GOST 22536.8-87

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  ГОСТ 22536.8-87

GOST 22536.8−87 carbon Steel and unalloyed cast iron. Methods for determination of copper (with Change No. 1)

GOST 22536.8−87

Group B09

STATE STANDARD OF THE USSR

CARBON STEEL AND UNALLOYED CAST IRON

Methods for determination of copper

Carbon steel and unalloyed cast iron.
Methods for determination of copper

AXTU 0809

Valid from 01.01.88
to 01.01.98*
______________________________
* Expiration removed
Protocol N 7−95 Interstate Council
for standardization, Metrology and certification.
(IUS N 11, 1995). — Note
Note the manufacturer’s database.

INFORMATION DATA

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

PERFORMERS

D. K. Nesterov, PhD. tech. Sciences; S. I. Rudyuk, PhD. tech. science; N.N. Gritsenko, PhD. chem. Sciences (head of subject); V. F. Kovalenko, PhD. tech. Sciences; S. V. Spirina, PhD. chem. Sciences (head of subject); O. M. Kirzhner

2. APPROVED AND put INTO EFFECT by decision of the USSR State Committee for standards from 20.02.87 N 301

3. REPLACE GOST 22536.8−77

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. REPRINTING. December, 1987

The Change N 1, approved and put into effect by the decree of Gosstandart of the USSR from 28.03.90 N 659 from 01.10.1990.

The change made by the manufacturer of the database in the text IUS N 6, 1990


This standard specifies the extraction-photometric (at a mass fraction of copper 0,01−0,10%), photometric (mass fraction in copper 0,10−0,50%) and atomic absorption (at a mass fraction of copper 0,01−0,50%) methods for determination of copper in carbon steel and unalloyed cast iron.

Method for the determination of copper as ammonia complex are presented in the recommended application.

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 22536.0−87.

2. EXTRACTION-PHOTOMETRIC METHOD

2.1. The essence of the method

The method is based on the formation of ammonia in the solution is colored yellow complex compound of copper with sodium diethyldithiocarbamate, extraction of it with chloroform or carbon tetrachloride and measuring the light absorption of the extract at a wavelength of 436 nm.

2.2. Equipment and reagents

Spectrophotometer or photoelectrocolorimeter.

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

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

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

Ammonia water according to GOST 3760−79.

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

Chloroform according to GOST 20015−88 or carbon tetrachloride according to GOST 20288−74.

Diethyldithiocarbamate sodium GOST 8864−71, freshly prepared solutions with a mass concentration of 1 and 5 g/DM.

Carbonyl iron according to GOST 13610−79.

Ammonium disodium citrate according to GOST 3653−78, a solution with a mass concentration of 250 g/DM; prepared as follows: 250 cmof the solution placed in a separatory funnel with a capacity of 500 cm, add ammonia to pH 9 by universal indicator, 25 cmof a solution of sodium diethyldithiocarbamate with the mass concentration of 5 g/DM, 50 cmof chloroform and vigorously shaken for 2 min. Water and chloroform, the layers allowed to settle, the chloroform layer discarded.

Universal indicator paper.

Copper metal according to GOST 546−88, OS.h.

Copper sulphate standard solutions.

Solution a: 1 g of copper metal is dissolved by heating in 20 cmof nitric acid, diluted 1:1. After dissolution of the sample add 30 cmof sulphuric acid diluted 1:1, and the solution is evaporated to release vapors of sulfuric acid. The solution was cooled, the side of the Cup washed with water, poured 70−80 cmof water and dissolved salts when heated. The cooled solution is 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 copper.

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

1 cmof the solution contains 0.0001 g of copper.

(Changed edition, Rev. N 1).

2.3. Analysis

2.3.1. The weight of steel or cast iron weighing 0.5 g (when the mass fraction of copper from 0.01 to 0.04%) and 0.25 g (when the mass fraction of copper from 0.04 to 0.1%) were placed in a glass with a capacity of 250 cm, and dissolved in 30 cmof sulphuric acid, diluted 1:4 with a moderate heat, covered with a glass watch glass. After dissolution, are added dropwise nitric acid until the termination of foaming solution, boil until it is lightening, then evaporated to the appearance of sulphuric acid fumes and cooled. Salt is dissolved in 50−60 cmof water when heated, washing watch glass and sides of beaker, transfer the cooled solution into a measuring flask with a capacity of 100 cm, made up to the mark with water and mix. Part of the solution filtered through a dry filter into a dry flask, discarding first portion of filtrate.

Aliquot part equal to 10 cm, placed in a beaker with a capacity of 100 cm, flow 10 cmof a solution of citrate of ammonium, 10 cmof Trilon B solution, mix and add ammonia to pH 9 by universal indicator paper.

The solution was transferred to a separatory funnel with a capacity of 100 cm, washing the walls of the beaker with water, add 5 cmof a solution of sodium diethyldithiocarbamate with the mass concentration of 1 g/DM, mix and add 10 cmof chloroform (or carbon tetrachloride). The solution in the separating funnel vigorously shaken for 2 min. Water and chloroform, the layers allowed to settle and decanted after separation of the lower chloroform layer in a dry volumetric flask with a capacity of 25 cm, filtering through cotton. The separating funnel aqueous solution was added to 5 cmof chloroform and repeat the extraction, drain the chloroform layer into the same flask. The volume of the solution in the flask is poured chloroform (or carbon tetrachloride) to the mark and mix.

Optical density of the solution measured immediately after extraction on a photoelectrocolorimeter with a filter having maximum transmission in the range 400−450 nm, or spectrophotometer at a wavelength of 436 nm. As a solution the comparison used the chloroform. The thickness of the absorbing layer of the cell is chosen so to obtain the optimal value of optical density.

Simultaneously with the execution of the analysis carried out control experience for contamination of reagents.

From the values of absorbance of each test solution subtract the value of optical density in the reference experiment.

Mass of copper find the schedule for the calibration or by comparison with a standard sample.

(Changed edition, Rev. N 1).

2.3.2. Construction of calibration curve

Seven of cups with a capacity of 250 cmis placed sample of carbonyl iron, corresponding to the linkage sample. Six of them poured 0,5; 1,0; 1,5; 2,0; 2,5; 3,0 cmstandard solution B, which corresponds to 0,00005; 0,0001; 0,00015; 0,00020; 0,00025; 0,00030 g of copper. The seventh glass is used for the reference experiment. All the glasses are poured at 30 cmof sulphuric acid, diluted 1:4, and further receives, as described in Chapter 2.3.1.

On the found values of optical density and corresponding weight values of copper to build the calibration graph. Allowed construction of calibration curve in the coordinates: the optical density is the mass fraction of copper.

(Changed edition, Rev. N 1).

2.4. Processing of the results

2.4.1. Mass fraction of copper in percent is calculated by the formula

,

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

 — the weight of the portion,

2.4.2. Norms of accuracy and norms to control the accuracy of the mass fraction of copper in the table.

(Changed edition, Rev. N 1).

3. PHOTOMETRIC METHOD

3.1. The essence of the method

The method is based on formation of yellow colored complex compound of copper with sodium diethyldithiocarbamate in ammoniacal medium (pH 8,5−9,0) and measuring light absorption of the resulting complex at a wavelength of 453 nm.

3.2. Equipment and reagents

Instrument and reagent according to claim 2.2 with additions:

nitric acid GOST 4461−77 or GOST 11125−78 diluted 1:3;

sodium pyrophosphate according to GOST 342−77, a solution with a mass concentration of 50 g/DM;

gelatin food according to GOST 11293−78, a freshly prepared solution with a mass concentration of 5 g/DM: 0.5 g gelatin pour 100 cmof water and left for 2 h. the solution was Then heated while stirring until complete dissolution of the sample;

polyvinyl alcohols according to normative-technical documentation, an aqueous solution with a mass concentration of 2 g/DM.

3.3. Analysis

3.3.1. The weight of steel or cast iron with a mass of 0.25 g is placed in a beaker with a capacity of 100 cm, flow 20 cmof nitric acid, diluted 1:3, and dissolved by heating. Once dissolved, pour 5 cmof hydrochloric acid and the solution evaporated to dryness. The dry residue moistened with 15 cmof hydrochloric acid, poured 10 cmof water and heated until complete dissolution of salts. The cooled solution was transferred to volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. In the analysis of cast irons or in the case of precipitation of silicic acid solution is filtered through dry filter «white ribbon», discarding first portion of filtrate.

In two volumetric flasks with a capacity of 100 cmis placed aliquote part of the solution to 10 cm, is poured into each flask 20 cmwater 20 cma solution of sodium pyrophosphate, 10 cmof ammonia. The solutions were stirred and cooled, then poured on 10 cmgelatin or polyvinyl alcohol in one flask of 10 cmsolution of sodium diethyldithiocarbamate with the mass concentration of 5 g/DM. The solutions were topped up to the mark with water and mix. If steel or cast iron contains Nickel in the amount of 0.3−0.5%, before adding a solution of sodium diethyldithiocarbamate in each volumetric flask pour 5 cmof the solution Trilon B.

Optical density of the solution measured after 5 minutes on a photoelectrocolorimeter with a filter having maximum transmission in the range of 400−480 nm or on a spectrophotometer at a wavelength of 453 nm. As a solution comparison using the solution prepared without the addition of sodium diethyldithiocarbamate. The thickness of the absorbing layer of the cell is chosen so to obtain the optimal value of optical density.

Simultaneously with the execution of the analysis carried out control experience for contamination of reagents.

From the values of absorbance of each test solution subtract the value of optical density in the reference experiment.

Mass of copper find the schedule for the calibration or by comparison with a standard sample.

3.3.2. Construction of calibration curve

Six glasses with a capacity of 100 cmis placed 0.25 g of carbonyl iron, five of them poured standard solution B in an amount of 2,5; 5,0; 7,5; 10,0; 12,5 cm, which corresponds to 0,00025; 0,00050; 0,00075; 0,00100; 0,00125 g of copper. The sixth glass is used for the reference experiment. All the glasses are poured at 30 cmof nitric acid, diluted 1:3, and further receives, as described in Chapter 3.3.1.

On the found values of optical density and corresponding weight values of copper to build the calibration graph. Allowed construction of calibration curve in the coordinates: the optical density is the mass fraction of copper.

3.4. Processing of the results

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

,

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

 — the weight of the portion,

3.4.2. Norms of accuracy and norms of accuracy control of determination of mass fraction of copper in the table.

(Changed edition, Rev. N 1).

4. ATOMIC ABSORPTION METHOD

4.1. The essence of the method

The method is based on measuring the degree of absorption of resonance radiation by free atoms of copper, formed as a result of spraying the test solution in a flame air-acetylene.

4.2. Equipment and reagents

Atomic absorption spectrophotometer fiery.

Lamp with hollow cathode for the determination of copper.

The compressor supplying compressed air, or compressed air.

Acetylene according to GOST 5457−75.

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

Nitric acid GOST 4461−77 or GOST 11125−84 and diluted 1:1.

Carbonyl iron according to GOST 13610−79.

Copper metal according to GOST 546−79, OS.h.

Copper nitrate, in standard solutions:

Solution a: 1 g of copper metal is dissolved by heating in 20 cmof nitric acid, diluted 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 cmof the solution contains 0.001 g of copper.

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 cmof a solution contains 0.0001 g of copper.

4.3. Preparation for assay

The device is prepared in accordance with the enclosed instructions. Set the spectrophotometer at a resonance line of 324,7 nm.

After switching on the gas flow and ignition of the burner spray water and set the zero readings.

4.4. Analysis

4.4.1. The weight of steel or cast iron weighing 1 g is placed in a beaker with a capacity of 100 cmand dissolved in 15 cmof hydrochloric acid and 5 cmof nitric acid. The solution was evaporated to dryness, cool, add 4 cmof hydrochloric acid 20−30 cmof water and heated to dissolve the salts. The cooled solution is transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix. In the analysis of cast irons or in the case of precipitation of silicic acid solution is filtered through dry filter «white ribbon», discarding first portion of filtrate.

When the mass fraction of copper up to 0.10% determination of copper is carried out directly from the resulting solution. When the mass fraction of copper in excess of 0.10% is taken aliquot part of the solution is equal to 20 cm, placed in a volumetric flask with a capacity of 100 cm, pour 4 cmof hydrochloric acid, made up to the mark with water and mix. For preparation of the null solution in a volumetric flask with a capacity of 100 cmis placed 4 cmof hydrochloric acid, made up to the mark with water and mix. At the same time under the same conditions, a solution of the reference experiment, for which 1 g of iron carbonyl was placed in a beaker with a capacity of 100 cmand is carried out through all stages of the analysis.

The solutions were sprayed in order of increasing absorption, starting from the zero solution. Before spraying each solution is sprayed water to wash the system and check the zero point.

From the values of absorbance of each test solution subtract the value of optical density in the reference experiment.

Mass of copper found by the calibration schedule.

4.4.2. Construction of calibration curve

In six volumetric flasks with a capacity of 100 cmplaced 1,0; 3,0; 5,0; 6,0; 7,0; 10,0 cmstandard solution B, which corresponds to 0,0001; 0,0003; 0,0005; 0,0006; 0,0007; 0,0010 g of copper. The seventh flask is used for the reference experiment. All flasks are poured by 4 cmof hydrochloric acid, made up to the mark with water and mix. Then do as specified in clause 4.4.1.

On the found values of optical density and corresponding weight values of copper to build the calibration graph.

4.5. Processing of the results

4.5.1. Mass fraction of copper () in percent is calculated by the formula

,

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

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

4.5.2. Norms of accuracy and norms of accuracy control of determination of mass fraction of copper in the table.

(Changed edition, Rev. N 1).

APPLICATION (recommended). THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF COPPER AS AMMONIA COMPLEX FOR THE MASS CONCENTRATION OF 0.10 TO 0.50%

APP
Recommended

1. The essence of the method

The method is based on formation of blue coloured complex compounds of copper with ammonia (= 675 nm).

2. Equipment and reagents

Spectrophotometer or photoelectrocolorimeter.

Nitric acid GOST 4461−77 or GOST 11125−84 diluted 1:2.

Carbonyl iron according to GOST 13610−79.

Ammonium neccersarily according to GOST 20478−75 and a solution with a mass concentration of 150 g/DM.

Ammonia water according to GOST 3760−79.

Copper metal of high purity according to GOST 546−79.

Standard solution of copper sulphate: 1 g of copper metal is dissolved by heating in 25−30 cmof nitric acid, diluted 1:1, add 25 cmof sulphuric acid diluted 1:1, and the solution evaporated until the appearance of sulphuric acid fumes. After cooling the salt is dissolved in water, transfer the solution into 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 copper.

3. Analysis

3.1. The weight of steel or cast iron weighing 1 g is placed in a conical flask with a capacity of 100 cm, was dissolved with heating in 30 cmof nitric acid, diluted 1:2, and boil the solution until complete removal of nitrogen oxides. To the hot solution is poured 10 cmof the solution naternicola ammonium and boil for 3 min. In the presence of chromium and Nickel add dry neccersarily ammonium in an amount of 3−5 g.

The solution was cooled, transferred to a volumetric flask with a capacity of 100 cmand gently added in small portions with constant stirring to 40 cmof ammonia.

The contents of the flask are cooled, diluted to the mark with water and mix thoroughly.

Allowed to settle the bulk of the sediment and filter the solution through dry filter «white ribbon» in a dry flask. The first portion of the filtrate discarded. Optical density of the solution is measured on a photoelectrocolorimeter with a filter having maximum transmission in the range of 650−700 nm or on a spectrophotometer at a wavelength of 675 nm. A solution of comparison used water. The thickness of the absorbing layer is selected so the cell images to obtain the optimum value of optical density. Simultaneously with the execution of the analysis carried out control experience for contamination of reagents.

From the values of absorbance of each test solution subtract the value of optical density in the reference experiment.

Mass of copper find the schedule for the calibration or by comparison with a standard sample.

3.2. Construction of calibration curve

In six conical flasks with a capacity of 100 cmplaced 1 g of carbonyl iron, five of them add 1,0; 2,0; 3,0; 4,0; 5,0 cmstandard solution, which corresponds to 0,001; 0,002; 0,003; 0,004; 0.005 g of copper. Sixth bulb is used for the reference experiment. Poured into the flask at 30 cmof nitric acid, diluted 1:2, and do as above. A solution of comparison used water. On the found values of optical density and corresponding weight values of copper to build the calibration graph. Allowed construction of calibration curve in the coordinates: the optical density is the mass fraction of copper.

4. Processing of the results

4.1. Mass fraction of copper () in percent is calculated by the formula

,

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

 — the weight of the portion,

4.2. Norms of accuracy and norms of accuracy control of determination of mass fraction of copper in the table.

(Changed edition, Rev. N 1).