GOST 1953.7-79

• gost-19537-79.pdf (367.94 KiB)
  ГОСТ 1953.7-79

GOST 1953.7−79 Bronze tin. Methods for determination of iron (with Amendments No. 1, 2)

GOST 1953.7−79

Group B59

INTERSTATE STANDARD

BRONZE TIN

Methods of iron determination

Tin bronze.
Methods for the determination of iron

AXTU 1709

Date of introduction 1981−01−01

INFORMATION DATA

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

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 10.10.79 N 3899

3. The standard fully complies ST SEV 1534−79

4. REPLACE GOST 1953.7−74

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)

7. EDITION with Amendments No. 1, 2 approved in February 1983, August 1990 (IUS 6−83, 11−90)


This standard sets the photometric method for the determination of iron with the use of 1,10-phenanthroline or 2,2'-dipyridyl (from 0,0025% to 0.6%), a photometric method sulfosalicylic acid (0.01% to 0.6%) and atomic absorption method (with a mass fraction of iron from 0,0025% to 0.6%) in tin bronze according to GOST 5017, GOST GOST 613 and 614.

The standard fully complies ST SEV 1534−79.

(Changed edition, Rev. N 1, 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 25086 with the Supplement according to claim 1.1 GOST 1953.1.

(Changed edition, Rev. N 1, 2).

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

2.1. The essence of the method

The method is based on formation of a colored iron complex with 1,10-phenanthroline or 2,2'-dipyridylium after a preliminary distillation of tin in the form of tetrabromide and release of iron by coprecipitation with aluminum hydroxide.

2.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

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

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

Bromatologia acid according to GOST 2062.

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

Mix to dissolve, freshly prepared; prepared as follows: nine volumes bromatological acid is mixed with one volume of bromine.

The acid chloride.

Acetic acid according to GOST 61.

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

Sodium acetate according to GOST 199.

Bromine according to GOST 4109.

Alimohammadian alum (ammonium aluminium sulphate) according to GOST 4238, solution; is prepared as follows: 10 g of alum is dissolved in 1 DMof water with the addition of 10 cmof concentrated sulfuric acid.

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

1,10-fenantrolin hydrochloric acid, solution; is prepared as follows: 2.5 g of drug is dissolved by heating in a little water with a few drops of concentrated hydrochloric acid and dilute with water to 1 DM. Store the solution in a dark container.

2,2'-dipyridyl, solution; is prepared as follows: 1.5 g of 2,2'-dipyridyl dissolved by heating in a little water with a few drops of concentrated hydrochloric acid and dilute with water to 1 DM. Store the solution in a dark container.

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

A mixture of reagents, freshly prepared; one part of a solution of hydroxylamine hydrochloric acid is mixed with one part of solution of 1,10-phenanthroline or 2,2'-dipyridyl and three parts of the buffer solution.

Low carbon steel, a standard sample with a mass fraction of iron not less than 99.8%.

Iron oxide for HG.

Standard iron solution:

Solution A, prepared as follows: 0,5025 g of standard sample of low carbon steel or 0,7184 N 126 g of iron oxide 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 volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof solution B contains 0,000025 g of iron.

(Redrafted From

M. N 2).

2.3. Analysis

2.3.1. For bronzes containing no lead

Weighed bronze (see table.1) is placed in a beaker with a capacity of 300 cm, add 15 cmof the mixture to dissolve, cover with a watch glass and dissolved under heating. In case of incomplete dissolution, add dropwise bromine.

Table 1

Upon completion of the dissolution solution was poured to 20 cmof perchloric acid and evaporated with moderate heat to start the selection of thick white smoke and lightening solution. The solution was cooled, rinse walls of beaker and watch glass with water and repeat the evaporation until the appearance of dense white smoke of perchloric acid. The solution was cooled, rinse walls of beaker with water and heated to dissolve the salts. The solution is diluted with water to 200 cm, add 5 cmof the solution alimohammadian alum and ammonia before the transfer of copper in a soluble ammonia complex. The solution is heated and kept for 30 min at 60 °C for coagulation of the precipitate hydroxides of iron and aluminum. The precipitate was filtered off on a medium density filter and wash the beaker and precipitate 3−5 times with a solution of ammonia, a dilution of 1:50. The precipitate is dissolved on the filter in a 10 cmhot hydrochloric acid, diluted 1:1, collecting the solution in the beaker, which was carried out the precipitation of the hydroxide. The filter was washed 4−5 times with hot water. Repeat the precipitation, filtration and washing the precipitate hydroxides of iron and aluminum. The precipitate is dissolved in 10 cmof hot hydrochloric acid, diluted 1:1, collecting the solution in a glass, which made the deposition. The filter was washed 4−5 times with hot water.

When the mass fraction of iron in the alloy, up to 0.02% solution is evaporated to a volume of 30−40 cm, transferred to a volumetric flask with a capacity of 100 cm, add 25 cmof a mixture of reagents, made up to the mark with water and mix. After 30 min, measure the optical density of the solution in cuvette with thickness of absorbing layer 1 cm at a spectrophotometer at a wavelength of 510 nm or photoelectrocolorimeter with a green filter.

As a solution comparison using the solution in the reference experiment.

When the mass fraction of iron in excess of 0.02% solution is evaporated to a volume of 70−80 cmand transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water, mix. Aliquot part (see table.1) is placed in a volumetric flask with a capacity of 100 cm, top up with water to 50 cmand then do as stated

above.

2.3.2. For bronzes containing lead

Weighed bronze (see table.1) is placed in a beaker with a capacity of 300 cm, 15−30 cm, addthe mixture to dissolve, cover with a watch glass and dissolved under heating. In case of incomplete dissolution of the sample is added dropwise bromine. Upon completion of the dissolution solution was poured to 20 cmof perchloric acid and evaporated the solution at a moderate heat to start the selection, the dense white smoke of perchloric acid and clarification of the solution. The solution was cooled, rinse walls of beaker and watch glass with water and repeat the evaporation until the appearance of dense white smoke of perchloric acid.

The solution was cooled, rinse the walls of the beaker with a little water and heated to dissolve the salts. To the resulting solution was added to 100 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 sulfuric acid, diluted 1:100. The precipitate is discarded. To the filtrate add 5 cmalimohammadian solution of alum and then received, as indicated in claim 2.3.1.

2.3.3. Construction of calibration curve

In a volumetric flask with a capacity of 100 cmare placed sequentially: 0; 1,0; 2,0; 4,0; 6,0 and 8.0 cmof a solution of iron, add water to 50 cmand then do as described in claim 2.3.1.

Solution comparison is the solution not containing iron.

2.4. Processing of the results

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

,

where  — the amount of iron was found in the calibration schedule g;

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

2.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence for 3) specified in table.1A.

Table 1A

(Changed edition, Rev. N 2).

2.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (-an indicator of reproducibility) shall not exceed the values specified in table.1A.

2.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or by additives or by comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.

2.4.5. The photometric method is used in case of disagreement in assessing the quality of tin bronzes.

2.4.3−2.4.5. (Added, Rev. N 2).

3. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON WITH SULFOSALICYLIC ACID

3.1. The essence of the method

The method is based on the formation of trivalent iron with sulfosalicylic acid yellow complex compound and measurement of its optical density.

3.2. Apparatus, reagents and solutions

Photoelectrocolorimeter or spectrophotometer.

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

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

Bromatologia acid according to GOST 2062.

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

The acid chloride.

Sulfosalicylic acid, a solution of 200 g/DM.

Bromine according to GOST 4109.

Mix to dissolve, freshly prepared; prepared as follows: nine volumes bromatological acid is mixed with one volume of bromine.

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

Alimohammadian alum (ammonium aluminium sulphate) according to GOST 4238; prepared as follows: 10 g of alum is dissolved in 1 DMof water with 10 cmof concentrated sulfuric acid.

Low carbon steel, a standard sample with an iron content not less than 99.8%.

Iron oxide for HG.

Standard solutions of iron.

Solution A, prepared as follows: 0,5025 g of standard sample of low carbon steel or 0,7184 g of iron oxide 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 500 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.001 g of iron.

Solution B is prepared as follows: 10 cmof solution A is placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

1 cmof a solution contains 0.0001 g jelly

for.

3.3. (Deleted, Rev. N 2).

3.3.1. For bronzes containing no lead

The sample of bronze with a weight of 1 g was placed in a beaker with a capacity of 300 cmadd 30 cmof the mixture to dissolve, cover with a watch glass and dissolved under heating. In case of incomplete dissolution, add dropwise bromine. Upon completion of the dissolution sample solution was poured to 20 cmof perchloric acid and removed prior to the emergence of white smoke of perchloric acid and clarification of the solution. The solution was cooled, rinse watch glass and sides of beaker with water and repeat the evaporation until a white smoke of perchloric acid. Cool, rinse walls of beaker and watch glass with water and heated to dissolve the residue. The solution is diluted with water to 200 cm, add 5 cmof the solution alimohammadian alum and ammonia before the transfer of copper in a soluble ammonia complex. The solution is heated and kept for 30 min at 60 °C for coagulation of the precipitate hydroxides of iron and aluminum. The precipitate was filtered off on a medium density filter, the beaker and the precipitate was washed 3−5 times with a solution of ammonia, diluted 1:50. The precipitate is dissolved on the filter in a 10 cmhot hydrochloric acid, diluted 1:1, collecting the solution in the beaker, which was carried out the precipitation of the hydroxide. The filter was washed 4−5 times with hot water. Repeat the precipitation, filtration and washing the precipitate hydroxides of iron and aluminum. The precipitate is dissolved in 10 cmof hot hydrochloric acid, diluted 1:1, collecting the solution in a glass, which conducted the deposition and the filter was washed 4−5 times with hot water.

When the mass fraction of iron in the alloy up to 0.05% solution is evaporated to a volume of 30−40 cm, transferred to a volumetric flask with a capacity of 100 cm, flow 15 cmsulfosalicylic acid solution, the ammonia until yellow color and 3 cmin excess, made up to the mark with water and mix. Measure the optical density of the solution in a cuvette with a layer thickness of 1 cm on the spectrophotometer at a wavelength of 425 nm or photoelectrocolorimeter with a blue filter. Solution comparison is the solution of the blank experience.

When the mass fraction of iron in excess of 0.05% solution is evaporated to a volume of 70−80 cm, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. Aliquot part (see table.2) is placed in a volumetric flask with a capacity of 100 cm, top up with water to a volume of 50 cmand then do as above.

Table 2

3.3.2. For bronzes containing lead

The sample of bronze with a weight of 1 g was placed in a beaker with a capacity of 300 cmadd 30 cmto dissolve, cover with a watch glass and dissolved under heating. In case of incomplete dissolution, add dropwise bromine. Upon completion of the dissolution sample solution was poured to 20 cmof perchloric acid and evaporated the solution at a moderate heat to start the selection of thick white smoke and lightening solution. The solution was cooled, rinse walls of beaker and watch glass with water and repeat the evaporation until the appearance of dense white smoke of perchloric acid.

The solution was cooled, rinse walls of beaker and watch glass with water and heated to dissolve the residue. To the resulting solution was added to 100 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 sulfuric acid, diluted 1:100. The precipitate is discarded. To the filtrate add 5 cmalimohammadian solution of alum and then received, as indicated in paragraph 3.3.1.

(Changed edition, Rev. N 1).

3.3.3. For sequential determination of elements in one test portion for determination of iron in excess of 0.05% is used, the electrolyte, after separation of the copper. To do this in a volumetric flask with a capacity of 100 cmis taken aliquot part of the solution, equal to 50 cmwhen the mass fraction of iron from 0.05% to 0.25%, or 25 cmwhen the mass fraction of iron from 0.25% to 0.5%, add 15 cmsulfosalicylic acid solution and then act as described in section 3.3.1.

3.3.4. Construction of calibration curve

In a volumetric flask with a capacity of 100 cmare placed sequentially 0; 1,0; 2,0; 4,0 and 6,0 cmof a solution of iron, add 20 cmof water 15 cmsulfosalicylic acid solution and then act as described in section 3.3.1.

Solution comparison is the solution not containing iron.

3.4. Processing of the results

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

,

where  — the amount of iron was found in the calibration schedule g;

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

3.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence for 3) specified in table.1A.

(Changed edition, Rev. N 2).

3.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (-an indicator of reproducibility) shall not exceed the values specified in table.1A.

3.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or by additives or by comparison of the results obtained by atomic absorption method, in accordance with GOST 25086.

3.4.3, 3.4.4. (Added, Rev. N 2).

4. ATOMIC ABSORPTION METHOD FOR DETERMINATION OF IRON

4.1.The essence of the method

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

4.2. Apparatus, reagents and solutions

Atomic absorption spectrometer with a radiation source for iron.

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

Hydrochloric acid according to GOST 3118.

A mixture of acid: mix one volume of nitric acid with three volumes of hydrochloric acid.

Iron carbonyl or the State standard sample N 666−81П type C1.

The solution of iron: 0.1 g of iron was dissolved with heating in 10 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 1 DMand topped to the mark with water.

1 cmof the solution contains 0.0001 g of iron.

Copper according to the GOST 859.

The copper solution: 10 g of copper was dissolved with heating in 80 cmof nitric acid (1:1). The solution was transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark.

1 cmof the solution contains 0.1 g of copper.

4.3. Analysis

4.3.1. A portion of the bronze mass, given in table.3, is dissolved by heating in 10−20 cmof the mixture of acids. The solution was transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark.

Table 3

Measure the atomic absorption of iron in the flame of acetylene-air at a wavelength of 248.3 nm parallel to the calibration solutions.

4.3.2. Construction of calibration curve

In six of the seven volumetric flasks with a capacity of 100 cmis placed 0,5; 2,0; 4,0; 6,0; 8,0 and 10,0 cmstandard solution of iron. All flasks is poured specified in the table.3 the volume of the mixture of acids and standard copper solution and add water to the mark.

Measure the atomic absorption of iron, as stated in claim 4.3.1.

According to the obtained results build a calibration curve.

4.4. Processing of the results

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

,

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

- the solution volume of sample, cm;

- the weight of the portion of the sample,

4.4.2. Discrepancies in the results of parallel definitions should not exceed the values of permissible differences (- rate of convergence for 3) specified in table.1A.

4.4.3. Discrepancies in the results analysis, obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (D —index of reproducibility) shall not exceed the values specified in table.1A.

4.4.4. Control of accuracy of analysis results is carried out according to State standard samples of tin bronzes, re-approved by GOST 8.315, or by additives or by comparison of the results obtained photometric methods in accordance with GOST 25086.

Sec. 4. (Added, Rev. N 2).