GOST 11739.9-90

• gost-117399-90.pdf (226.46 KiB)
  ГОСТ 11739.9-90

GOST 11739.9−90 Alloys aluminium cast and wrought. Methods for determination of cadmium

GOST 11739.9−90

Group B59

STATE STANDARD OF THE USSR

ALLOYS ALUMINIUM CAST AND WROUGHT

Methods for determination of cadmium

Aluminium casting and wrought alloys.
Methods for determination of cadmium

AXTU 1709

Valid from 01.07.91
before 01.07.96*
_______________________________
* Expiration removed
Protocol 5−94 N Interstate Council
for standardization, Metrology and certification
(IUS N 11/12, 1994). — Note the manufacturer’s database.

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of aviation industry of the USSR

DEVELOPERS

V. G. Davydov, doctor of engineering. Sciences; V. A. Moshkin, PhD. tech. Sciences; G. I. Friedman, PhD. tech. Sciences; L. A. Tenyakova; M. N. Gorlova, PhD. chem. Sciences; O. L. Sikorska, PhD. chem. science; N. Perashvili

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 28.06.90 N 1961

3. The frequency of inspection — 5 years

4. REPLACE GOST 11739.9−78

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies the polarographic (with a mass fraction of cadmium from 0.005 to 1.0%) and atomic absorption (at a mass fraction of cadmium from 0.01 to 1.0%) methods for determination of cadmium.

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 25086 with the Supplement.

1.1.1. For the results analysis be the arithmetic mean of results of two parallel measurements.

2. POLAROGRAPHIC METHOD FOR THE DETERMINATION OF CADMIUM

2.1. The essence of the method

The method is based on dissolving the sample in hydrochloric acid and polarography of CD for the potential recovery from minus 0.5 to minus 0.9 In on the background of chloride-ammonia solution and a solution of sodium semitecolo.

Zinc, copper and Nickel do not interfere with the determination of cadmium. For the mass concentration of cadmium is less than 0.01% in the presence of copper at its mass fraction more than 1% of the latter are separated by electrolysis.

2.2. Apparatus, reagents and solutions

Polarograph universal or AC.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cmand a solution of 1:1, 1:9.

Nitric acid according to GOST 4204, a density of 1,35−1,40 g/cm, a solution of 1:1.

Hydrogen peroxide according to GOST 10929.

Ammonia water according to GOST 3760.

Ammonium chloride according to GOST 3773.

Sodium sanitarily according to GOST 195.

The solution of the polarographic background: 100 g of ammonium chloride and 50 g semitecolo sodium dissolved in 500 cmof hot water, once dissolved, pour the 100 cmof ammonia, cooled, top up with water to a volume of 1000 cmand mixed.

Aluminium GOST 11069* brand А999.
_______________
* On the territory of the Russian GOST 11069−2001, here and hereafter. — Note the manufacturer’s database.

A solution of aluminium: 10 g of aluminum is placed in a conical flask with a capacity of 500 cm, add 50 cmof water, then small portions of 300 cmof a hydrochloric acid solution (1:1) and dissolved under moderate heating. The solution was cooled, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

Cadmium GOST 22860* brand Кд000.
_______________
* On the territory of the Russian Federation GOST 22860−93, here and hereafter. — Note the manufacturer’s database.

Standard cadmium solution: 0.1 g of cadmium is placed in a conical flask with a capacity of 250 cm, 30 cm, pour thehydrochloric acid solution (1:1) and 10 cmof nitric acid solution. After dissolving, the solution is evaporated almost to dryness, then twice repeat the evaporation with 10 cmof hydrochloric acid. To the cooled residue add 100 cmof hydrochloric acid solution (1:9), cooled, transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

1 cmstandard solution contains 0,0001

g of cadmium.

2.3. Analysis

2.3.1. A portion of the sample mass according to table.1 is placed in a conical flask with a capacity of 250 cm, 30 cm, pour thehydrochloric acid solution (1:1) and dissolved under moderate heating. After the cessation of violent reaction add 2 cmof hydrogen peroxide and heating was continued until complete dissolution of the sample. The walls of the flask is washed with 10 cmof water and boil for 5 min.

Table 1

The cooled solution was transferred to volumetric flask with a capacity of 200 cmusing for washing the walls of the flask no more than 30 cmof water, carefully add 5 cmof ammonia, cooled, poured solution the polarographic background to the mark and mix. The solution was filtered through a paper filter into a dry conical flask.

2.3.2. A portion of the filtrate was placed in a cell with Donna polarography mercury and polarographic according to the instruction manual of the device in alternating current mode at a voltage of from minus 0.5 to minus 0.9 V.

2.3.3. The solution in the reference experiment is prepared according to claim 2.3.1 with all reagents used in the analysis.

2.3.4. Mass fraction of cadmium is calculated according to the calibration schedule.

2.3.5. Construction of calibration graphs

2.3.5.1. When the mass fraction of cadmium from 0.005 to 0.05% in seven volumetric flasks with a capacity of 200 cmis placed 50 cmof a solution of aluminum in six of them measure 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution, which corresponds to 0,00005; 0,0001; 0,0002; 0,0003; 0,0004; 0,0005 g of cadmium.

2.3.5.2. When the mass fraction of cadmium from 0.05 to 0.2 percent in seven volumetric flasks with a capacity of 200 cmis placed 25 cmof a solution of aluminum in six of them measure 2,5; 3,0; 4,0; 5,0; 7,5; 10,0 cmstandard solution, which corresponds to 0,00025; 0,0003; 0,0004; 0,0005; 0,00075; 0,001 g of cadmium.

2.3.5.3. When the mass fraction of cadmium from 0.2 to 1.0% in six volumetric flasks with a capacity of 200 cmis placed 10 cmsolution of aluminium, in five of them measure 4,0; 6,0; 10,0; 15,0; 20,0 cmstandard solution, which corresponds to 0.0004 inch; about 0.0006; 0,001; 0,0015; 0.002 g of cadmium.

2.3.5.4. All flasks (see PP.3.3.5.1, 3.3.5.2 and 3.3.5.3) pour 5 cmof ammonia and further arrive according to a PP.2.3.1 and 2.3.2.

Solutions not containing cadmium, are the solutions of the control experience in the construction of calibration curve.

According to the obtained values of the wave height and the corresponding mass of cadmium build the calibration graph.

2.4. Processing of the results

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

, (1)

where is the mass of cadmium in the sample solution found by the calibration schedule g;

 — the weight of the portion of the sample,

2.4.2. Discrepancies in the results must not exceed the values given in table.2.

Table 2

3. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF CADMIUM

3.1. The essence of the method

The method is based on dissolving the samples in hydrochloric acid in the presence of hydrogen peroxide and subsequent measurement of the atomic absorption of cadmium at a wavelength of 228,8 nm in the flame acetylene-air.

3.2. Apparatus, reagents and solutions

Spectrophotometer of atomic absorption with the source of cadmium.

Acetylene according to GOST 5457.

Hydrochloric acid according to GOST 3118, density of 1.19 g/cm, a solution of 1:1.

Nitric acid according to GOST 4461, density 1,35−1,40 g/cmand a solution of 1:1.

Hydrogen peroxide according to GOST 10929.

Nickel chloride according to GOST 4038, a solution of 1 g/DM.

Aluminium GOST 11069 brand А999.

A solution of aluminum 20 g/DM: 10 g of aluminum is placed in a beaker with capacity of 500 cm, add 50 cmof water and then small portions of 300 cmof a hydrochloric acid solution (1:1) and dissolve with a moderate heat, adding 1 cmof solution of chloride Nickel. The solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

Cadmium GOST 22860 brand Кд000.

Standard solutions of cadmium

Solution a: 0.5 g of cadmium is placed in a conical flask with a capacity of 250 cm, flow 10 cmof nitric acid, 25 cmhydrochloric acid solution and dissolved under moderate heating. The solution was 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 cadmium.

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

1 cmof solution B contains 0,00

01 g of cadmium.

3.3. Analysis

3.3.1. A portion of sample weighing 0.5 g is placed in a conical flask with a capacity of 250 cm, pour approximately 10 cmof water and then small portions of 25 cmof a solution of hydrochloric acid. The beaker cover watch glass, heat to completely dissolve the sample, add 3−5 drops of hydrogen peroxide and boil the solution for 3 min.

Watch glass and walls of the flask rinsed with water. The solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

3.3.2. When the mass fraction of silicon is less than 1% solution, if it is not transparent, was filtered through a dry filter medium density (white ribbon) in a beaker, discarding the first portions of the filtrate.

3.3.3. Depending on the mass fraction of cadmium according to table.3 select aliquot part of the solution, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Table 3

3.3.4. The solution in the reference experiment is prepared according to PP.3.3.1, .3.3.2 and 3.3.3 using is sample the sample the sample of aluminium.

3.3.5. Construction of calibration graphs

3.3.5.1. When the mass fraction of cadmium from 0.01 to 0.1% in seven volumetric flasks with a capacity of 100 cmpoured in 25 cmof a solution of aluminum in six of them measure 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution B, which corresponds to 0,00005; 0,0001; 0,0002; 0,0003; 0,0004; 0,0005 g of cadmium.

3.3.5.2. For the mass concentration of cadmium in excess of 0.1 to 1.0% in seven volumetric flasks with a capacity of 100 cmpour 2.5 cmof solution of aluminum in six of them measure 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution B, which corresponds to 0,00005; 0,0001; 0,0002; 0,0003; 0,0004; 0,0005 g of cadmium.

3.3.5.3. The solutions in flasks in PP.3.3.5.1 and 3.3.5.2 add 5 cmof hydrochloric acid, made up to the mark with water and mix.

3.3.6. The sample solution, solution control experience and solutions to build the calibration curve is sprayed into the flame of acetylene-air and measure the atomic absorption of cadmium at a wavelength of 228,8 nm.

According to the obtained values of atomic absorption and corresponding mass concentrations of cadmium build the calibration graph.

Mass concentration of cadmium in the sample solution and in the solution of control and experience determined by the calibration schedule.

3.4. Processing of the results

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

, (2)

where is the mass concentration of cadmium in the sample solution found by the calibration schedule, g/cm;

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

 — the volume of the sample solution, cm;

 — the weight of the portion of sample or the mass of the sample in the appropriate aliquote part of the sample solution, g

.

3.4.2. Discrepancies in the results must not exceed the values given in table.4.

Table 4