GOST 2604.14-82

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  ГОСТ 2604.14-82

GOST 2604.14−82 Cast iron alloy. Methods for determination of cobalt (with Amendments No. 1, 2)

GOST 2604.14−82

Group B09

INTERSTATE STANDARD

ALLOY CAST IRON

Methods for determination of cobalt

Alloy cast iron. Methods for determination of cobalt

ISS 77.080.10
AXTU 0809

Date of introduction 1984−01−01

INFORMATION DATA

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

DEVELOPERS

M. D. Rambus, T. A. Parkhomenko, G. N. Stein, T. A., Kalinchenko, Tn. Poltoratskaya

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 13.12.82 N 4718

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)

6. EDITION with Amendments No. 1, 2 approved in March 1986, April 1988, (IUS 6−86, 7−88)



This standard establishes photometric methods for determination of cobalt (at a mass fraction of from 0.02 to 3.0%) and atomic absorption method for the determination (when the mass fraction of from 0.005 to 5.0%) in the doped iron.

(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 28473.

1.2. The error of the result of the analysis of () at p = 0.95 does not exceed the limit given in table.2, 3, 5 under the conditions of:

the discrepancy between the results of two (three) parallel dimensions should not exceed (at p = 0.95) values are given in table.2, 3, 5;

played in the standard sample, the value of the mass fraction of the element must not vary from certified more than acceptable (at confidence probability of 0.95) of the values given in table.2, 3, 5.

The divergence of the two middle results of an analysis performed under different conditions (for example, when the control intralaboratory reproducibility) shall not exceed (at p = 0.95) values are given in table.2, 3, 5.

(Added, Rev. N 2).

2. The PHOTOMETRIC METHOD for the DETERMINATION of COBALT (0,02 to 0,5%)

2.1. The essence of the method — according to GOST 12353, div.3.

2.2. Apparatus, reagents and solutions — according to GOST 12353, div.3.

2.3. Analysis — according to GOST 12353, div.3 with the additions set out below.

2.3.1. A portion of the cast iron and the volume of hydrochloric acid to dissolve is determined depending on the mass fraction of cobalt in the table.1.

Table 1

2.3.2. Construction of calibration curve

Six glasses or flasks with a capacity of 250−300 cmis placed 0.5 g of carbonyl iron. In five glasses poured consistently 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution A, which corresponds to 0,1; 0,2; 0,3; 0,4; 0.5 mg of cobalt.

The sixth glass is used for the reference experiment. Next, with the contents of each beaker received as mentioned in paragraph 2.3.1.

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 cobalt in aliquote part of the solution to build calibration curve.

2.4. Processing of the results — according to GOST 12353, div.3 with the addition set out below.

2.4.1. Norms of accuracy and norms to control the accuracy of the mass fraction of cobalt are given in table.2.

Table 2

(Changed edition, Rev. N 2).

3. The PHOTOMETRIC METHOD for the DETERMINATION of COBALT (from 0.5 to 3.0%)

3.1. The essence of the method — according to GOST 12353, div.4.

3.2. Apparatus, reagents and solutions — according to GOST 12353, div.4.

3.3. Analysis — according to GOST 12353, div.4.

3.4. Processing of the results — according to GOST 12353, div.4 with the addition set out below.

3.4.1. Norms of accuracy and norms to control the accuracy of the mass fraction of cobalt are given in table.3.

Table 3

(Changed edition, Rev. N 2).

4. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF COBALT

4.1.The essence of the method

The method is based on dissolving the samples cast in the mixture of hydrochloric and nitric acids and measuring the degree of absorption of resonance radiation by free atoms of cobalt, produced as a result of spraying the test solution into the flame of air-acetylene at a wavelength of 240,7 nm or nm 252.1 bln.

4.2. Apparatus, reagents and solutions

Atomic absorption spectrophotometer fiery.

Lamp with hollow cathode for the determination of cobalt.

The cylinder with acetylene.

The compressor that provides the compressed air.

Acetylene according to GOST 5457.

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

Nitric acid according to GOST 4461.

Carbonyl iron, OS.h.

Cobalt metal according to GOST 123, grade KO.

Ascorbic acid, a solution of 0.1 g/cm.

Standard solutions of cobalt.

Standard solutions. A solution with A mass concentration of 0.001 g/cm: 0.5 g of cobalt metal was dissolved in a beaker with a capacity of 200 cmwhen heated at 20 cmof hydrochloric acid by adding 2 cmof nitric acid. The solution was evaporated to dryness, the residue is dissolved by heating in 20 cmof hydrochloric acid of 1:1. The solution was transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

Solution B with a mass concentration of 0.0002 g/cm: 20 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, pour 3−5cmof hydrochloric acid, made up to the mark with water and mix.

The solution with the mass concentration of 0.0001 g/cm: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, pour 3−5cmof hydrochloric acid, made up to the mark with water and mix.

(Amended And

ZM. N 2).

4.3. Analysis

4.3.1. In accordance with the enclosed instructions set up the spectrophotometer at a resonance line or 252.1 bln 240,7 nm. After switching on the gas flow and ignition of the burner spray water and set the zero of the instrument.

4.3.2. Determination of cobalt (0,005−0,1%)

The weight of cast iron weighing 1 g is placed in a beaker with a capacity of 200−300 cmand is dissolved by heating in 20 cmof salt and 5 cmof nitric acid. The solution was evaporated to dryness. To the dry residue poured 10 cmof hydrochloric acid and again evaporated to dryness. Then pour 5 cmof hydrochloric acid and evaporate the solution to wet salts, pour 1.5−2 cmof hydrochloric acid, 10 cmof water and heated to dissolve the salts.

Solution and the precipitate was transferred to a volumetric flask with a capacity of 50 cm, made up to the mark with water and mix. The solution is filtered through a dry filter into a dry conical flask with a capacity of 50 cm, discarding the first portions of the filtrate.

Atomic absorption cobalt measured at a wavelength of 240,7 nm.

To make amendments to the content of cobalt in chemicals through all stages of the analysis spend control experience. Is sprayed into the flame of the solution in the reference experiment, and then test solutions in order of increasing mass fraction of cobalt to obtain stable readings for each solution. Prior to introduction into the flame each of the analyzed solution is sprayed water to wash the system and check the zero point.

The value of the mass of cobalt in the sample solution found by the calibration schedule subject to amendments the reference experiment. The interval of concentrations of cobalt in the construction of calibration curve is recommended.

(Changed edition, Rev. N

2).

4.3.2.1. Construction of calibration curve

In eight glasses with a capacity of 200−300 cmwas placed 1.0 g of carbonyl iron. Seven of cups successively poured on 0,5; 1,0; 2,0; 4,0; 6,0; 8,0 and 10 cmstandard solution, which corresponds to 0,00005; 0,0001; 0,0002; 0,0004; 0,0006; 0,0008 and 0.001 g of cobalt within 50 cmof the analyzed solution. The eighth glass is used for the reference experiment.

Further analysis according to claim 4.3.2.

From the average value of the optical density of each solution is subtracted the average value of optical density in the reference experiment. On the found values of optical density and corresponding values of the mass of cobalt to build a calibration curve.

4.3.3. Determination of cobalt (0,1−5,0%)

The weight of cast iron depending on the mass fraction of cobalt is determined by the table.4.

Table 4

The weight of cast iron placed in a glass with a capacity of 200−300 cmand is dissolved by heating in 10 cmsalt and 3 cmof nitric acid. The solution was evaporated to dryness. To the dry residue poured 10 cmof hydrochloric acid and again evaporated to dryness. Then pour 3 cmof hydrochloric acid of 15 cmof water and heated to dissolve the salts.

The solution was filtered in a volumetric flask with a capacity of 100 cm, a glass filter and washed with water, the filter is discarded. To the filtrate poured 5 cmof ascorbic acid solution (when the sample of cast iron weighing 0.2 g) or 2.5 cm(when mounting cast iron weight 0.1 g), made up to the mark with water and mix.

Atomic absorption of cobalt measured in a flame of air-acetylene at a wavelength in accordance with table.4 depending on the mass fraction of cobalt.

Further analysis according to claim 4.3.2.

The value of the mass of cobalt in the sample solution found by calibration.

ku.

4.3.3.1. Construction of calibration curve

When the mass fraction of cobalt from 0.1 to 0.5% in seven glasses with a capacity of 250 cmis placed 0.2 g carbonyl iron, and six of them measure 1,0; 2,0; 4,0; 6,0; 8,0 and 10,0 cmstandard solution, which corresponds to 0,0001; 0,0002; 0,0004; about 0.0006; 0.0008 inch and 0.001 g of cobalt within 100 cmof the analyzed solution.

The seventh glass is used for the reference experiment.

When the mass fraction of cobalt, 0.5 to 1.0% in seven glasses with a capacity of 250 cmis placed 0.2 g carbonyl iron, and six of them measure 5,0; 6,0; 7,0; 8,0; 9,0 and 10,0 cmstandard solution B, which corresponds to 0.001; 0,0012; 0,0014; 0.0016 inch; 0,0018 and 0.002 g of cobalt within 100 cmof the analyzed solution.

The seventh glass is used for the reference experiment.

When the mass fraction of cobalt from 1.0 to 5.0% in six sample beakers with a capacity of 250 cmis placed 0.1 g carbonyl iron, and five of them measure 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution A, which corresponds to 0,001; 0,002; 0,003; 0,004 and 0,005 g of cobalt within 100 cmof the analyzed solution.

The sixth glass is used for the reference experiment.

In each glass pour 10 cmsalt and 3 cmof nitric acid. Further analysis are in accordance with clause 4

.3.3.

4.3.3, 4.3.3.1. (Changed edition, Rev. N 2).

4.4. Processing of the results

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

,

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

the weight of cast iron,

4.4.2. Norms of accuracy and norms to control the accuracy of the mass fraction of cobalt are given in table.5.

Table 5

(Changed edition, Rev. N 2).

Sec. 4. (Added, Rev. N 1).