or normative-technical documentation.

Zinc brand TSO according to GOST 3640−79.

Standard solutions of zinc.

Solution a: 0.1 g of zinc metal is placed in a beaker or flask with a capacity of 250−300 cmand dissolved by heating in 100 cmof hydrochloric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of zinc.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of zinc.

Solution B is prepared on the day of use.

Cadmium brand KDO according to GOST 1467−77.

Standard solutions of cadmium.

Solution a: 0.1 g of cadmium is placed in a glass or in a flask with a capacity of 250−300 cmand dissolved by heating in 30 cmof nitric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of cadmium.

Solution B: 10 cmsolution And placed in a flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of cadmium.

Solution B is prepared on the day of use.

Manganese GOST 6008−82, a solution of 5 g/DM: 0.5 g of manganese placed in a beaker or flask with a capacity of 250−300 cm, dissolved by heating in 30 cmof nitric acid (1:1) and cooled. The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.005 g of manganese.

Cobalt GOST 123−78, a solution of 10 g/DM: 1 g of metallic cobalt were placed in a glass or flask with a capacity of 250−300 cm, dissolved by heating in 80 cmof hydrochloric acid (1:1) and cooled. The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of cobalt.

Molybdenum, a solution of 5 g/DM: 0.5 g of molybdenum were placed in a glass or flask with a capacity of 250−300 cm, dissolved by heating in a mixture of 20 cmof hydrochloric acid and 5 cmof nitric acid.

The solution was evaporated to wet salts. Salt dissolved in 5 cmof hydrochloric acid when heated. The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.005 g of molybdenum.

Chrome according to GOST 5905−79, a solution of 10 g/DM: 1 g of chromium was placed in a beaker or flask with a capacity of 250−300 cm, dissolved by heating in 30 cmof hydrochloric acid and cooled. The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of chromium.

Nickel GOST 9722−79, a solution of 10 g/DM: 1 g of metallic Nickel is placed in a beaker or flask with a capacity of 250−300 cm, dissolved by heating in 30 cmof nitric acid and cooled. The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of Nickel.

Primary aluminium GOST 11069−74, a solution of 10 g/DM: 1 g of aluminium is dissolved in 30 cmof hydrochloric acid diluted 1:1.

The solution was transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1

cmof the solution contains 0.01 g of aluminum.

11.3. Preparation of the spectrophotometer

Preparation of the spectrophotometer is carried out in accordance with the instructions for the device. Set the spectrophotometer at a resonance line 213,9 nm for the determination of zinc and 228 nm for the determination of cadmium. After switching on the gas flow and ignition of the burner spray water and set the zero of the instrument.

11.4. Analysis

11.4.1. A sample of steel of 1 g for the mass concentration of zinc or cadmium from 0.0005 to 0.001%; 0.5 g for the mass concentration of zinc or cadmium, St. 0,001 to 0.005%; 0.25 g when the mass fraction of zinc or cadmium, St of 0.005 to 0.01% is placed in a beaker with a capacity of 200−300 cmor flask with a capacity of 250 cm, 30 cm, pouredsalt and 10 cmof nitric acid, cover the beaker or the flask with a watch glass and heated to dissolve sample. The solution was evaporated to wet salts, the residue is dissolved in 5 cmof hydrochloric acid. Pour 20−30cmof water, transfer the solution into a measuring flask with a capacity of 50 cm, made up to the mark with water and mix.

The resulting solution was filtered through a dry two medium density filter (white ribbon) in a dry conical flask with a capacity of 50 cm. The first portion of the filtrate discarded. Spray the solution and measure the value of the degree of absorption of the radiation of the lamp with the zinc atoms at a wavelength of = 213,9 nm or cadmium at a wavelength = 228 nm.

Before spraying the test solution sprayed water to wash the system and check the zero point.

The content of zinc or cadmium found by the calibration schedule, as amended by the control of op

it.

11.4.2. Construction of calibration curve.

In five glasses or flasks with a capacity of 250−300 cmis placed sample of carbonyl iron, solutions of Nickel, chromium, manganese, cobalt, molybdenum and aluminium in quantities corresponding to their content in the analyzed steel.

In four glasses poured successively 0,5; 1; 3; 5 cmstandard solution B of zinc, which corresponds to 0,000005; 0,00001; 0,00003; 0,00005 g zinc and 0.5; 1; 3; 5 cmstandard solution of cadmium nitrate, which corresponds to 0,000005; 0,00001; 0,00003; 0,00005 g of cadmium.

The fifth beaker or flask serves for the control experience. Poured 30 cmsalt and 10 cmof nitric acid, cover glasses, watch glasses, and dissolve the sample when heated.

Further analysis is carried out as specified in clause 11.4.1.

From the values of optical density of analyzed solutions is subtracted the value of the optical density of the solution in the reference experiment.

The found values of optical density and corresponding values of the concentrations of zinc and cadmium to build calibration graphs.

11.5. Processing of the results

11.5.1. Mass fraction of zinc or of cadmium (a) in percent is calculated by the formula

where is the mass of zinc or cadmium was found in the calibration schedule g;

the weight of steel,

(Changed edition, Rev. No. 1).

11.5.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 16.

Table 16

12. POLAROGRAPHIC METHOD FOR THE DETERMINATION OF ZINC (0,0015−0,01%) AND CADMIUM (0,001−0,01%) IN STEELS CONTAINING TUNGSTEN, MOLYBDENUM, TITANIUM AND NIOBIUM

12.1. The essence of the method

The method is based on the ability of the zinc and cadmium to recover on dripping mercuric electrode at a potential peak for zinc minus 1.17, for cadmium — minus 0.70 per regarding mercury anode in the background of 1 M phosphoric acid.

Zinc and cadmium are pre-separated from the main components of the steel by precipitation as sulphides by the thioacetamide in ammoniacal solution (pH 7.5) in the presence of tartaric acid as complexing agents.

(Changed edition, Rev. No. 1).

12.2. Apparatus, reagents and solutions

Polarograph AC.

The polarographic cell, made of glass with anode (bottom mercury) and mercury-drip cathode attached to polarography.

Thermometer pH meter.

The mercury brand of RO or R1 according to GOST 4658−73 that does not contain moisture.

The gaseous nitrogen according to GOST 9293−74 or argon according to GOST 10157−79.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77 diluted 1:1.

Nitric acid GOST 4461−77 or GOST 11125−78 diluted 1:1.

Tartaric acid according to GOST 5817−77, a solution of 500 g/DM.

Sulfuric acid GOST 4204−77 or GOST 14262−78.

Ammonia, aqueous solution according to GOST 3760−79.

The thioacetamide aqueous solution of 20 g/DM.

A mixture of hydrochloric and nitric acids is freshly prepared (to 150 cmof hydrochloric acid pour 50 cmof nitric acid and stirred) and diluted 1:1.

Orthophosphoric acid according to GOST 6552−80, and diluted 1:3.

Radio engineering carbonyl iron according to GOST 13610−79.

Copper grade MO according to GOST 859−78, a solution of 1 g/DM: 1 g of copper is dissolved by heating in 7−10 cmof nitric acid (1:1).

The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.01 g of copper.

Zinc brand TSO according to GOST 3640−79.

Standard solutions of zinc.

Solution a: 0.1 g of zinc were placed in a glass with a capacity of 250−300 cmand dissolved by heating in 100 cmof hydrochloric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of zinc.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of zinc.

Cadmium brand KDO according to GOST 1467−77.

Standard solutions of cadmium.

Solution a: 0.1 g of cadmium is placed in a beaker with a capacity of 250−300 cmand dissolved by heating in 30 cmof nitric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of cadmium.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmstandard Rasbora B has the 0.00001 g of cadmium.

Universal indicator paper.

(Changed edition, Rev. No. 4).

12.3. Analysis

12.3.1. Weighed 0.5 g of steel placed in a beaker with a capacity of 250−300 cmor flask with a capacity of 250 cm, 30 cm, pouredsalt and 10 cmof nitric acid, cover the beaker or the flask with a watch glass and heated to dissolve sample. The solution was evaporated to a volume of approximately 10 cm, 30 cm, pour thewater, 25 cmof tartaric acid and warmed for 5−10 min.

Then add 30 cmof ammonia solution to pH 8−9 and again heated for 5−10 min to dissolve the precipitated tungsten acid. Pour 1 cmof a solution of copper nitrate and establish a pH of 7.5 with hydrochloric acid (1:1) using pH meter. The solution is diluted with water to 150 cm, heated to boiling and removed the Cup with the solution from the plate. Add two servings of 10 cmsolution of thioacetamide with an interval time of 5 min.

After 4 h, the precipitate filtered off sulphides in two medium density filter (white ribbon), washed 7−8 times with cold water. The filtrate is discarded. The precipitate is dissolved on the filter with 30−40 cmhot mix of hydrochloric and nitric acids (1:1) in portions of 10 cm, collecting the solution in a beaker or flask, which produces the precipitation of the sulphides. The filter was washed 3−4 times with hot water, adding the wash liquid to the main filtrate.

The solution was added 2 cmof sulphuric acid and evaporated to moist salts. To the residue in a glass, pour 5 cmof water, 14 cmdiluted phosphoric acid, transfer the solution into a measuring flask with a capacity of 50 cm, made up to the mark with water and mix. Purged the solution with nitrogen or argon for 10 min and remove polarogram from minus 0.5 to minus 1.4, registering peaks of the recovery of cadmium and zinc, respectively, at minus 0.70 per and minus of 1.17 V.

The contents of zinc and cadmium found by the calibration schedule subject to amendments the reference experiment.

(Changed edition, Rev. No. 1).

12.3.2. Construction of calibration graphs.

Six glasses or flasks with a capacity of 250−300 cmis placed 0.5 g of carbonyl iron. Five beakers or flasks poured consistently 0,5; 1; 2; 3; 4; 5 cmstandard solution B of zinc, which corresponds to 0,000005; 0,00001; 0,00002; 0,00003; 0,00004; 0,00005 g zinc and 0,5; 1; 2; 3; 4; 5 cmstandard solution of cadmium, which corresponds to 0,000005; 0,00002; 0,00003; 0,00004; 0,00005 g of cadmium. The sixth beaker or flask serves for the control experience.

All beakers or flasks go for 30 cmof hydrochloric and 10 cmof nitric acid, cover glasses, watch glasses and heated to dissolve batches.

Further analysis is carried out as specified in clause 12.3.1.

From the value of the peak height analyzed solutions subtract the value of the peak height reference experiment.

The found values of the peak height and the corresponding values of the concentrations of zinc and cadmium to build calibration graphs.

(Changed edition, Rev. No. 1).

12.4. Processing of the results

12.4.1. Mass fraction of zinc or of cadmium (a) in percent is calculated by the formula

where is the mass of zinc or cadmium was found in the appropriate calibration schedule g;

the weight of steel,

12.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 17.

Table 17

13. POLAROGRAPHIC METHOD FOR DETERMINING LEAD (0,001−0,01%), ZINC (0,0015−0,01%) AND CADMIUM (0,001−0,01%) IN THE STEELS CONTAINING TUNGSTEN, MOLYBDENUM, TITANIUM, NIOBIUM

13.1. The essence of the method

The method is based on the ability of lead, zinc and cadmium to recover on dripping mercuric electrode at a potential peak for lead — minus 0.5 V for zinc — minus 1.17, for cadmium — minus 0.7 V relative to the mercury anode in the background of 1 M phosphoric acid.

Lead, zinc and cadmium pre-separated from the main components of the steel strong-base anion exchange resin with 2 M hydrochloric acid solution.

13.2. Apparatus, reagents and solutions

Polarograph AC.

The polarographic cell, made of glass with anode (bottom mercury) and mercury-drip cathode attached to polarography.

Mercury brand RO according to GOST 4658−73 that does not contain moisture.

The gaseous nitrogen according to GOST 9293−74 or argon according to GOST 10157−73.

The chromatographic column with a diameter of 1.5−2.0 cm, is filled with the anion exchange resin layer height of 12−15 cm.

Anion-exchange resin according to GOST 20301−74 brand AB-17−8-CHS.

13.2.1. Preparation of anion exchange resin for analysis.

100−150 cmcommodity anion exchange resin (available in the form of a slurry in water) was washed twice with water by decantation method. To separate the resin fraction with a grain size of less than 0.6 mm, the slurry of resin in water poured into a sieve No. 063 GOST 6613−73 and washed with water, collecting the past through a sieve fraction of the anion exchanger with water in a vessel with a capacity of 2−3 DM. Remaining on the sieve resin cast. The fraction of the anion exchanger, passed through a sieve, washed twice with hydrochloric acid (1:30) by the method of decanting, and then hydrochloric acid (1:1) to the lack of iron ions (sample with ammonium radamisty) and water 4−5 times.

The resin was treated with a solution of 50 g/DMsodium hydroxide to a negative reaction on chloride ions (test with silver nitrate) and then with water to neutral reaction on the universal indicator and transferred to the column bottom of which a pre-place pad of glass wool. The layer of anion exchange resin in the column should be smooth without air bubbles. After filling the column through it at a speed of 1 cm/min is passed in the beginning of 120−150 cmof hydrochloric acid (1:30), then 120−150 cmof hydrochloric acid (1:2) and 100 cmof water.

Glass wool to fill the chromatographic column.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77, 2 M, 0.5 M, 0.02 m, and diluted 1:1, 1:30, 1:100.

Nitric acid GOST 4461−77 or GOST 11125−78, 2 M and diluted 1:1.

Sulfuric acid GOST 4204−77 or GOST 14262−78.

Perchloric acid, a solution of 570 g/DM.

Orthophosphoric acid according to GOST 6552−80, and diluted 1:3.

Ammonium radamisty, a solution of 50 g/DM.

Radio engineering carbonyl iron according to GOST 13610−79 or normative-technical documentation.

Sodium hydroxide according to GOST 4328−77, a solution of 50 g/DM.

Lead brand WITH GOST 3778−77.

Standard solutions of lead.

Solution a: 0.1 g of lead is dissolved by heating in 30 cmof nitric acid. The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmof the solution contains 0.0001 g of lead.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, add 2 cmof hydrochloric acid, made up to the mark with water and mix.

1 cmof solution B has the 0.00001 g of lead.

Solution B is prepared on the day of use.

Zinc brand TSO according to GOST 3640−79.

Standard solutions of zinc.

Solution a: 0.1 g of zinc were placed in a glass with a capacity of 250−300 cmand dissolved by heating in 100 ml of hydrochloric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of zinc.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of zinc.

Solution B is prepared on the day of use.

Cadmium brand KDO according to GOST 1467−77.

Standard solutions of cadmium.

Solution a: 0.1 g of cadmium is placed in a beaker with a capacity of 250−300 cmand dissolved by heating in 30 cmof nitric acid (1:1). The solution was cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

1 cmstandard solution contains 0.0001 g of cadmium.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmstandard solution B has the 0.00001 g of cadmium.

Solution B is prepared on the day of use.

Indicator

R-universal paper.

13.3. Analysis

13.3.1. The weight of the portion became 1 g when the mass fraction of lead from 0.001 to 0.005%; zinc from 0.0015 to 0.005% and cadmium from 0.001 to 0.005%; 0.5 g when the mass fraction of lead of St. 0.005−0.01%; zinc St 0.005−0.01%; cadmium SV 0.005−0.01% is placed in a beaker with a capacity of 200−300 cmor flask with a capacity of 250 cm, 30 cm, pouredsalt and 10 cmof nitric acid, cover the beaker or the flask with a watch glass and heated to dissolve sample.

The solution was evaporated to wet salts. To the residue poured 5cmof hydrochloric acid and heated to dissolve the salts. The solution is poured 50 ml of hot water, heated to 80−90°C, filtered off the precipitate of silicic acid on two medium density filter (white ribbon) and washed 6−7 times with hot hydrochloric acid (1:100). The filter with the sediment is discarded and the filtrate is evaporated to wet salts. Pour 5 cmof hydrochloric acid, cover beaker or flask with a watch glass, heated to dissolve the salts, and cooled. The solution was poured 25 cmof water.

A chromatographic column is washed with 50 cmof 2 M hydrochloric acid solution. The solution passed through the column at a rate 1−1,5 cm/min. When the solution level in the column will be 1−2 cm above the layer of resin, then rinsed a glass of 5−6 cmof 2 M hydrochloric acid solution and transfer the washing liquid in the column. Repeat this operation 3 more times and wash the upper part of the column 2−3 times 5−6 cmof 2 M hydrochloric acid solution.

Passed through a column of 100 cmof 2 M hydrochloric acid solution. Then ion-exchange column washed with 50−60 cmof 0.5 M hydrochloric acid solution to remove iron from the column.

The filtrate, Ambra

charge.

13.3.2. Lead and zinc desorber 150 ml of 0.02 M hydrochloric acid solution at a speed of 1−1,5 cm/min, collecting the eluate in a glass or flask with a capacity of 300−400 cm.

Cadmium desorbent 80 cmof 2 M nitric acid solution at a speed of 1−1,5 cm/min, collecting the eluate in the same Cup. The column was washed with water to neutral reaction on the universal indicator.

The filtrate is discarded.

To eluate containing lead, zinc and cadmium poured 3 cmof perchloric acid and evaporate the solution to start the selection of the vapor of perchloric acid. Then wash the side of the Cup with water, add 14 cmof phosphoric acid (1:3), the solution transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix. Purged the solution with nitrogen or argon for 10 min and remove polarogram from minus 0.2 to minus 1.4, registering peaks of the recovery of lead, zinc and cadmium respectively at minus 0,51, minus 0.7 and minus of 1.17 V.

The content of lead, zinc and cadmium found by the calibration schedule subject to amendments the reference experiment

.

13.3.3. (Deleted, Rev. No. 1).

13.3.4. Construction of calibration graphs.

Seven of cups with a capacity of 250−300 cmor flasks with a capacity of 250 cmis placed 0.5 g of carbonyl iron. Six glasses poured consistently 0,5; 1; 2; 3; 4; 5 cmstandard lead solution B, which corresponds to 0,000005; 0,00001; 0,00002; 0,00003; 0,00004; 0,00005 g lead; 0,5; 1; 2; 3; 4; 5 cmstandard solution B of zinc, which corresponds to 0,000005; 0,00001; 0,00002; 0,00003; 0,00004; 0,00005 g zinc and 0,5; 1; 2; 3; 4; 5 cmstandard solution of cadmium, which corresponds to 0,000005; 0,00001; 0,00002; 0,00003; 0,00004; 0,00005 g of cadmium. The seventh glass is used for the reference experiment.

All beakers or flasks go for 30 cmof hydrochloric and 10 cmof nitric acid, cover glasses, watch glasses and heated to dissolve batches.

Then do as described in section 13.3.1.

From the height of the polarographic wave (peak) of the analyzed solutions of subtracted value for the height of the polarographic wave (peak) control experience.

The found values of the height of the polarographic wave (peak) and the corresponding values of the concentrations of lead, zinc and cadmium to build calibration graphs

.

13.4. Processing of the results

13.4.1. Mass fraction of lead, of zinc or of cadmium (a) in percent is calculated by the formula

where is the mass of lead, zinc or cadmium was found in the appropriate calibration schedule g;

the weight of steel,

13.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level = 0.95 does not exceed the values specified in table. 18.

Table 18