GOST 20996.9-82

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  ГОСТ 20996.9-82

GOST 20996.9−82 Selenium technical. Method for the determination of antimony (with Amendments No. 1, 2)

GOST 20996.9−82*

Group B59

INTERSTATE STANDARD

SELENIUM TECHNICAL

Method for the determination of antimony

Selenium. Method of antimony determination

AXTU 1709

Date of introduction 1983−07−01

Resolution of the USSR State Committee on standards of 22 June 1982, N 2481 date of introduction is established 01.07.83

Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

* PUBLISHING (may 2000) with amendment No. 1, approved in December 1987 (IUS 3−88)


The Change N 2, approved and promulgated by the Order of Rosstandart on 09.04.2015 N 250-St c 01.09.2015

Change No. 2 made by the manufacturer of the database in the text ICS N 7, 2015


This standard specifies the extraction-photometric method for the determination of antimony (in mass fraction of antimony 0,005−0,06%).

The method is based on reaction of formation of colored complex compounds of the anion (SbCl)with crystal violet, 1.5−2 n hydrochloric acid solution, extracted with toluene, and subsequent measurement of optical density at a wavelength of 608−610 nm.

(Changed edition, Rev. N 1).

1A. NORMATIVE REFERENCES

This standard uses the regulatory references to the following international standards:

GOST 1089−82 Antimony. Specifications

GOST 1770−74 (1042−83 ISO, ISO 4788−80) Glassware volumetric laboratory glass. Cylinders, beakers, flasks, test tubes. General specifications

GOST 3118−77 Reagents. Hydrochloric acid. Specifications

GOST 4147−74 Reagents. Iron (III) chloride 6-water. Specifications

GOST 4197−74 Reagents. Sodium nitrous acid. Specifications

GOST 4204−77 Reagents. Sulphuric acid. Specifications

GOST 4461−77 Reagents. Nitric acid. Specifications

GOST 5789−78 Reagents. Toluene. Specifications

GOST 6691−77 Reagents. Urea. Specifications

GOST 6709−72 distilled Water. Specifications

GOST 20996.0−82 Selenium technical. General requirements for methods of analysis

GOST 24104−2001* laboratory Scales. General technical requirements
________________
* On the territory of the Russian Federation GOST R 53228−2008 «Scales non-automatic actions. Part 1. Metrological and technical requirements. Test».


GOST 25336−82 Glassware and equipment laboratory glass. The types, basic parameters and dimensions

GOST ISO 5725−6-2002* Accuracy (trueness and precision) of methods and measurement results. Part 6. The use of precision values in practice
________________
* On the territory of the Russian Federation GOST R ISO 5725−6-2002 «Accuracy (trueness and precision) of methods and measurement results. Part 6. The use of precision values in practice».


Note — When using this standard appropriate to test the effect of reference standards in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet or published annually by the information sign «National standards» published as on January 1 of the current year and related information published monthly indexes published in the current year. If the reference standard is replaced (changed), when using this standard should be guided by replacing (amended) standard. If the reference standard is cancelled without replacement, then the situation in which the given link applies to the extent that does not affect this link.


(Added, Rev. N 2).

1B. CHARACTERISTICS OF INDICATORS OF MEASUREMENT ACCURACY

The accuracy of measuring the mass fraction of antimony corresponds to the characteristics given in table 1 (with R=0,95).

Limit values of repeatability and reproducibility of measurements for a confidence probability P=0.95 is given in table 1.


Table 1 — values of the indicator of measurement accuracy, limits of repeatability and reproducibility of measurements of mass fraction of antimony

Percentage

Section 1B. (Added, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 20996.0−82.

2. MEASUREMENT MEANS, AUXILIARY DEVICES, MATERIALS, SOLUTIONS

When performing measurements using the following measuring instruments and auxiliary devices:

— spectrophotometer or photoelectrocolorimeter with all accessories necessary for measurements at a wavelength of 608−610 nm;

— scale special accuracy class according to GOST 24104;

— the stove is electric with a closed heating element for temperature up to 350 °C;

— volumetric flasks 2−25−2, 2−50−2, 2−100−2, 2−1000−2 according GOST 1770;

— glasses-1−100 TCS-1−250 TCS according to GOST 25336;

glass hour;

— separating funnel VD-1−250 TC GOST 25336.

When taking measurements, use the following products and solutions:

— nitric acid according to GOST 4461;

— hydrochloric acid according to GOST 3118, diluted 1:10 and 3:1;

— sulfuric acid according to GOST 4204, diluted 1:1, 1:10;

— tin dichloride 2-water [1], the solution of the mass concentration of 200 g/lin hydrochloric acid, diluted 3:1;

sodium nitrous acid according to GOST 4197;

— urea according to GOST 6691;

— crystal violet [2], solution of the mass concentration of 2 g/DM;

— toluene according to GOST 5789;

— iron chloride according to GOST 4147, solution mass concentration of 100 g/lin hydrochloric acid, diluted 3:1;

— distilled water according to GOST 6709;

— antimony GOST 1089.

(Changed edition, Rev. N 1, 2).

3A. PREPARATIONS FOR THE MEASUREMENTS

3A.1. In the preparation of a saturated solution of urea 100 g of urea dissolved in 100 cmof hot water.

3A.2. To construct the calibration curve, prepare solutions of known concentration of antimony.

In preparing the solution And the mass concentration of antimony 0.1 mg/cma portion of the antimony with a mass of 0.1 g was placed in a beaker with a capacity of 250 cm, flow 20 to 25 cmof sulphuric acid diluted 1:1, cover the watch glass and heated to dissolve sample. Remove the glass, the solution was cooled and transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with sulfuric acid diluted 1:10, and stirred.

In the preparation of a solution of mass concentration of antimony 0.01 mg/cmtaken 10 cmof solution A and placed in a volumetric flask with a capacity of 100 cm, top up with water to the mark with hydrochloric acid, diluted 3:1, and stirred.

When cooking solution To the mass concentration of antimony 0.001 mg/cm,taken 10 cmof a solution and transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with hydrochloric acid, diluted 3:1, and stirred.

3A.3. Construction of calibration curve

Six glasses with a capacity of 100 cmeach placed 0; 2,0; 5,0; 7,0 cmsolution and 1.0; 2.0 cmof solution B, which corresponds to 0; 0,002; 0,005; 0,007; 0,01 and 0,02 mg of antimony, pour 1 cm()of a solution of ferric chloride, made up with hydrochloric acid diluted 3:1 to volume of 10 cm, and then perform in accordance with 3.1.

Section 3A. (Added, Rev. N 2).

3. ANALYSIS

3.1. A portion of selenium with a mass of 0.5−2.0 g were placed in a glass with a capacity of 150−200 cm, 15−25 cm pour thenitric acid and the solution is evaporated to a volume of 3−5 cm. Add 5−10 cmof sulphuric acid (1:1) and evaporated to sulphuric acid fumes. Cool, wash with water the walls of the beaker and evaporated again to 3−5 cm. After cooling, pour the 20−25 cmof a hydrochloric acid solution (3:1), dissolve the salt in low heat and transfer the solution into volumetric flask with a capacity of 50 or 100 cm, is poured a solution of hydrochloric acid (3:1) to the mark and mix.

Aliquot part of the solution of 5 or 10 cm(or the entire solution, depending on the mass fraction of antimony) was transferred to a beaker with a capacity of 100−250 cm, are added dropwise a solution of tin chloride to a bleaching solution. If the solution is colorless, add only 1−2 drops.

Then pour 1 cmazotistykh sodium and allow solution to stand for 2 min. then add 1 cmof urea and the resulting solution was transferred in a separating funnel with a capacity of 200 cm, 10−12 cm was addedhydrochloric acid (1:1) and topped the volume with water to 75−80 cm.

In the separating funnel is poured 20−25 cmof toluene, 1 cmcrystal violet and extracted 1 minute After separation the organic layer is separated, transferred to a volumetric flask with a capacity of 25 cm, made up the volume to the mark with toluene and after 15 min measure the optical density of colored solution on a photoelectrocolorimeter, using a filter with maximum transmittance at a wavelength of 608−610 nm and cuvette thickness of the absorbing layer of 10 mm Solution comparison is the solution of the reference experiment. Mass of antimony find graduirovannam

mu schedule.

(Changed edition, Rev. N 1).

3.2. (Changed edition, Rev. N 1); (Deleted, Rev. N 2).

4. PROCESSING OF THE RESULTS

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

,

where the amount of antimony found in the calibration graphics mg;

 — volume of the volumetric flask, cm;

 — volume aliquote part of the solution, cm;

 — weight of selenium,

4.2. The measurement results take the arithmetic mean of two parallel definitions, provided that the absolute difference between them in terms of repeatability does not exceed the value (at confidence probability P=0,95) repeatability limit rgiven in table 1.

If the difference between the highest and lowest results of parallel measurements exceeds the limit value of the frequency of occurrence, perform the procedure described in GOST ISO 5725−6 (paragraph 5.2.2.1)

(Changed edition, Rev. N 2).

4.3. The absolute value allowable discrepancies between the two measurement results obtained in different laboratories, should not exceed the limit values for the reproducibility given in table 1 (at confidence probability P=0,95). At default of this condition can be used the procedure set out in GOST ISO 5725−6.

(Added, Rev. N 2).

Bibliography

________________
* THAT are not given. For additional information, please refer to the link. — Note the manufacturer’s database.


(Added, Rev. N 2).