GOST 1652.3-77

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  ГОСТ 1652.3-77

GOST 1652.3−77 Alloys copper-zinc. Methods for determination of iron (with Amendments No. 1, 2, 3, 4)

GOST 1652.3−77

Group B59

STATE STANDARD OF THE USSR

ALLOYS COPPER-ZINC

Methods of iron determination

Copper-zinc alloys. Methods for the determination of iron

AXTU 1709

Date of introduction 1978−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

DEVELOPERS

Y. F. Chuvakin, M. B. Taubkin, A. A. Nemodruk, N. In. Egiazarov (supervisor), I. A. Vorobyev

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 27.04.77 N 1062

3. REPLACE GOST 1652.3−71

4. The standard fully complies with ISO 4748−84*, ISO 1812−76
________________
* Access to international and foreign documents referred to here and hereinafter, can be obtained by clicking on the link to the site shop.cntd.ru. — Note the manufacturer’s database.

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Resolution of the state standard from 28.12.92 N 1525 removed the limitation of the validity period

7. REVISED (June 1997) with Amendments No. 1, 2, 3, 4, approved in October 1981 and November 1987, October 1990, December 1992 (IUS 12−81, 2−88, 2−90, 3−93)


This standard establishes titrimetric chelatometric method for determination of iron (at mass fraction of iron from 1 to 5%), photometric methods of determination of iron (at mass fraction of iron from 0.01 to 2%) and atomic absorption method (with a mass fraction of from 0.01 to 5%) in copper-zinc alloys according to GOST 15527, GOST and GOST 17711 1020.

The standard fully complies with ISO 4748−84, ISO 1812−76.

(Changed edition, Rev. N 3).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 25086 with the Supplement according to claim 1.1 GOST 1652.1.

(Changed edition, Rev. N 2).

2. TITRIMETRIC CHELATOMETRIC METHOD FOR DETERMINATION OF IRON

2.1. The essence of the method

The method is based on titration of ferric iron by solution of Trilon B with the use of sulfosalicylic acid as indicator.

2.2. Reagents and solutions

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

Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:4.

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

Sulfosalicylic acid according to GOST 4478, solution 100 g/DM.

Disodium salt of Ethylenediamine-, , , -tetraoxane acid 2-water (Trilon B) according to GOST 10652, 0,025 mol/DMsolution; prepared as follows: 9,305 g Trilon B dissolved in 500 cmof water when heated, transferred to a volumetric flask with a capacity of 1 DMand topped to the mark with water.

Iron, standard sample No. 126 (low carbon steel). Standard solution of iron is prepared as follows: 1,005 g of the standard sample N 126 was dissolved with heating in 20 cmof nitric acid, diluted 1:1. The solution was boiled to remove oxides of nitrogen, 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 0.001 g of iron.

The installation of the mass concentration of the solution Trilon B

10 cmof a standard solution of iron was placed in a conical flask with a capacity of 250 cm, add 20 cmof water and neutralized with ammonia solution diluted 1:1 before passing blue color of the indicator paper, Congo lilac, then add 5 cmof hydrochloric acid diluted 1:4, top up with water to 100 cmand further analysis are as indicated in claim 2.3.

(Changed edition, Rev. N 4).

2.3. Analysis

A sample of alloy weighing 0.5 g when the mass fraction of iron to 3% and 0.25 g when the mass fraction of iron in excess of 3% is dissolved by heating in 20 cmof nitric acid, diluted 1:1 in glass with a capacity of 300 cm, is diluted with water to about 200 cm, and add the ammonia solution before the formation of soluble blue ammonium complex copper. The solution was maintained at (60±5)°C for coagulation of the precipitate of iron hydroxide.

The precipitate was filtered off on a medium density filter and washed with ammonia solution, diluted 1:50. The precipitate is washed with hot water into a glass, which conducted the deposition, and dissolved in 10 cmof hot hydrochloric acid, diluted 1:1.

The filter is washed with hot water. Repeat the precipitation of iron hydroxide in ammonia solution, filtering and washing the precipitate. The precipitate of iron hydroxide filter wash with hot water in a conical flask with a capacity of 250 cm, is dissolved in 10 cmof hot hydrochloric acid, diluted 1:1, and washed the filter with hot water.

The flask with the solution was heated until complete dissolution of the precipitate is neutralized with ammonia solution diluted 1:1 before passing on blue indicator paper, Congo lilac, add 5 cmof hydrochloric acid diluted 1:4, top up with water to 100 cmand heated to 70 °C. Pour 5 cmsulfosalicylic acid solution and titrate the hot solution with a solution of Trilon B before transition of colouring from brown-red to lemon yellow.

2.4. Processing of the results

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

,

where  — volume of solution Trilon B, used for titration, cm;

 — weight of iron, corresponding to 1 cmof 0.025 mol/DMsolution of Trilon B, g;

 — the weight of the portion of alloy,

(Changed edition, Rev. N 4).

2.4.2. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed 0,07% when the mass fraction of iron from 1% to 3% and 0.1% when the mass fraction of iron from 3 to 5%.

2.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (the reproducibility) shall not exceed 0.1% when the mass fraction of iron from 1% to 3% and 0.14% when the mass fraction of iron from 3 to 5%.

2.4.2, 2.4.3. (Changed edition, Rev. N 2, 4).

2.4.4. The control accuracy of the analysis carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) copper-zinc alloys, approved GOST 8.315, or by additives, or by comparing the results obtained by another method in accordance with GOST 25086.

(Changed edition, Rev. N 4).

2.4.4.1, 2.4.4.2. (Deleted, Rev. N 4).

3. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON

3.1. The essence of the method

The method is based on formation of a colored iron complex with 1,10-fenantrolina or , -dipyridil at pH 5 in the presence of sodium acetate and hydroxylamine hydrochloride after separation of iron by precipitation with aluminum hydroxide.

3.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

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

Hydrofluoric acid according to GOST 10484.

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

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

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

Acetic acid according to GOST 61.

Sodium acetate according to GOST 199.

Phenolphthalein solution in ethanol, 1 g/DM.

Ammonium-aluminum sulphate (aluminum-ammonium alum) according to GOST 4238, solution; for its preparation, 10 g of alum is dissolved in 1 DMof water with 10 cmof concentrated sulfuric acid.

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

1,10-fenantrolin, solution; is prepared as follows: 1.5 g 1,10-phenanthroline dissolved by heating in a small amount of water with a few drops of hydrochloric acid and dilute with water to 1000 cm, store the solution in a dark container.

The solution is a buffer; prepared as follows: 272 g sodium acetate and dissolve in 500 cmof water, add 240 cmof acetic acid, filter and add water to 1 DM.

The reaction mixture, freshly prepared; prepared as follows: one part of a solution of hydroxylamine hydrochloric acid is mixed with one part of the 1,10-phenanthroline or , -dipyridyl and with the two parts of buffer solution.

The standard iron solution.

Solution a: prepared as follows: 0,5025 g standard sample N 126 steel (low carbon steel) was dissolved in 20 cmof nitric acid, diluted 1:1. The resulting solution is boiled to remove oxides of nitrogen, 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 0.0005 g of iron.

Solution B is prepared on the day of application: 5 cmsolution And placed in a flask with a capacity of 100 cm, made up to the mark with water and mix. 1 cmof solution B contains 0.00025 g of iron.

Bromatologia acid according to GOST 2062.

Bromine according to GOST 4109.

The acid chloride.

, -dipyridyl solution: 1.5 g , -dipyridyl dissolved by heating in a small amount of water with a few drops of hydrochloric acid, and dilute with water to 1 DM. Store the solution in a dark container.

Mix to dissolve, freshly prepared; prepared as follows; ten volumes bromatological acid is mixed with one

the volume of bromine.

3.3. Analysis

3.3.1. For alloys not containing silicon and tin

A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 250 cm, cover with a watch glass and carefully dissolved by heating in 15 cmof nitric acid, diluted 1:1. The glass solution was cooled, washed walls and glass with a little water and the solution diluted with water to a volume of 150 cm. Add 5 cmof a solution of alum alimohammadian (for alloys not containing aluminum) and ammonia diluted 1:1, until the formation of a soluble blue complex of copper. The solution is kept at 60 °C for coagulation of the precipitate hydroxides of iron and aluminum. The separated precipitate was filtered off on a medium density filter and washed with ammonia solution, diluted 1:50. The residue is dissolved in 10 cmof hot hydrochloric acid, diluted 1:1. The filter carefully washed with hot water, collecting the solution in a glass, where he conducted the deposition, and re-precipitated hydroxide of iron and aluminum with ammonia. The precipitate was filtered off, washed with ammonia solution, diluted 1:50 and dissolved in 10 cmof hot hydrochloric acid, diluted 1:1. The filter is washed with hot water, collecting the washings in the beaker, in which was conducted the deposition.

The solution was transferred to volumetric flask, dilute to the mark with water and, depending on the iron content in the alloy, selected aliquot part in accordance with the table.1.

Table 1

Aliquot part of the solution is placed in a volumetric flask with a capacity of 50 cm, top up with water to 25 cmand neutralized with ammonia, diluted 1:1, phenolphthalein, add 1 cmof hydrochloric acid diluted 1:1, and 12 cmof the reaction mixture, made up to the mark with water and mix. After 30 min measure the optical density on the spectrophotometer in a cuvette with a layer thickness of 1 cm at a wavelength of 510 nm or photoelectrocolorimeter with a green filter. Solution comparison is the solution of the reference experiment.

3.3.2. For alloys containing silicon

A sample of alloy weighing 0.5 g is placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid, diluted 1:1 with the addition of 2−3 cmhydrofluoric acid. The solution was evaporated almost to dryness. The dry residue is treated with 10 cmof concentrated nitric acid and repeat the evaporation. This process is repeated one more time. Then pour 10 cmof nitric acid, diluted 1:1, heated for a few minutes, pour 15−20 cmof hot water and after dissolution, the salt solution was transferred into a glass with a capacity of 250 cm, is diluted with water to a volume of 150 cm, adding 5 cmof a solution of aluminum ammonium alum and further analysis are as indicated in claim 3.3.1.

3.3.3. For alloys containing tin

A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 250 cm, injected 15 cmof the mixture to dissolve, cover with a watch glass and carefully dissolved by heating. In case of incomplete dissolution, add dropwise bromine. Then add 20 cmof perchloric acid for complete removal of the bromides of tin and antimony are heated in the solution to reduce its volume to 5 cm. The solution was cooled, washed the side of the Cup a small amount of water (about 30 cm) and heated to dissolve the salts.

If the lead alloy is present, then its branches are added to the solution 50 cmof water 5 cmof sulphuric acid diluted 1:1, and heated. The solution was cooled, the precipitate is filtered off on a tight filter and washed 4−5 times with water acidified with sulfuric acid. The precipitate is discarded.

The filtrate or the solution after dissolution of salts diluted with water to a volume of 150 cm, add 5 cmof a solution of alum alimohammadian and further analysis are as indicated in claim 3.3.1.

3.3.4. Construction of calibration curve

In a volumetric flask with a capacity of 50 cmpoured from microburette consistently 0; 0,2; 0,5; 1,0; 1,5; 2,5; 3,5 and 5.0 cmof solution B, add water to 25 cm, pour 2−3 drops of solution of phenolphthalein and neutralized with ammonia, diluted 1:1. Further analysis are as indicated in claim 3.3.1.

Solution comparison is the solution not containing iron.

On the found values of optical densities of solutions and their corresponding grades of iron to build the calibration graph.

3.4. Processing of the results

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

,

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

 — the weight of the portion corresponding to aliquote part,

3.4.2. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed the values given in table.2.

Table 2

(Changed edition, Rev. N 4).

3.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (the reproducibility) shall not exceed the values specified in table.2.

(Changed edition, Rev. N 2, 4).

3.4.4. The control accuracy of the analysis carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) copper-zinc alloys, approved GOST 8.315, or by additives, or by comparing the results obtained by another method in accordance with GOST 25086.

(Changed edition, Rev. N 4).

3.4.4.1−3.4.4.3. (Deleted, Rev. N 4).

4. PHOTOMETRIC METHOD SULFOSALICYLIC ACID

4.1. The essence of the method

The method is based on formation of yellow complex compound of iron with sulfosalicylic acid in an ammonia environment after the release of his coprecipitation with aluminum hydroxide or lanthanum and measuring the optical density of the solution at a wavelength of 420 nm.

4.2. Equipment, reagents, solutions

Spectrophotometer or photoelectrocolorimeter.

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

Hydrochloric acid according to GOST 3118 and diluted 1:1 and 1:9.

A mixture of concentrated hydrochloric and nitric acids in the ratio 3:1.

Hydrofluoric acid according to GOST 10484.

Ammonia water according to GOST 3760 and diluted 1:19.

Lanthanum nitrate, a solution of 0.3 g of lanthanum nitrate dissolved in 20 cmof water with a few drops of 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.

Aljumokalievyh alum GOST 4329, solution 20 g/l: 20 g aljumokalievyh alum dissolved in water with the addition of 15 cmof hydrochloric acid. Solution top up with water to 1 DM.

Aluminium metal according to GOST 11069, of 0.1% solution: 1.0 g of aluminium is dissolved in 15−20 cmof concentrated hydrochloric acid and add water to 1 DM.

Hydrogen peroxide according to GOST 10929.

Potassium-sodium vinocity according to GOST 5845, a solution of 200 g/DM.

Sulfosalicylic acid according to GOST 4478, solution 100 g/DM.

The iron metal.

Iron oxide.

Standard iron solution: 0,1430 g of iron oxide or 0,1000 g of iron dissolved in 30 cmof hydrochloric acid diluted 1:1 with the addition of a few drops of hydrogen peroxide. 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 0.1 mg of iron.

4.3. Analysis

4.3.1. For alloys containing up to 0.05% silicon

A sample of alloy weighing 1 g is placed in a beaker with a capacity of 400 cmand dissolved in 15 cmof the mixture of acids when heated. After dilution with water rinse walls of beaker and watch glass, the solution was diluted to 150 cm; when the alloy contains less than 0.5% of aluminium in solution was added 5 cmof a solution of aluminium nitrate or lanthanum.

The solution is heated to 70 °C and add ammonia until the formation of a soluble blue complex of copper and 5 cmin excess. Solution and the precipitate is kept at a temperature of 60−70°C for 20 min. Then the precipitate was filtered off on a medium density filter and washed with ammonia solution, diluted 1:19. The filter cake is dissolved in 10 cmof hydrochloric acid diluted 1:1 with the addition of 2−3 drops of hydrogen peroxide, collecting the solution in a glass, which conducted the deposition, and after dissolving the filter thoroughly washed with hot water. The solution was heated for 2−3 min to remove bubbles of hydrogen peroxide, then dilute with water to 150 cmand the deposition is repeated. After dissolution of the precipitate, thoroughly washing the filter with hot water and removal of hydrogen peroxide solution with an iron content of over 0.05% is transferred to a volumetric flask with a capacity of 100 or 250 cm, is poured a solution of hydrochloric acid, diluted 1:9, to the mark and mix. Depending on the content of iron is taken into a measuring flask with a capacity of 100 cmaliquote part of the tab.3.

Table 3

When the mass fraction of iron to 0.05% solution is evaporated to a volume of 10 cmand after cooling transferred in a volumetric flask with a capacity of 100 cm, to the solution was added 5 cmof the solution Vinokurova potassium-sodium, 20 cmsulfosalicylic acid solution, the solution was stirred, ammonia is added to obtain yellow coloring, then add 10 cmof ammonia in excess, made up to the mark with water, mix and after 30 min, measure the optical density of the solution in cuvette of 1 cm at 420 nm. Solution comparison is the solution of the reference experiment.

4.3.2. For alloys containing silicon in excess of 0.05%

A sample of alloy weighing 1 g is placed in a platinum Cup and dissolved by heating in 20 cmof nitric acid, diluted 1:1 with addition of 5 cmhydrofluoric acid and the solution was evaporated almost to dryness. Then twice more repeat the evaporation with 10 cmof nitric acid, diluted 1:1, heat, dilute with hot water to a volume of about 50 ml and after dissolution of dry residue and the solution transferred to a beaker with a capacity of 400 cm, dilute with water to 150 cmand then do as specified in clause 4.3.1.

4.3.3. Construction of calibration curve

In five out of six volumetric flasks with a capacity of 100 cmeach measure 1,0; 2,0; 3,0; 4,0 and 5,0 cmstandard solution, which corresponds to 0,1; 0,2; 0,3; 0,4 and 0,5 mg of iron. To all flasks add 5 cmof the solution Vinokurova potassium-sodium and then do as specified in clause 4.3.1. Solution comparison is the solution not containing iron.

According to the obtained values of optical densities and their corresponding grades of iron to build the calibration graph.

4.4. Processing of the results

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

,

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

 — the volume of the initial solution of the sample, cm;

 — volume aliquote parts of a solution of the sample, cm;

 — the weight of the portion,

4.4.2. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed the values given in table.2.

4.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (the reproducibility) shall not exceed the values specified in table.2.

4.4.2, 4.4.3. (Changed edition, Rev. N 2, 4).

4.4.4. The control accuracy of the analysis carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) copper-zinc alloys, approved GOST 8.315, or by additives, or by comparing the results obtained by another method in accordance with GOST 25086.

(Changed edition, Rev. N 4).

4.4.4.1−4.4.4.3. (Deleted, Rev. N 4).

5. ATOMIC ABSORPTION METHOD FOR DETERMINATION OF IRON

5.1. The essence of the method

The method is based on dissolving the sample in a mixture of hydrochloric and nitric acids and measuring the nuclear absorption of iron in the flame acetylene-air, using light with a wavelength of 248.3.

(Changed edition, Rev. N 3).

5.2. Apparatus, reagents and solutions

The atomic absorption spectrometer.

Lamp with hollow cathode for the iron.

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

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

A mixture of hydrochloric and nitric acids in the ratio 3:1.

Copper metal according to GOST 859.

The copper solution: 50 g of copper is dissolved in 400 cmof a mixture of nitric and hydrochloric acids in a 1:1 ratio. After dissolution the solution was transferred to a volumetric flask with a capacity of 500 cmand topped to the mark with water.

10 cmof the solution contains 1 g of copper.

The iron metal.

Standard solutions of iron.

Solution a: 1.0 g iron is dissolved in 25 cmof nitric acid, diluted 1:1, boiling removes oxides of nitrogen, the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, top up to the mark with water and mix.

1 cmof the solution contains 1 mg of iron.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, add 2 cmof nitric acid, diluted 1:1, made up to the mark with water and mix.

1 cmof a solution contains 0.1 mg of iron.

5.3. Analysis

5.3.1. A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 250 cmand dissolved by heating in 20 cmof a mixture of acids. The solution was transferred to a volumetric flask with a capacity of 100 or 250 cm,and topped to the mark with water. When the mass fraction of iron of more than 0.2% select aliquote part in accordance with the table.4; in a volumetric flask with a capacity of 100 cmadd 20 cmof a mixture of acid and add water to the mark.

Table 4

5.3.2. Preparation of the calibration solutions

In seven of the eight volumetric flasks with a capacity of 100 cmplaced 0,5; 1,0; 2,0; 4,0; 6,0; 8,0 and 10.0 cmof standard iron solution B, which corresponds to 0,05; 0,1; 0,2; 0,4; 0,6; 0,8 and 1.0 mg of iron. All flasks is poured 20 cmof a mixture of acid and add water to the mark.

5.3.3. Measure the atomic absorption of iron in solutions of the analyzed alloys and in the calibration solutions, recording the analytical signals. Use the flame of acetylene-air and the analytical line of 248.3 nm for iron.

According to the obtained values build the calibration graph.

5.3, 5.3.1−5.3.3. (Changed edition, Rev. N 3).

5.4. Processing of the results

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

,

where is the iron concentration in the sample solution, g/cm;

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

 — volume of the volumetric flask to prepare the final sample solution, cm;

 — weight of charge, g

.

5.4.2. The absolute discrepancies in the results of parallel measurements ( — convergence) must not exceed the values given in table.2.

(Changed edition, Rev. N 2, 4).

5.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (the reproducibility) shall not exceed the values specified in table.2.

(Changed edition, Rev. N 4).

5.4.4. The control accuracy of the analysis carried out according to State standard samples (GSO) or industry standard sample (CCA), or by standard samples of the enterprise (SOP) copper-zinc alloys, approved GOST 8.315, or by additives, or by comparing the results obtained by another method in accordance with GOST 25086.

(Changed edition, Rev. N 4).

5.4.4.1, 5.4.4.2. (Deleted, Rev. N 4).