GOST 9853.1-96

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  ГОСТ 9853.1-96

GOST 9853.1−96 Titan spongy. Method for determination of nitrogen

GOST 9853.1−96

Group B59

INTERSTATE STANDARD

TITANIUM SPONGE

Method for determination of nitrogen

Sponge titanium.
Method for determination of nitrogen

ISS 77.120*
AXTU 1709
____________________
* In the index «National standards» in 2007.
ISS 77.120 and 77.120.50. — Note the manufacturer’s database.

Date of introduction 2000−07−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 105; Ukrainian scientific-research and design titanium Institute

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 9853.1−96 introduced directly as state standard of the Russian Federation from July 1, 2000.

4 REPLACE GOST 9853.1−79

5 REISSUE. July 2005

1 Scope

This standard specifies a volumetric method for the determination of nitrogen in spongy titanium (with mass fraction of nitrogen from 0.005% to 0.5%) according to GOST 17746.

The method is based on the dissolution of titanium in sulfuric and fluoride-hydrogen acids, resulting in solution formed ammonium salt. The latter is decomposed with sodium hydroxide with evolution of ammonia, which absorb acidic indicator solution Tashiro and titrated with sulfuric acid 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 3118−77 hydrochloric Acid. Specifications

GOST 3640−94 Zinc. Specifications

GOST 4165−78 Copper (II) sulfate 5-water. Specifications

GOST 4204−77 sulfuric Acid. Specifications

GOST 4328−77 Sodium hydroxide. Specifications

GOST 10484−78 hydrofluoric Acid. Specifications

GOST 17746−96 spongy Titanium. Specifications

GOST 18300−87 ethyl rectified technical. 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
________________
* On the territory of the Russian Federation the document is not valid. Standards 25086−2011, here and hereafter. — Note the manufacturer’s database.

3 General requirements

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

3.2 Sampling and sample preparation is carried out according to GOST 23780.

3.3 the result of the analysis taking the arithmetic mean of the results of the two measurements. In the beginning of the shift hold at least two control experiments.

4 measuring instruments and auxiliary devices

The device for determination of nitrogen content (figure 1) consists of: washing of bottles 1, filled with sulphuric acid (1:1), crater 2, with hydraulic shutter, fridge 3 (figure 2), flask of the Kjeldahl type 4 with a capacity of 250 cm, mantle 5, microburette 6 with a capacity of 5 cm, vessel for absorption and titration of the ammonia 7 (figure 3), drain cock 8.

Figure 1

Figure 2

Figure 3

The conical flask with a capacity of 250 cmwith stopper (figure 4), which serves for the decomposition of the sample.

Figure 4

Tank with flat water.

Electric heating device with a weak heating of the closed type.

Compressed air or highway with a compressed air pressure of 0.01 to 0.02 MPa, flow rate of about 3 DM/min.

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

Sulphuric acid. Standard-titer (fixanal) according to the current normative document, solutions of molar concentration and 0,005 0,0025 mol/DM. Mass concentration of these solutions of sulfuric acid is set at the standard sample of titanium, similar in chemical composition and nitrogen content to the sample of titanium and carried out through all stages of the analysis. The mass concentration of sulfuric acid solution , g/cmof nitrogen, calculated by the formula

, (1)

where  — mass fraction of nitrogen in the standard sample, %;

 — weight of standard sample, g;

 — the volume of sulfuric acid solution consumed for titration of the standard sample, cm;

 — the volume of sulfuric acid consumed for titration in the reference experiment, cm.

1cmof sulphuric acid molar concentration of 0.0025 mol/DMcorresponds to 0,00007 g of nitrogen molar concentration 0,0050 mol/DM — 0,00014 g of nitrogen.

Acid fluoride-hydrogen GOST 10484, diluted 1:5.

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

Potassium chlorate (potassium rate) according to the current normative document, pre-calcined at a temperature of 723−773 K.

Copper sulfate (copper sulphate) according to GOST 4165.

Zinc metal granulated GOST 3640.

Sodium hydroxide according to GOST 4328, solution mass concentration of 400 g/DM: 1200 g of sodium hydroxide was placed in a flask with a capacity of 3.0 DM, add 9−10 granules of zinc metal and 10 to 15 g of sulphate of copper, pour a 2.0 DMwater, stirred and boiled for 40 min in low heat, then cooled, made up to 3.0 DMwater and filter the solution through glass wool. The resulting solution was stored in tightly closed polyethylene containers, the shelf life is 6−7 days.

Methyl red according to the current normative document.

Methylene blue according to the current normative document.

Ethanol (ethyl alcohol) rectified technical GOST 18300.

Indicator Tashiro: 0.06 g of methyl red and 0.04 g methylene blue dissolved in 100 cmof ethanol.

Flat water: 10 cmTashiro indicator, dilute with water to 2.0 DMstore in tightly sealed dark glass containers. Flat water has a purple-red color in acid medium and green in alkaline.

Standard samples according to GOST 8.315.

5 preparation for measurement

5.1 sample Preparation

The analyzed sample before starting work clear of pollution. This titanium chips were washed with ethanol at the rate of 10 cmper 1 g of shavings and dried.

5.2 preparing the installation

The glass part of the unit is treated with superheated steam in the reaction flask pour 200cmof water into the vessel to absorb the ammonia and the titration flow 20−30 cmflat water supply compressed air, and heat the reaction flask on the hot plate-mantle to a boil.

Preparation of flat water to the work produced by the addition of sulfuric acid solution of molar concentration of 0.0025 mol/luntil the color changes from green to violet-red.

If the neutralization of 100 cmof distillate consumed 0.8−1.2 cmof sulfuric acid solution of molar concentration of 0.0025 mol/DM, consider ready to work.

Stop heating and compressed air, water is removed from the reaction flask and the indicator the water from the vessel to absorb the ammonia.

6 procedures for measuring

A portion of the sample weighing 1 g (in mass fraction of nitrogen from 0.005% to 0.1% inclusive) or 0.5 g (at a mass fraction of nitrogen is from 0.1% to 0.5% inclusive) is placed in a conical flask with a capacity of 250 cm, 30 cm, pouredsulphuric acid (1:4) or 30 cmof hydrochloric acid (1:1) and 5 cmfluoride-hydrogen acid (1:5) and close the flask with the stopper (figure 4).

The sample is first dissolved at room temperature, and then with moderate heating to complete dissolution. If the bottom of the flask with dark particles of non-dissolving the residue, which may contain nitrides and carbonitrides, the solution is evaporated until the appearance of sulphuric acid fumes. Then the solution was cooled, added with 1 g of potassium chlorate and repeat the evaporation to dense white fumes selection.

The flask with the solution was then cooled, the stopper is washed with water and attach it to the solution.

In the sink pour the 20−30 cmflat water, compressed air is applied to the system and water in the fridge.

In the reaction flask through a funnel pour 50 cmof sodium hydroxide solution and the solution, then wash the flask and the walls of the funnel in small portions of water and turn up the heat.

As the distillation of ammonia and absorption of its water lead indicator titration with sulfuric acid solution of molar concentration of 0.0025 mol/DMto restore the original weak purple-red color of the indicator water. To avoid peretiranie, acid is added dropwise. If the indicator water remains weak purple-red color within 3−5 minutes, the distillation is done.

The volume of the sulfuric acid molar concentration of 0.0025 mol/DMconsumed for titration, calculate the content of nitrogen in the sample.

A control experiment is conducted through all stages of the analysis. With an unstable value in the reference experiment, repeat it during a shift 1−2 times. The average value of the result of the reference experiment must not exceed the permissible differences given in table 1.


Table 1

Percentage

When the mass fraction of nitrogen from 0.2% to 0.5% inclusive allowed to be used as the titrant in the analysis and control experience of the sulfuric acid molar concentration of 0.005 mol/DM.

The determination of nitrogen should be carried out in premises which are not working with ammonia and other nitrogen compounds.

7 Processing measurement results

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

, (2)

where is the volume of sulfuric acid solution consumed for titration of the sample, cm;

 — the volume of sulfuric acid consumed for titration in the reference experiment, cm;

 — mass concentration of sulfuric acid solution used for titration of the sample, in terms of nitrogen, g/cm;

 — the weight of the portion of the sample,

8 Allowable measurement uncertainty

8.1 the discrepancy between the measurement results and analysis results (at a confidence probability =0,95) shall not exceed the permissible values given in table 1.

8.2 Control of accuracy of analysis results carried out on standard samples of any category that are similar in chemical composition to the analyzed material in accordance with GOST 25086.

9 qualifications

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