GOST 2604.13-82

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  ГОСТ 2604.13-82

GOST 2604.13−82 Cast iron alloy. Methods for determination of aluminium (with Change No. 1)

GOST 2604.13−82

Group B09

INTERSTATE STANDARD

ALLOY CAST IRON

Methods for determination of aluminium

Alloy cast iron. Methods for determination of aluminium

ISS 77.080.10
AXTU 0809

Date of introduction 1984−01−01

Resolution of the USSR State Committee on standards of 16 December 1982, N 4777 date 01.01.84 established the introduction of

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

EDITION with Change No. 1, approved in April 1988 (I & C 7−88).


This standard specifies methods for the determination of aluminium:

gravimetric (when the mass fraction of aluminum from 0.1 to 40.0%) — with the separation of sodium fluoride from the slightly acidic solution, dissolving the precipitate of cryolite in the mixture of boric and hydrochloric acids and the deposition of aluminum autooksigenation;

the photometric (with a mass fraction of aluminum from 0.01 to 0.2%) — with the separation of the sodium hydroxide and formation of colored complex compounds of aluminum, chromazurol and polyvinyl alcohol at pH=6.2±0.4 mm.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 28473−90.

1.2. The error of the result of the analysis of () at p = 0.95 does not exceed the values given in table.2, when the conditions are met:

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

played in the standard sample, the value of the mass fraction of the element must not vary from certified more than acceptable (at a confidence level of 0.85) the value given in table.2.

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.

(Added, Rev. N 1).

2. GRAVIMETRIC METHOD

2.1. Apparatus, reagents and solutions

Hydrochloric acid by the GOST 3118−77.

Nitric acid GOST 4461−77.

Sulfuric acid GOST 4204−77 and diluted 1:4, 1:9, 1:100.

Hydrofluoric acid according to GOST 10484−78.

Ammonia water according to GOST 3760−79.

Ammonium citrate disodium, a solution of 0.4 g/cm.

Ammonium oxalate according to GOST 5712−78, saturated at room temperature the solution.

The solution of complexing agent: to 1 DMof the solution dosagedosage ammonium citrate is added to 1 DMof a saturated solution of ammonium oxalate and stirred.

Sodium fluoride according to GOST 4463−76, solutions of 0.005 and 0.035 g/cm.

Boric acid according to GOST 9656−75, saturated at room temperature the solution.

Potassium preservatory according to GOST 7172−76.

Oxalic acid according to GOST 22180−76.

Acetic acid GOST 61−75.

A mixture of boric and hydrochloric acids: 300 cmof a saturated solution of boric acid is added to 500 cmof hydrochloric acid and 1.2 DMwater. The solution was stirred.

Methyl red (indicator), alcohol solution of 0.001 g/cm.

8-hydroxyquinoline, ortho, imported, prepared as follows: 25 g of hydroxyquinoline dissolved in 50 cmof acetic acid. The solution is poured into a flask containing 950 cmof water, heated to 60 °C, stirred, cooled and filtered.

Ammonium acetate according to GOST 3117−78, a solution of 0.2 g/cm.

Fluid flushing: to 1 DMof warm water add 10 cmof a solution of ammonium acetate 0.2 g/cmand two drops of solution of ammonia.

Sec. 2. (Changed edition, Rev. N 1).

3. ANALYSIS

3.1. A portion of the cast iron depending on the mass fraction of aluminium is determined by the table.1.

Table 1

The weight of cast iron placed in a glass with a capacity of 250−300 cm, 25 cm pour thehydrochloric acid, the beaker cover watch glass, and heated moderately to dissolve the sample. Then, lightly sliding a watch glass, carefully, drop by drop, add nitric acid until the termination of foaming solution and the excess of 5−10 cm. The oxidized solution is heated to remove oxides of nitrogen. The solution was then cooled, carefully pour 10−15 cmof sulphuric acid and evaporated until the appearance of sulphuric acid fumes. The contents of the Cup is cooled, carefully poured 80−100 cmof water and heated to dissolve the salts.

After that the hour glass is washed with water and the precipitate of silicic acid is filtered in two filters «white ribbon». The filter residue is washed four or five times with hot sulfuric acid (1:100), collecting the filtrate and washings in a beaker with a capacity of 400 cm. Retain the filtrate (stock solution), and the filter with the sediment was placed in a platinum crucible, dried, incinerated and calcined at 900−1000 °C. the crucible with the precipitate is cooled, the residue moistened with 2−3 drops of water, add 2−3 cmof sulphuric acid, diluted 1:4, 3−5 cmhydrofluoric acid. The contents of the crucible carefully evaporated until vapours of sulphuric acid, is calcined at 900−1000 °C, cooled and the residue fused with 2−3 g of potassium peacemaking. The smelt is leached 20−30 cmof sulphuric acid (1:9) and the resulting solution was attached to the main solution.

Pour the ammonia solution until the appearance of stable precipitate hydroxides of the metals. Then cautiously, drop by drop, add sulfuric acid to dissolve the precipitate and the excess of it 4−5 drops.

After that, the solution was poured 25 cmof a solution of complexing agent, 60−80 cmof a solution of sodium fluoride 0.035 g/cmand stirred. After 20 min the precipitate of cryolite (with a small aluminum content, the precipitate is almost invisible in the solution, due to the close refractive index of the solution and crystals precipitate) is filtered by two filter «blue ribbon». The precipitate is then washed 10−15 times with a solution of sodium fluoride 0.005 g/cmand dissolved on the filter 50−70 cmboiling solution of a mixture of boric and hydrochloric acids, collecting the solution in a glass, which conducted the deposition. The filter was washed 5−6 times with hot water, collecting the washings in the same beaker.

To the obtained solution add 2−3 drops of methyl red solution, ammonia solution until the color of indicator from red to yellow and then drop by drop hydrochloric acid until the colour of the indicator to pink and add an excess of hydrochloric acid 4−5 drops.

Then alternately poured 20 cmof a solution of orthoxylene 10 cmof a solution of acetate of ammonium, again 25 cmof a solution of ammonium acetate and 5 cmof ammonia solution (after addition of each reagent a solution is mixed).

The contents of the beaker is heated to 60−70 °C and kept at this temperature for 10−15 min to coagulate the precipitate of oxyhydrate aluminum. Sediment is allowed to settle for 30 min at room temperature.

Sediment oxichinolina aluminium filter two filter «white ribbon» and washed 8−10 times with wash fluid. The filter with precipitate was placed in a porcelain crucible, previously ignited to constant mass and weighed. The filter with precipitate is poured 2−3 g of oxalic acid, dried, and incinerated at a temperature not higher than 400 °C and calcined at 1000−1100 °C to constant weight.

(Changed edition, Rev. N 1).

4. PROCESSING OF THE RESULTS

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

,

where is the mass of the precipitate of aluminium oxide in the sample, g;

 — sludge mass of aluminium oxide in a control experiment, g;

the weight of cast iron, g;

0,5292 — the ratio of aluminium oxide to aluminium.

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

Table 2

(Changed edition, Rev. N 1).

5. PHOTOMETRIC METHOD

Photometric method for determination of alloyed cast iron — according to GOST 12357−84.

(Added, Rev. N 1).