GOST 9853.16-96

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  ГОСТ 9853.16-96

GOST 9853.16−96 Titan spongy. Method for the determination of tungsten

GOST 9853.16−96

Group B59

INTERSTATE STANDARD

TITANIUM SPONGE

Method for the determination of tungsten

Sponge titanium. Method for determination of tungsten

ISS 77.120
AXTU 1709

Date of introduction 2000−07−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 105, Ukrainian research and design Institute of titanium

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 19 October 1999 No. 353-St inter-state standard GOST 9853.16−96 introduced directly as state standard of the Russian Federation from July 1, 2000.

4 INTRODUCED FOR THE FIRST TIME

1 Scope

This standard sets the photometric method for the determination of tungsten (at a mass fraction of Volfram from 0.005% to 0.5%) in the spongy titanium according to GOST 17746.

The method is based on the formation in the hydrochloric acid medium is colored yellow-green complex compound of tungsten (V) thiocyanate ammonium with subsequent measurement of optical density of the solution.

2 Normative references

The present standard features references to the following standards:

GOST 8.315−97 State system for ensuring the uniformity of measurements. The standard samples. The main provisions, the order of development, certification, approval, registration and application

GOST 4204−77 sulfuric Acid. Specifications

GOST 4328−77 Sodium hydroxide. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 14261−77 hydrochloric Acid of high purity. Specifications

GOST 17746−96 spongy Titanium. Specifications

GOST 18289−78 Sodium volframovich 2 water. Specifications

GOST 23780−96 spongy Titanium. Methods of sampling and sample preparation

GOST 25086−87 non-ferrous metals and their alloys. General requirements for methods of analysis

GOST 27067−86 Ammonium radamisty. Specifications

3 General requirements

3.1 General requirements for the method of analysis according to GOST 25086.

3.2 Selection and preparation of samples is carried out according to GOST 23780.

3.3 Mass fraction of tungsten is determined in two batches.

4 measuring instruments and auxiliary devices

The spectrophotometer or photoelectric colorimeter concentration of type KLF-2, or similar device.

Hydrochloric acid according to GOST 14261, of 1.19 g/cmand diluted 1:1, 2:1.

Sulfuric acid according to GOST 4204, diluted 1:1 and 1:4.

Nitric acid according to GOST 4461.

Sodium hydroxide according to GOST 4328, solutions of the mass concentrations of 20 and 200 g/DM.

Ammonium thiocyanate (ammonium radamisty) according to GOST 27067, solution mass concentration of 500 g/DM.

Titanium trichloride (titanium (III) chloride) according to the current normative document, solution mass concentration 10 g/DM. A solution of titanium chloride mass concentration 10 g/DMis prepared as follows: 1 g of shavings of titanium grade TG-120 is placed in a conical flask with a capacity of 250 cm, flow 50 cmhydrochloric acid solution (2:1), cover with a watch glass or funnel glass and lead dissolution by heating, maintaining a constant volume by the addition of hydrochloric acid. The solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 100 cm, is poured a solution of hydrochloric acid (2:1) to the mark and mix.

Titanium sponge grade TG-120 according to GOST 17746.

Sodium tungstate (sodium wolframates) 2-water according to GOST 18289.

Filter «white ribbon» according to the current normative document.

Standard samples according to GOST 8.315.

Standard solutions of tungsten.

Solution a: 1,7941 g of sodium tungstate are placed in a conical flask with a capacity of 250 cm, pour 100 cmof sodium hydroxide solution mass concentration of 20 g/DMand dissolved under moderate heating. The solution was cooled to room temperature, transferred to a measuring flask with volume capacity of 1000 cm, is poured a solution of sodium hydroxide mass concentration of 20 g/DMup to the mark and mix.

1 cmof the solution contains 0.001 g of tungsten.

Solution B: 5 cmsolution And placed in a volumetric flask with a capacity of 100 cm, is poured a solution of sodium hydroxide mass concentration of 20 g/DMup to the mark and mix.

1 cmof a solution of 0.00005 g contains tungsten.

5 procedures for measuring

5.1 the sample the sample weight of 0.5−2.0 g was placed in a conical flask with a capacity of 250 cm, 70 cm pour thehydrochloric acid solution (1:1), beaker cover watch glass or funnel glass and lead the dissolution of the sample when heated in a constant volume by the addition of hydrochloric acid. After complete dissolution of the sample in the solution was added dropwise nitric acid until the disappearance of violet colour, poured 20 cmof sulfuric acid solution (1:1), evaporated to the appearance of sulphuric acid fumes and heating was continued for 3 min.

The solution was cooled to room temperature, poured 40 cmof water and heated to dissolve the salts, and then neutralized with sodium hydroxide solution the mass concentration of 200 g/DMbefore the first blooming. To the solution (to remove the resulting turbidity) add a few drops of sulfuric acid (1:4) and the solution was carefully transferred into a measuring flask with a capacity of 200 cmcontaining 30 cmof boiling sodium hydroxide solution mass concentration of 200 g/DM(in which case the precipitation of the hydroxides of iron, Nickel, titanium, zirconium, chromium, niobium). Solution and the precipitate is cooled, made up to the mark with water and mix. After 20−25 min, the solution was filtered through a dry filter medium density «white ribbon».

Aliquot part of the solution 5−20 cmis placed in a dry volumetric flask with a capacity of 50 cm, flow 20 cmof hydrochloric acid (of 1.19 g/cm).

The solution was cooled, poured 3 cmof a solution of ammonium thiocyanate, and added dropwise in about 15 drops (5 drops servings) solution of titanium trichloride steady yellow-green in color. Topped up to the mark with hydrochloric acid (1:1) and stirred.

After 15 min measure the optical density of the solution at a wavelength of 440 nm thick absorbing layer of 50 mm. Solution comparison the solution serves as the reference experiment. Mass fraction of tungsten in the sample is calculated according to the calibration

graphics.

5.2 For constructing the calibration curve in six of the seven volumetric flasks with a capacity of 50 cmplaced 0,1; 0,5; 1,0; 1,5; 2,0; 2,5 cmstandard solution B, which corresponds to 0,000005; 0,000025; 0,000050; 0,000075; 0,000100; 0,000125 g of tungsten. A seventh solution of the flask is a solution of the reference experiment.

All flasks are poured 1 cmof sodium hydroxide solution mass concentration of 200 g/DM, 20 cmof hydrochloric acid (of 1.19 g/cm). The solution is cooled, add 3 cmof a solution of ammonium thiocyanate and then do as described in 5.1.

According to the obtained values of optical density and corresponding mass of tungsten to build a calibration curve.

6 Processing of measurement results

Mass fraction of tungsten , %, is calculated by the formula

, (1)

where is the mass of tungsten in the sample solution, g;

 — total volume of sample solution, cm;

 — the mass of sample, g;

 — volume aliquote parts of a solution of the sample, cm.

7 the Permissible error of measurement

7.1 the discrepancy between the measurement results and analysis results (at a confidence probability of 0.95) shall not exceed the permissible values given in table 1.


Table 1

Percentage

7.2 accuracy Control of the results of the analysis carried out according to standard sample in accordance with GOST 25086.

Allowed to monitor the accuracy of analysis results by the method of additives in accordance with GOST 25086.

Additives is a standard solution A.

8 qualifications

To perform analysis allowed the analyst qualification not less than 4th level.