GOST 22974.4-96

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  ГОСТ 22974.4-96

GOST 22974.4−96 fused welding Fluxes. Method for the determination of aluminium oxide

GOST 22974.4−96

Group B09

INTERSTATE STANDARD

FUSED WELDING FLUXES

Method for the determination of aluminium oxide

Melted welding fluxes.
Method of aluminium oxide 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 22974.4−96 introduced directly as state standard of the Russian Federation from January 1, 2000

4 REPLACE GOST 22974.4−85

1 Scope

This standard establishes titrimetric chelatometric method for the determination of aluminum oxide (with a mass fraction of aluminum oxide of 1 to 50%).

The essence of the method consists in formation at pH 5−6 colorless chelation of aluminium with Trilon B taken in excess. Excess Trilon B octarepeat solution of zinc acetate in the presence of the indicator dithizone or kylinalove orange to a sharp transition of color from yellow to crimson red. Hinder definition, the elements iron, manganese, titanium, zirconium and phosphorus are pre-separated.

2 Normative references

The present standard features references to the following standards:

GOST 61−75 acetic Acid. Specifications

GOST 1381−73 Methenamine technical. Specifications

GOST 2053−77 Sodium sulfurous 9-aqueous. Specifications

GOST 3117−78 Ammonium acetate. Specifications

GOST 3118−77 hydrochloric Acid. Specifications

GOST 3760−79 Ammonia water. Specifications

GOST 3773−72 Ammonium chloride. Specifications

GOST 4204−77 sulfuric Acid. Specifications

GOST 4234−77 Potassium chloride. Specifications

GOST 4328−77 Sodium hydroxide. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 5823−78 Zinc acetate 2-aqueous. Specifications

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

GOST 11069−74* Aluminium primary. Brand
________________
* On the territory of the Russian Federation GOST 11069−2001. Here and further. — Note the manufacturer’s database.

GOST 18300−87 ethyl rectified technical. Specifications

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 method of analysis according to GOST 22974.0.

4 Reagents and solutions

Nitric acid according to GOST 4461.

Sulfuric acid according to GOST 4204.

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

Acetic acid according to GOST 61.

Ammonia water according to GOST 3760, diluted 1:1.

Sodium hydroxide according to GOST 4328, solutions of the mass concentrations of 0.1 and 0.2 g/cm.

Ammonium acetate according to GOST 3117.

Ammonium chloride according to GOST 3773, solutions of the mass concentrations of 0.01 and 0.2 g/cm.

Potassium chloride according to GOST 4234.

Sodium sulfurous 9-aqueous GOST 2053, solution mass concentration of 0.025 g/cm.

Zinc acetate 2-water according to GOST 5823, solution with molar concentration of equivalent of 0.025 mol/DM: of 2.74 g of zinc acetate dissolved in 500 cmof water, pour 5 cmof acetic acid, transferred into a measuring flask with volume capacity of 1000 cm, adjusted to the mark with water and mix.

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.

The technical urotropine according to GOST 1381, solutions of the mass concentrations of 0.01 and 0.3 g/cm.

The technical rectified ethyl alcohol according to GOST 18300.

Methyl red (indicator), the solution of the mass concentration of 0.001 g/cm: 0.1 g of the indicator is dissolved in 60 cmof ethanol and add 40 cmof water.

Ditson (light), an alcoholic solution of the mass concentration of 0.0004 g/cm(stored in a dark place for no more than 2−3 days).

Selenology orange (indicator), is prepared as follows: 0.2 g of the indicator is triturated with 20 g of potassium chloride.

Paper of the Congo.

Universal indicator paper.

Congo red, solution mass concentration of 0.001 g/cm.

Buffer solution with a pH of 6.0: 500 g ammonium acetate dissolved in 1000 cmof water and add with constant stirring the glacial acetic acid to obtain a pH of 6.0 by universal indicator paper. If the solution is turbid, it is filtered.

Aluminium primary brands А999, A995 according to GOST 11069.

A standard solution of aluminum oxide: 0,5293 g of aluminium is dissolved in 30 cmof hydrochloric acid (1:1) under low heat. After complete dissolution of the aluminium solution is transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

A standard solution has a mass concentration of 0.001 g/cmof aluminum oxide.

The mass concentration of the solution Trilon B set by the standard solution of aluminium oxide.

Taken for 10 cmof a standard solution of aluminum oxide in three conical flasks with a capacity of 250 cm, poured in 40 cmwater, 10 cmof sodium hydroxide solution mass concentration of 0.1 g/cm, at 20 cmTrilon B and neutralize with hydrochloric acid (1:1) on the indicator Congo red to the transition of color from red to blue-violet. To the neutralised solution add 20 cmof a solution of acetate buffer, boil for 2−3 minutes, cool, add 2 cmof ditizone or 0,15−0,20 g kylinalove orange and titrated with a solution of acetate of zinc to the transition of color from yellow to crimson red.

The mass concentration of the solution Trilon B , g/cmof aluminum oxide, calculated by the formula

, (1)

where  — the weight of the portion corresponding to aliquots parts of a solution of aluminium oxide, g;

 — volume of solution Trilon B taken in excess, see;

 — the volume of solution of acetate of zinc consumed for back titration of the excess Trilon B, cm;

 — the ratio between the volume of the solution Trilon B and zinc acetate.

Set the ratio between the volume of solution Trilon B, and solution of acetate of zinc: three conical flasks with a capacity of 250 cmpour 10 cmof the solution Trilon B, 50 cmwater, 10 cmof sodium hydroxide solution mass concentration of 0.1 g/cm, neutralized with hydrochloric acid (1:1) for Congo red to the transition of color from red to blue-violet. Add 20 cmof a solution of acetate buffer, boil for 2−3 minutes, cool, then add 2 cmof ditizone or 0,15−0,20 g kylinalove orange and titrated with a solution of zinc acetate until the color of the solution in raspberry red.

The ratio between the volume of the solution Trilon B, and acetate of zinc is calculated by the formula

, (2)

where  — volume of solution Trilon B, cm;

 — the volume of solution of acetate of zinc, cm.

5 Preparing for analysis

5.1 Definition of Sesqui-oxides with ammonia

After the decomposition flux according to GOST 22974.1 50 cmof the solution was placed in a beaker with a capacity of 300−400 cm. If the decomposition of the flux was carried out by melting, the fluoride is removed as follows: pour 5 cmof nitric acid, carefully pour 10 cmof sulphuric acid and evaporate to dense fumes of sulfuric acid. The glass is cooled, washed wall with water and the evaporation repeated. The solution was cooled, poured 20 cmof hydrochloric acid (1:1), 150 cmof water and heated until complete dissolution of sulphate salts, then pour 20 cmof a solution of ammonium chloride mass concentration of 0.2 g/cm, heated to 70−80 °C, add 2−3 drops of methyl red indicator and ammonium hydroxide solution until the color changes of the indicator. The coagulation solution is heated for 3−5 min without boiling. The precipitate was filtered off on filter «white ribbon», washed 2−4 times with hot ammonium chloride solution the mass concentration of 0.01 g/cm, neutralized by ammonia methyl red. The precipitate sesquioxides oxides washed from the filter with hot water into a glass, which made the deposition, and dissolved in 20 cmof hot hydrochloric acid (1:1), heated to boiling and re-precipitated sesquioxides oxides with ammonia.

The precipitate was filtered off through the same filter and washed 5−6 times with hot ammonium chloride solution the mass concentration of 0.01 g/cm. The filtrate after separation of sesquioxides oxides collected in a volumetric flask with a capacity of 500 cmand used to determine the mass fraction of total calcium and magnesium oxide, and the residue for the determination of aluminum oxide

MINIA.

5.2 Department of Sesqui-oxides with hexamine

After the decomposition flux according to GOST 22974.1 50 cmof the solution was placed in a beaker with a capacity of 300−400 cm. If the decomposition of the flux was carried out by melting, then remove the fluoride as follows: pour 5 cmof nitric acid, carefully pour 10 cmof sulphuric acid and evaporate to dense fumes of sulfuric acid. The glass is cooled, washed wall with water and the evaporation repeated. The solution was cooled, poured 20 cmof hydrochloric acid (1:1), 150 cmof water, heated until complete dissolution of sulfate salts and is cooled. If the decomposition of the flux was carried out by acid, the solution diluted to 100 cmwith water, neutralized with ammonia solution on methyl red until the color of the solution from red to yellow. The excess ammonia is neutralized with 2−3 drops of hydrochloric acid (1:1). Dissolve the precipitate sesquioxides oxides and poured 20 cmof a solution of hexamine mass concentration of 0.3 g/cm. The coagulation solution is heated for 10−15 min until a temperature of 70−80 °C. the Precipitate was filtered off on filter «white ribbon», washed 4−5 times with hot solution of hexamine mass concentration of 0.01 g/cmand 4−5 times with hot water. The filtrate and washings are transferred into a measuring flask with a capacity of 500 cmand used to determine the mass fraction of total calcium and magnesium oxide, the precipitate for the determination of aluminium oxide.

6 analysis

The precipitate sesquioxides oxides washed into a glass, which made the deposition, the filter is washed with 20 cmof hydrochloric acid (1:1), then well washed with hot water. The total volume of the solution should be 60−70 cm. The solution is heated to complete dissolution of the precipitate, add 1 cmof a solution of sodium sulfide of the mass concentration of 0.025 g/cmand neutralized with hot sodium hydroxide solution mass concentration of 0.2 g/cmon the paper of the Congo with vigorous stirring until the color in the red, then pour in 30−40 cmof sodium hydroxide solution in excess. The solution is boiled for 3−4 min for the discharge of sediment (hydroxides of iron, titanium and zirconium) and cooled.

The contents of the beaker transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix well. The solution is filtered through dry filter «white ribbon» in a dry flask, discarding first portion of filtrate.

Aliquoting a portion of the filtrate and the volume of the added solution of Trilon B is determined depending on the mass fraction of aluminum oxide, as shown in table 1.


Table 1

The solution is neutralized with hydrochloric acid (1:1) for Congo red to the transition of color from red to blue-violet, poured 20 cmacetate buffer solution and boil for 2−3 min. the Solution was cooled, poured 2cmof ditizone or 0,15−0,20 g kylinalove orange and titrated with a solution of acetate of zinc to the transition of color from yellow to crimson red.

7 Processing of results

7.1 Mass fraction of aluminum oxide , %, is calculated by the formula

, (3)

where is the mass concentration of the solution Trilon B, g/cmof aluminum oxide;

 — the volume of the titrated solution of Trilon B taken in excess, see;

 — the amount of zinc acetate solution consumed for titration of the excess of the solution Trilon B, cm;

 — the ratio between the volume of the solution Trilon B, and acetate of zinc;

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

G.

7.2 Standards of accuracy and standards for monitoring the accuracy of determining the mass fraction of aluminum oxide are shown in table 2.


Table 2

Percentage