GOST 2604.8-77

• gost-26048-77.pdf (208.88 KiB)
  ГОСТ 2604.8-77

GOST 2604.8−77 alloy Cast iron. Methods for determination of Nickel (with Amendments No. 1, 2)

GOST 2604.8−77

Group B09

INTERSTATE STANDARD

ALLOY CAST IRON

Methods for determination of Nickel

Alloy cast iron. Methods for determination of nickel

ISS 77.080.10
AXTU 0809

Date of introduction 1978−01−01

The decision of the State standards Committee of the USSR Council of Ministers dated 22 March 1977, N 680 date of introduction is established 01.01.78

Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)

REPLACE GOST 2604−44 in part of sec. VII

EDITION with Amendments No. 1, 2 approved in December 1982, April 1985 (IUS 3−83, 7−85).


This standard applies to alloy cast iron and sets the photometric method for the determination of Nickel (from 0.1 to 1.0%), gravimetric method (0.1 to 25.0%) and atomic absorption method (from 0.1 to 15.0%).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 28473−90.

2. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF NICKEL WITH DIMETHYLGLYOXIME

2.1.The essence of the method


The method is based on formation of colored in brown-red complex compound of Nickel with dimethylglyoxime (=420−430 nm) in alkaline medium in the presence of an oxidant — ammonium naternicola. The optimum pH range 8−10. The interfering influence of iron, chromium, copper, and other elements can be eliminated by addition of potassium-sodium Vinokurova. When the mass fraction of copper of more than 2%, the definition should be conducted by the gravimetric method.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Hydrochloric acid by the GOST 3118−77, diluted 1:1 and 1:4.

Nitric acid GOST 4461−77.

Potassium-sodium vinocity according to GOST 5845−79, 20% solution.

Sodium hydroxide according to GOST 4328−77, 5% solution.

Ammonium neccersarily according to GOST 20478−75, 3% freshly prepared solution.

Dimethylglyoxime according to GOST 5828−77, 1% solution in 5% strength sodium hydroxide solution, prepared as follows: 10 g dimethylglyoxime dissolved in 1 DM5% sodium hydroxide solution.

Carbonyl iron according to GOST 13610−79, 0,2% solution; prepared as follows: in a conical flask with a capacity of 100 cmis placed 0.5 g carbonyl iron, poured 25 cmhydrochloric acid diluted 1:1, and moderately heated until complete dissolution of the sample. Then carefully poured drop by drop nitric acid until the termination of foaming and boil to remove oxides of nitrogen. The contents of the flask cooled, transferred to a volumetric flask with a capacity of 250 cm, made up to the mark with water and mix.

Nickel metal according to GOST 849−97, marks N-0, standard solutions.

The solution And the mass concentration of 0.0001 g/cm: 0.1 g of metallic Nickel is dissolved with moderate heating in 20 cmof hydrochloric acid diluted 1:4 in the presence of a few drops of nitric acid. After complete dissolution of the sample solution was boiled to remove oxides of nitrogen, cooled, transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

Solution B with a mass concentration of 0,00001 g/cm: 10 cmstandard solution And placed in a volumetric flask with a capacity of 100 cmand dilute to the mark with water.

(Changed edition, Rev. N

2).

2.3. Analysis

2.3.1. The weight of cast iron weighing 0.2 g was placed in a conical flask with a capacity of 100 cm, flow 25 cmhydrochloric acid diluted 1:1, and moderately heated until complete dissolution of the sample. Then, carefully poured drop by drop nitric acid until the termination of foaming and boil to remove oxides of nitrogen.

Silicic acid, and graphite was filtered, the filter «white ribbon» in a volumetric flask with a capacity of 100 cm, the sediment is washed on the filter two or three times with water, cooled, made up to the mark with water and mix. Aliquote parts of a solution of 5 cmis placed into two volumetric flasks with a capacity of 100 cm.

In each flask sequentially poured (with stirring) for 10 cmof 20% aqueous solution Vinokurova of potassium-sodium at 10 cm,5% sodium hydroxide solution and 10 cm3% solution of ammonium naternicola.

One flask pour 10 cmof a 1% strength solution dimethylglyoxime. The solution in the second flask (without dimethylglyoxime) is solution comparisons. After 2−3 min. to both flasks add water to the mark and mix.

Optical density of the solution is measured after 5−7 min. on a photoelectrocolorimeter with a blue color filter at a wavelength of 420−430 nm.

Mass fraction of Nickel in the cent find for the calibration.

ku.

2.3.2. Construction of calibration curve

Aliquote parts of a solution of carbonyl iron for 5 cmplaced in six volumetric flasks with a capacity of 100 cm.

In ten volumetric flasks poured consistently 1,0; 2,0; 3,0; 4,0; 5,0; 6,0; 7,0; 8,0; 9,0; 10,0 cmstandard solution B, which corresponds to 10; 20; 30; 40; 50; 60; 70; 80; 90; 100 micrograms of Nickel in relation to the original mounting of cast iron weighing 0.2 g and aliquote parts of a solution of 5 cm.

In each flask sequentially poured (with stirring) for 10 cmof 20% aqueous solution Vinokurova of potassium-sodium at 10 cm,5% sodium hydroxide solution and 10 cm3% solution of ammonium naternicola.

All flasks is poured on a 10 cm1% solution dimethylglyoxime. After 2−3 minutes add water to the mark and mix.

Measure the optical density of the solution in 5−7 minutes on a photoelectrocolorimeter with a blue color filter at a wavelength of 420−430 nm.

A solution of comparison is the solution in the flask containing carbonyl iron, carried through the entire course of the analysis, to which add the same reagents as the sample, but not containing Nickel.

On the found values of optical density of the solutions and their corresponding weight fractions of Nickel to build a calibration curve.

(Changed edition, Rev. N 2

).

2.4. Processing of the results

2.4.1. Mass fraction of Nickel in the cent find for the calibration schedule.

2.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level =0.95 does not exceed the values specified in paragraph 3.4.2.

(Changed edition, Rev. N 1).

3. GRAVIMETRIC METHOD FOR THE DETERMINATION OF NICKEL BY PRECIPITATION OF AN DIMETHYLGLYOXIME

3.1.The essence of the method

The method is based on deposition of Nickel dimethylglyoxime in labumiem solution (pH 8−10). The interfering influence of iron, chromium, manganese and other elements can be eliminated by addition of tartaric acid. The precipitate of Nickel dimethylglyoximate dried and weighed.

3.2. Reagents and solutions

Hydrochloric acid by the GOST 3118−77, diluted 1:1 and 1:100.

Nitric acid GOST 4461−77.

Sulfuric acid according to GOST 4204−77.

Hydrofluoric acid according to GOST 10484−78.

Potassium preservatory according to GOST 7172−76.

Ammonium chloride according to GOST 3773−72, 10% solution.

Tartaric acid according to GOST 5817−77, 50% solution.

Ammonia water according to GOST 3760−79.

Rectified ethyl alcohol GOST 18300−87.

Dimethylglyoxime according to GOST 5828−77, 1% alcoholic solution; prepared as follows: 10 g dimethylglyoxime dissolved in 750 cmof alcohol, poured 250 cmof hot water and stirred.

Universal indicator paper.

3.3. Analysis

The weight of cast iron depending on the mass fraction of Nickel is determined by the table.1.

Table 1

The sample is placed in a beaker with capacity of 500 cm, cover with a watch glass and dissolved under moderate heating in 30 cmof hydrochloric acid, adding dropwise nitric acid until the termination of foaming. The solution was evaporated to dryness. To the dry residue poured 10 cmof hydrochloric acid and again evaporated to dryness. Then pour 10−20 cmof hydrochloric acid and the contents of the beaker is heated to dissolve the salts. The solution is poured 80−100 cmof hot water heated to 80−90 °C, wash watch glass with water, filtered off the precipitate of silicic acid and graphite on the filter «white ribbon» with the addition of paper pulp. The filter cake was washed several times with hydrochloric acid, diluted 1:100. The filtrate and washings retain (stock solution). The filter with precipitate was placed in a platinum crucible, dried, incinerated and calcined at 1000−1100 °C. Then the crucible with residue was cooled. The residue moistened with 2−3 drops of water, add 3−4 drops of sulfuric acid, 3−4 cmhydrofluoric acid and cautiously evaporate the contents of the crucible to remove vapors of sulfuric acid. The residue in the crucible is fused with 2−3 g of potassium peacemaking, leached with water under heating and added to the main solution.

To the obtained solution pour 5 cmof a 10% solution of ammonium chloride, 20−40 cm,50% tartaric acid solution and add ammonia solution to pH 8−10 by universal indicator, and then hydrochloric acid to pH 2−3 by universal indicator, dilute with hot water up to 350−400 cm, heated to 50−70 °C, poured 1% alcoholic solution dimethylglyoxime an amount corresponding to 10 cmfor every 0.01 g of Nickel, and then pour the ammonia solution to pH 8−10 by universal indicator.

The solution with the precipitated sludge of dimethylglyoximato Nickel left at 50−70 °C for 1 h. the Precipitate was filtered off, the filter «white ribbon», washed 5−6 times with warm water.

After that, the precipitate is dissolved on the filter with 50 cmof hot hydrochloric acid, diluted 1:1. The filter was washed 5−7 times with hot water collecting the filtrate and washings in a beaker, in which was conducted the deposition. The solution is poured 5 cm50% strength solution of tartaric acid, a solution of ammonia to pH 8−10 by universal indicator hydrochloric acid to pH 2−3 by universal indicator and dilute with hot water up to 350−400 cm. The solution was then heated to 50−70 °C, poured 10−15 cm1% alcohol solution dimethylglyoxime, and then pour the ammonia solution to pH 8−10 by universal indicator. The solution with the precipitated sludge left at 50−70 °C for 1 h.

The precipitate is quantitatively transferred to a glass filtering crucible of No. 4, previously dried to constant weight at 110 °C and weighed. Precipitate was washed 7−8 times with warm water. The crucible with the precipitate is dried to constant weight at 110−120 °C, cooled in a desiccator and weighi

eshivot.

3.4. Processing of the results

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

,

where is the mass of sediment dimethylglyoximate of Nickel in the sample, g;

 — the mass of sediment dimethylglyoximate Nickel in a control experiment, g;

the weight of cast iron, g;

0,2032 — conversion factor dimethylglyoximate of Nickel on Nickel.

3.4.2. Allowable absolute discrepancies in the results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.

Table 2

3.3 to 3.4.2. (Changed edition, Rev. N 1).

4. ATOMIC ABSORPTION METHOD FOR THE DETERMINATION OF NICKEL

4.1. Atomic absorption method for the determination of Nickel GOST 12352−81.

Sec. 4. (Added, Rev. N 1).