GOST 22974.6-96

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  ГОСТ 22974.6-96

GOST 22974.6−96 fused welding Fluxes. Methods for determination of iron (III)oxide

GOST 22974.6−96

Group B09

INTERSTATE STANDARD

FUSED WELDING FLUXES

Methods for determination of iron (III)oxide

Melted welding fluxes. Methods of iron oxide (III) determination

ISS 77.040
AXTU 0809

Date of implementation 2000−01−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 72; the Institute of electric them. E. O. Paton of NAS of Ukraine

SUBMITTED to the State Committee of Ukraine for standardization, Metrology and certification

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 9 dated April 12, 1996)

The adoption voted:

3 Resolution of the State Committee of the Russian Federation for standardization and Metrology, dated April 21, 1999 N 134 inter-state standard GOST 22974.6−96 introduced directly as state standard of the Russian Federation from January 1, 2000

4 REPLACE GOST 22974.6−85

1 Scope

This standard sets the photometric method for the determination of iron (III) oxide at a content of from 0.1 to 10%, titrimetric chelatometric method for the determination of iron (III) oxide at a content of from 0.5 to 20% and the atomic absorption method for the determination of iron (III) oxide at a content of from 0.1 to 10%.

2 Normative references

The present standard features references to the following standards:

GOST 199−78 Sodium acetate 3-water. Specifications

GOST 3118−77 hydrochloric Acid. Specifications

GOST 3760−79 Ammonia water. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 4478−78 sulfosalicylic Acid 2-water. Specifications

GOST 5456−79 Hydroxylamine hydrochloride. Specifications

GOST 5457−75 Acetylene, dissolved and gaseous. Specifications

GOST 10652−73 Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid 2-water (Trilon B)

GOST 22974.0−96 fused welding Fluxes. General requirements for methods of analysis

GOST 22974.1−96 fused welding Fluxes. Methods of flux decomposition

3 General requirements

General requirements for methods of analysis GOST 22974.0.

4 Photometric method for the determination of iron (III)oxide

4.1 the essence of the method

Ions of iron (III) form sulfosalicylic acid in the ammonia environment with a pH of 8−12 complex compound colored in yellow color. In the presence of a large excess sulfosalicylic acid titanium ions to give colourless complexes. The effect of manganese compounds is eliminated by addition of a solution of hydrochloric acid hydroxylamine. Optical density of the solution is measured on a photoelectrocolorimeter with a blue color filter at a wavelength of 430 nm.

4.2 Equipment, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Nitric acid according to GOST 4461.

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

Ammonia water according to GOST 3760.

Sulfosalicylic acid 2-water according to GOST 4478, solution mass concentration of 0.2 g/cm.

Hydroxylamine hydrochloride according to GOST 5456, solution mass concentration of 0.1 g/cm.

Paper of the Congo.

Iron carbonyl.

Standard solutions of iron (III) oxide.

Solution a: 0,6995 g carbonyl iron is dissolved by heating in 30 cmof hydrochloric acid (1:1). After complete dissolution of the sample solution is oxidized with a few drops of nitric acid, boil to remove oxides of nitrogen, cooled, transferred into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix. The solution has a mass concentration of 0.0001 g/cmof iron (III)oxide

.

4.3 analysis

4.3.1 After the decomposition flux according to GOST 22974.1 aliquot part of the solution is 10−50 cmdepending on the mass fraction of iron (III) oxide in the flux is placed in a volumetric flask with a capacity of 100 cm, flow 10 cmof a solution of hydrochloric acid hydroxylamine, 10 cmsulfosalicylic acid solution, neutralized with ammonia on the paper of the Congo, add an excess of ammonia 10 cm, adjusted to the mark with water and mix. After 5−10 min, measure the optical density on the spectrophotometer at a wavelength of 430 nm or photoelectrocolorimeter with a blue filter in a cell with thickness of the absorbing layer 30 mm.

Solution comparison is the solution of the control experiment through all stages of the analysis.

Mass of iron oxide (III) find the calibration schedule.

4.3.2 Construction of calibration curve

In ten volumetric flasks with a capacity of 100 cmmaking 1; 2; 4; 6; 8; 10; 12; 14; 16 and 18 cmstandard solution B, which corresponds to 0,0001; 0,0002; 0,0004; 0,0006; 0,0008; 0,0010; 0,0012; 0,0014; 0,0016; 0,0018 g of iron (III) oxide. In the eleventh flask used for the solution preparation comparison, make a 10 cmwater. Pour 10 cmsulfosalicylic acid solution and then conduct analysis 4.3.1.

4.4 Processing of results

Mass fraction of iron oxide (III) , %, is calculated by the formula

, (1)

where  — the mass of iron (III) oxide, was found in the calibration schedule g;

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

4.5 Norms of accuracy and norms control the accuracy of determining the mass fraction of iron (III) oxide are given in table 1.


Table 1

Percentage

5 Titrimetric chelatometric method for the determination of iron (III) oxide for fluxes that do not contain zirconium oxide

5.1 the essence of the method

The method is based on titration of ions of trivalent iron with a solution of Trilon B at pH 1−2. As an indicator used sulfosalicylic acid.

5.2 Solutions and reagents

Sodium acetate 3-water according to GOST 199, solution mass concentration of 0.5 g/cm.

Sulfosalicylic acid 2-water according to GOST 4478, solution mass concentration of 0.2 g/cm.

Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid 2-water (Trilon B) according to GOST 10652, solution with molar concentration of equivalent of 0.025 mol/DM: 4.65 g Trilon B dissolved in 300 cmof water. The solution was filtered into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

Universal indicator paper.

Standard solution of iron oxide prepared according to 4.2.

5.3 analysis

After the decomposition flux according to GOST 22974.1 aliquot part of the solution of 25−50 cmwere placed in a glass with a capacity of 250−300 cm, surging solution of sodium acetate and set of universal indicator paper pH 1−2, pour 10−15 drops of sulfosalicylic acid, heated to 60−70 °C and slowly titrated with a solution of Trilon B before transition of colouring from red-crimson to lemon-yellow.

5.4 processing of the results

Mass fraction of iron oxide (III) , %, is calculated by the formula

, (2)

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

 — mass concentration of the solution Trilon B, expressed in g/cmiron oxide;

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

Mass concentration of Trilon B set according to the standard solution And iron oxide (III) as specified in 5.3.

5.5 the Norms of accuracy and norms control the accuracy of determining the mass fraction of iron oxide are shown in table 1.

6 Atomic absorption method for the determination of iron (III)oxide

6.1 the essence of the method

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

6.2 Apparatus, reagents and solutions

Atomic absorption spectrophotometer with flame atomizer.

Lamp with hollow cathode for the determination of iron.

Acetylene, dissolved and gaseous technical GOST 5457.

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

Standard solution of iron (III) oxide prepared as described in 4.2.

6.3 Preparation for analysis

Before operation, set the spectrophotometer at a resonance line of 248.3 nm.

6.4 analysis

After the decomposition flux according to GOST 22974.1 aliquot part of the solution is 5−25 cm(depending on the mass fraction of iron oxide (III) is transferred to a volumetric flask with a capacity of 100 cm, add 5 cmof hydrochloric acid (1:1), made up to the mark with water and mix.

Is sprayed into the flame of the solution in the reference experiment, and then analyze the solution.

Prior to introduction into the flame of each solution is sprayed water to wash the system and check the zero point.

6.5 Construction of calibration curve

In ten volumetric flasks with a capacity of 100 cmplaced 0,5; 1,0; 2,0; 3,0; 4,0; 5,0; 6,0; 7,0; 8,0 and 9.0 cmstandard solution B, which corresponds to 0,00005; 0,00010; 0,00020; 0,00030; 0,00040; 0,00050; 0,00060; 0,00070; 0,00080 and 0,00090 g of iron oxide (III), add 5 cmof hydrochloric acid (1:1), made up to the mark with water and mix.

The solutions were sprayed in order of increasing concentration (absorption). Before spraying each solution is sprayed water.

6.6 processing of the results

6.6.1 From the average value of absorbance of each of the analyzed solutions, the average value is subtracted absorption in the reference experiment.

Mass (g) of iron (III) oxide in the test solution found by the calibration schedule.

6.6.2 Mass fraction of iron oxide (III) , %, is calculated by the formula

, (3)

where  — the mass of iron (III) oxide, was found in the calibration schedule g;

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

6.7 Standards of accuracy and standards for monitoring the accuracy of determining the mass fraction of iron oxide are shown in table 1.