GOST 26473.3-85

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  ГОСТ 26473.3-85

GOST 26473.3−85 Alloys and alloys based on vanadium. Methods for determination of iron (with Change No. 1)

GOST 26473.3−85

Group B59

STATE STANDARD OF THE USSR

ALLOYS AND MASTER ALLOYS BASED ON VANADIUM

Methods of iron determination

Vanadium base alloys and alloying elements. Methods for determination of iron

AXTU 1709

Valid from 01.07.86
to 01.07.91*
_______________________________
* Expiration removed
by the decree of Gosstandart of the USSR from 14.05.91 N 679
(IUS N 8, 1991). — Note the manufacturer’s database.

DEVELOPED by the Ministry of nonferrous metallurgy of the USSR

PERFORMERS

Yu. A. Karpov, E. G. Nembrini, V. G., Miscreants, V. V. Nedler, V. M. Mikhailov, L. G. Agapova, G. N. Andrianov, A. V. Antonov, V. D. Dozen, M. A. Desyatkova, T. I. Kirillova, L. I. Kirsanov, I. E. Korepin, V. A. Orlova, N. Rasnitsyn, N. Suvorova, N. L. Tomasev, M. W. Schmidt, L. N. Filimonov

INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

Member Of The Board Of A. P. Snurnikov

APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on standards of 25 March 1985, N 751

The Change N 1, approved and put into effect by the Decree of the USSR State Committee on management of quality and standards from 14.05.91 N 676 from 01.01.92

Change No. 1 made by the manufacturer of the database in the text IUS N 2, 1990


This standard sets the photometric method for the determination of iron (0.1 to 3%) with 1,10-phenanthroline, photometric method for the determination of iron (from 0.1 to 10%) sulfosalicylic acid and a method of chelatometric determination of iron (5 to 10%) in alloys and master alloys based on vanadium, the contents of related components which are shown in table.1.

Table 1

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 26473.0−85.

2. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON WITH 1,10-FENANTROLINA

The method is based on reaction of formation of colored complex compounds of iron with 1,10-phenanthroline in acidic environment (pH 3.5−5.0) and fotomaterialy the color of the solution.

2.1. Apparatus, reagents and solutions

Type photoelectrocolorimeter FEK-56.

Analytical scale.

Libra technical.

Muffle furnace with thermostat, providing a temperature of 1000 °C.

Tile electric.

Volumetric flasks with a capacity of 50, 100, 250 and 1000 cm.

Microburette with a capacity of 10 cmwith a scale division of 0.02 cm.

Pipettes with a capacity of 5 cmwith divisions.

Measuring beakers with a capacity of 25 and 100 cm.

Glasses chemical glass with a capacity of 250 and 400 cm.

Funnels, glass, conical with a diameter of 50 mm.

The quartz crucibles high capacity of 40 cm.

The crucible of porcelain or platinum.

Obestochennye paper filter «white ribbon» with a diameter of 70 mm.

Desiccator with calcium chloride.

Calcium chloride (fused).

Sulfuric acid GOST 4204−77, diluted 1:1, and the solution of concentration 1 mol/DM.

Hydrochloric acid by the GOST 3118−77, diluted 1:1.

Nitric acid GOST 4461−77 diluted 1:1.

Potassium preservatory according to GOST 7172−76.

Tartaric acid according to GOST 5817−77, solution concentration of 250 g/DM.

1,10-fenantrolin, solution concentration 1.25 g/DM, is prepared as follows: 1.25 g of 1.10-phenanthroline was dissolved with heating in 500 cmof water with a few drops of sulfuric acid diluted 1:1, cooled, neutralized with sodium acetate solution on the indicator paper «the Congo» until the color of the paper from blue to lilac-pink, dilute with water to 1 DM. Store the solution in a dark container.

Paper display «of the Congo».

Sodium acetate 3-water according to GOST 199−78, a solution of concentration 500 g/DM.

Hydroxylamine hydrochloride according to GOST 5456−79, solution concentration 100 g/DM.

Ammonia water according to GOST 3760−79.

Iron metal has been restored.

Alum salesonline.

Allowed the preparation of a standard iron solution using different starting materials: gentoomaniac alum (series A) and iron metal (series B).

Series A

Standard solution of iron, containing about 1 mg/cmiron (solution a): 8,635 g gentoomaniac alum dissolved in water containing 10 cmof concentrated sulfuric acid (if dissolution is slow, the solution is heated). The cooled solution was transferred to volumetric flask with a capacity of 1 DM, adjusted to the mark with water, mix.

Accurate mass concentration of iron set by gravimetric method: in a glass with a capacity of 400 cmpipetted aliquot part (50 or 100 cm) of a standard solution of iron (A), heated to boiling and carefully adding ammonia, precipitated ferric hydroxide. After heating for 20−30 min sediment allowed to settle and filtered through a medium density filter «white ribbon» placed in a conical funnel, washing the filter cake and the beaker several times with hot water.

The washed residue was placed in a weighed porcelain or platinum crucible, dried, incinerated and calcined in a muffle furnace at 800−900 °C for 30 minutes, cool in desiccator, weigh. The calcination and weighing is repeated until obtaining constant weight.

At the same time through all stages of the analysis spend control experience (for contamination control reagents).

Mass concentration () mg/cmstandard solution of iron (solution A) is calculated according to the formula

,

where is the mass of the precipitate of iron oxide, mg;

 — the mass of sediment in the reference experiment, mg;

0,6996 — the ratio of iron oxide to iron;

 — aliquote the volume of a standard solution, cm.

Solution acontaining about 0.1 mg/cm(100 g/cm) iron, prepared by diluting solution Awith water 10 times.

A solutioncontaining about 0.01 mg/cm(10 µ g/cm) iron, prepared by diluting solution Awith water to 10 times a day use.

Series B

Standard solution of iron, containing 0.1 mg/cm(100 g/cm) iron (solution B): 0.1 g of recovered iron or piano wire is dissolved in 80 cmof hydrochloric acid diluted 1:1, transferred into a volumetric flask with a capacity of 1 DMand bring to mark with water.

Solution Bcontaining 0.01 mg/cm(10 µ g/cm) iron, prepared by dilution of a solutionwith water in 10 times a day use.

(Changed edition, Rev. N 1).

2.2. Podgot

starte analysis

2.2.1. For vanadium alloys and alloys with a mass fraction of zirconium of more than 1% of chromium more than 30% of the portion of the sample weighing 0.1 g was placed in a quartz crucible, add 3−4 g of persulfate potassium, a few drops of concentrated sulphuric acid and fused in a muffle at 800−900 °C to produce a clear float. The smelt is dissolved by heating in 25 cmof sulphuric acid diluted 1:1, the solution was transferred to volumetric flask with a capacity of 100 cm, cooled and adjusted to the mark with water.

2.2.2. For vanadium alloys and alloys with a mass fraction of niobium or tungsten, more than 1% of the portion of the sample weighing 0.1 g was placed in a quartz crucible, add 3−4 pyrosulphate potassium, a few drops of concentrated sulphuric acid and fused in a muffle at 800−900 °C to produce a clear float.

The smelt is dissolved by heating in 20 cmof a solution of tartaric acid, the solution transferred to a volumetric flask with a capacity of 100 cm, cooled, adjusted to the mark with water.

2.2.3. For vanadium alloys and alloys with a mass fraction of chromium is less than 30 percent and not containing tungsten, niobium, zirconium, a portion of the sample weighing 0.2 g was placed in a conical flask with a capacity of 250 cm, add 10 cmsulphuric acid diluted 1:1, and 5 cmof nitric acid diluted 1:1, and heated until complete dissolution of the sample the sample, then while continuing the heating to release of sulfuric acid vapors for 1−2 minutes the cooled solution on the walls of the flask poured 50 cmof water transfer the solution into a volumetric flask with a capacity of 100 cm, cooled and adjusted to the mark with water.

2.3. Analysis

2.3.1. For determining iron in two volumetric flasks with a capacity of 50 cmis taken equal aliquote part of the solution from 1 to 5 cm, containing 5−60 micrograms of iron, pour 1 cmof a solution of hydroxylamine, 5 cmof water and neutralized with a solution of sodium acetate until the color of the indicator paper «Congo» from blue to lilac-pink. In one of the flasks poured 10 cmof a solution of 1,10-phenanthroline, stirring after each addition of the reagent.

After 10−15 minutes the solutions was adjusted to the mark with water and measure their optical density on the photoelectrocolorimeter using a filter with maximum transmittance at a wavelength of ~510 nm and cuvette thickness of the light absorbing layer 30 mm in comparison to simultaneously prepared solution containing all the reagents except 1, 10-phenanthroline, «zero» solution containing all reagents except the standard iron solution.

Simultaneously with the analysis of a series of samples through all stages of the analysis spend control experience (for contamination control reagents). The value of the optical density of the solution in the reference experiment shall not exceed 0,03, otherwise necessary to change the reagents.

From the value of the optical density of the sample solution is subtracted the value of the optical density of the solution in the reference experiment.

Find weight of iron on the calibration schedule for the computed value of optical density.

(Changed edition, Rev. N 1).

2.3.2. Construction of calibration curve

In a volumetric flask with a capacity of 50 cmis injected from microburette 0,5; 1,0; 2,0; 3,0; 4,0; 5,0 and 6.0 cmof a standard solution of iron (solution Aor B), which corresponds to 5, 10, 20, 30, 40, 50 and 60 µg of iron. Pour 1 cmof a solution of hydroxylamine, 5 cmof water and a solution of sodium acetate until the color changes of the indicator paper «Congo» from blue to lilac-pink. Pour 10 cmof a solution of 1,10-phenanthroline for 10 minutes was adjusted to the mark with water (colored solutions are stable for a long period of time).

Measure the optical density of solutions on the photoelectrocolorimeter using a filter with maximum transmittance at a wavelength of ~510 nm and cuvette thickness of the light absorbing layer 30 mm in comparison to simultaneously prepared a «zero» solution containing all reagents except the standard iron solution.

On the found values of optical density and corresponding mass of iron to build a calibration curve

.

2.4. Processing of the results

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

,

where is the mass of iron was found in the calibration schedule, mcg;

 — volume of the volumetric flask, cm;

 — aliquotes volume of the solution taken for the determining, cm;

 — the weight of the portion of the sample,

2.4.2. The values of permissible differences are listed in table.2.

Table 2

(Changed edition, Rev. N 1).

3. PHOTOMETRIC METHOD FOR DETERMINATION OF IRON WITH SULFOSALICYLIC ACID

The method is based on reaction of formation of colored complex compounds of iron (III) with sulfosalicylic acid in an ammonia environment (pH 8−10) and fotomaterialy the color of the solution.

3.1. Apparatus, reagents and solutions

Type photoelectrocolorimeter FEK-56.

Analytical scale.

Libra technical.

Tile electric.

Volumetric flasks with a capacity of 100, 250 cm.

Pipettes with a capacity of 2.5 cmwith divisions.

Pipettes with a capacity of 10 cmwith no divisions.

Microburette with a capacity of 5 cmwith a scale division of 0.02 cm.

Measuring beakers with a capacity of 25 and 100 cm.

Knob glass conical with a diameter of 30 mm.

The obezvolennyh paper filter «white ribbon» with a diameter of 70 mm.

Glasses chemical glass with a capacity of 400 cm.

Sulfuric acid GOST 4204−77, diluted 1:1.

Nitric acid GOST 4461−77 diluted 1:1.

Sulfosalicylic acid 2-water according to GOST 4478−78, solution concentration of 200 g/DM.

Ammonia water according to GOST 3760−79 diluted 1:1.

Standard solution of iron, containing 0.1 mg/cm(100 g/cm) iron solution aor Bprepared according

claim 2.1.

3.2. Preparation for assay

A portion of the sample weighing 0.5−1 g were placed in a glass with a capacity of 400 cm, 30 cm pournitric acid, diluted 1:1, heated to dissolve the sample, poured 20 cmof sulphuric acid diluted 1:1, continuing the heating to release of sulfuric acid vapors for 1−2 minutes the cooled solution on the walls of the flask poured 100−150 cmof water and heated to dissolve the salts.

Solution and the precipitate was filtered through a medium density filter «white ribbon» placed in a conical funnel, washed precipitate with the filter several times with hot water. The filtrate and the washings collected in a volumetric flask with a capacity of 250 cm, cooled and adjusted to the mark with water (stock solution).

The sediment used (if necessary) for determination of silicon GOST 26473.4−85. The basic solution can be used (if necessary) for determination of molybdenum GOST 26473.6−85, titanium GOST 26473.8−85, vanadium and chromium GOST 26473.10−85, zirconium and aluminum according to GOST 26473.11−85.

3.3. Analysis

3.3.1. For the determination of iron in a volumetric flask with a capacity of 100 cmis taken aliquot part of the solution (2 to 10 cm) containing 50−400 µg of iron pour 10 cmsulfosalicylic acid solution, 15 cmof ammonia solution and adjusted to the mark with water.

After 20 minutes, measure the optical density of the solution on the photoelectrocolorimeter using a filter with maximum transmittance at a wavelength of ~430 nm and a cuvette with the thickness of the light absorbing layer of 20 mm in relation to the solution in the reference experiment, which is carried out through all stages of the analysis along with an analysis of a series of samples.

The mass of iron found by the calibration schedule.

3.3.2. Construction of calibration curve

In a volumetric flask with a capacity of 100 cmis injected from microburette 0,5; 1,0; 2,5; 3,5 and 4,0 cmstandard solution of iron (solution Aor B), which corresponds to 50; 100; 250; 350 and 400 mcg of iron, diluted to 10 cmof water, poured 10 cmsulfosalicylic acid solution, 15 cmof ammonia solution and adjusted to the mark with water.

After 20 minutes, measure the optical density of the solution on the photoelectrocolorimeter using a filter with maximum transmittance at a wavelength of ~430 nm and a cuvette with the thickness of the light absorbing layer of 20 mm in relation to the simultaneously cooked «zero» solution containing all reagents except the standard iron solution.

On the found values of optical density and corresponding mass of iron to build a calibration curve

.

3.4. Processing of the results

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

,

where is the mass of iron was found in the calibration schedule, mcg;

 — capacity volumetric flasks, cm;

 — volume aliquote part, cm;

 — the weight of the portion of the sample,

3.4.2. The values of permissible differences are listed in table.3.

Table 3

(Changed edition, Rev. N 1).

4. CHELATOMETRIC METHOD FOR DETERMINATION OF IRON

The method is based on complexometric direct titration of iron in acidic solution with indicator — sulfosalicylic acid, after separation of iron together with aluminum, manganese, vanadium, chromium, molybdenum by precipitation with ammonia in presence of hydrogen peroxide.

4.1. Apparatus, reagents and solutions

Tile electric.

Analytical scale.

Libra technical.

Volumetric flasks with a capacity of 100 cm, 1 DM.

Pipettes with a capacity of 20 cmwithout the divisions.

Conical flasks with a capacity of 250 cm.

Burettes capacity 10 cmwith a scale division of 0,05 cm.

Measuring beakers with a capacity of 25, 100 and 250 cm.

Glasses chemical glass with a capacity of 200 and 400 cm.

Funnels, glass, conical.

Obestochennye paper filter «white ribbon» or «yellow ribbon».

Universal indicator paper.

Sulfuric acid GOST 4204−77 and diluted 1:3.

Nitric acid GOST 4461−77 and diluted 1:1.

Hydrochloric acid by the GOST 3118−77, diluted 1:1.

Hydrogen peroxide according to GOST 10929−76.

Ammonium chloride according to GOST 3773−72, solution concentration of 100 and 20 g/DM.

Ammonia water according to GOST 3760−79 diluted 1:1.

Wash solution: to 1000 cmof solution of ammonium chloride concentration of 20 g/DMadd 2−3 cmof hydrogen peroxide and 2 cmof ammonia.

Technical methenamine according to GOST 1381−73.

Selenology orange solution with a concentration of 1 g/DM.

Sulfosalicylic acid, 2-water according to GOST 4478−78, solution concentration 100 g/DM.

Zinc, granulated.

Zinc chloride, solution concentration of 0.05 mol/DM: 3,2690 g of zinc metal is placed in a beaker with a capacity of 200 cm, 20−30 cm, moistened withwater and poured in small portions 25 cmhydrochloric acid solution, diluted 1:1. The solution is evaporated to wet salts, salt dissolved in water, transferred to a volumetric flask with a capacity of 1 DM, adjusted to the mark with water.

Trilon B (disodium salt of Ethylenediamine-N, N, N', N'-tetraoxane acid, 2-water) according to GOST 10652−73, solution concentration of 0.05 mol/DM: 18.6 g Trilon B dissolved in water in low heat. The solution was then cooled, filtered in a volumetric flask with a capacity of 1 DM, adjusted to the mark with water.

(Changed edition, Rev. N 1).

4.1.1. Establish the relation between the solutions of Trilon B and zinc chloride (): in a conical flask with a capacity of 250 cmpipetted 20 cmof a solution of zinc chloride, poured 80 cmof water, neutralized with ammonia to a pH of 3.5−4.0 on the universal indicator paper, add 1.5−2 g of hexamine, 2−3 drops of solution kylinalove orange and titrated with a solution of Trilon B till the transition of color from crimson to yellow.

The ratio () of Trilon B and solutions of chloride of zinc is calculated by the formula

,

where 20 is the volume of solution of zinc chloride taken for titration, cm;

 — volume of solution Trilon B, spent on titration, sm.

4.2. Analysis

A portion of the sample weighing 1 g is placed in a beaker with a capacity of 400 cm, 120 cm pouredsulphuric acid, diluted 1:3, heated to boiling and the hot solution poured 20−25 cmof concentrated nitric acid. If the sample dissolves it is bad, then poured another 15−20 cmof nitric acid, heated to complete dissolution of the sample is evaporated to a volume of 50−70 cm, cooled to room temperature, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water.

In a conical flask with a capacity of 250 cmpipetted 20 cmof the resulting solution, poured 30 cmwater, 5 cmof concentrated sulfuric acid, 20−25 cmof hydrogen peroxide, 25−30 cmof a solution of ammonium chloride; heat to a boil and carefully add the ammonia, diluted 1:1, weak to the point of view of smell (control the pH value of the solution near 7 on the universal indicator paper), and continue the boiling for a few minutes.

Provide sediment to koagulirovat, quickly filter the solution and precipitate through a paper filter «yellow ribbon» placed in a conical funnel, and the precipitate washed on the filter 6−7 times a hot flushing solution.

The filter with precipitate was placed in a flask in which was conducted the deposition, poured 20 cmof hydrochloric acid, heated until the precipitate has fully dissolved, pour the 100 cmof water, neutralized with ammonia to a pH of about 2 (universal indicator paper), heat the solution to 60−70 °C, poured 2 cmsulfosalicylic acid solution and titrated the iron (III) solution of Trilon B (adding Trilon B solution slowly, stirring carefully) until the color of dark red

in yellow.

4.3. Processing of the results

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

,

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

0,002792 — mass concentration of the solution Trilon B, expressed in g/cmiron;

 — the ratio of the volume of the solution Trilon B and zinc chloride;

 — capacity volumetric flasks, cm;

 — aliquotes volume of the solution taken for titration, cm;

 — the weight of the portion of the sample,

4.3.2. The values of permissible differences are listed in table.4.

Table 4