GOST 12224.1-78

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  ГОСТ 12224.1-78

GOST 12224.1−78 Osmium. Chemical-spectral method of analysis (with Amendments No. 1, 2, 3)

GOST 12224.1−78

Group B59

INTERSTATE STANDARD

OSMIUM

Chemical-spectral method of analysis

Osmimum. Chemical-spectral method of analysis

AXTU 1709

Date of introduction 1980−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

DEVELOPERS

A. K., Dementieva, I., Karshakevich

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on standards 04.07.78 N 1794

Change No. 3 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 10 dated 04.10.96)

Was the Technical Secretariat of MGS N 2249

The adoption voted:

3. REPLACE GOST 12224−66 in part of sec. 2

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 4−93 of the Interstate Council for standardization, Metrology and certification (ICS 4−94)

6. REPRINT (January 1999) with Amendments No. 1, 2, 3, approved in June 1984, may 1989, February 1997 (IUS 10−84, 8−89, 5−97)


This standard specifies the chemical-spectral method of determination of platinum, iridium, iron, Nickel, ruthenium (when the mass fraction of from 0.001 to 0.02% of each), palladium, rhodium, gold, silver, copper, silicon, barium, sodium, aluminum (with a mass fraction of from 0.0005 to 0.02% of each), magnesium (with a mass fraction of from 0.0001 to 0.004%) in osmium.

The method is based on the Stripping of osmium in the tetroxide and the evaporation residue, mixed with graphite powder from the crater of the graphite electrode arc AC.

(Changed edition, Rev. N 3).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 22864.

(Changed edition, Rev. N 1).

2. APPARATUS, REAGENTS AND SOLUTIONS

Tubular electric furnace at 1000 °C.

The vacuum pump.

The quartz spectrograph medium dispersion (like ISP-30).

Trehlistnyj glass spectrograph (ISP-51 with a camera 270 mm).

Spectrograph with crossed dispersion, STE-1 (can be used instead of the first two for simultaneous detection of ultraviolet and visible region of the spectrum).

The generator is activated the arc AC.

Microphotometer geregistreerde.

Flask Bunsen.

Pumps platinum according to GOST 6563.

Pumps porcelain N 3 according to GOST 9147.

Analytical scale.

Agate mortar with pestle.

Spatula made of organic glass and a paint brush to extract residue from the boat after the distillation of osmium.

Buxy, desiccators for storage of samples and calibration samples; cell and tweezers for the treatment of photographic films or photographic plates.

Powder high purity graphite brand.

The spectral graphite electrodes-pure grades p-3, p-2, with a diameter of 6 mm.

Samples of the calibration.

Rectified ethyl alcohol technical GOST 18300 to wipe the sealed jars, weights and equipment.

Phototechnical film «Mikrat-200» and film positive MZ-35 on the other 6−17−647 or photographic plates of the spectral type of ES the relative sensitivity of 5−10 units, and «pangram».

Sodium hydroxide according to GOST 4328, a solution of 2.5 mol/DM.

The flask Drexel with a capacity of 500 cm.

Developer and fixer according to GOST 10691.0, GOST 10691.1. Allowed to use other contrast working developer.

Standard sample composition of osmium to verify the correctness of analysis results.

Section 2. (Changed edition, Rev. N 1, 2).

3. PREPARATION FOR ASSAY

3.1. Metal weight 3.0 g was placed in a platinum boat, inserted in a porcelain boat and placed in a tubular electric furnace. One end quartz tube electric furnace remains open, and the other is hermetically connected with a Bunsen flask, the flask Drexel and vacuum line.

In a flask Bunsen poured 500 ml, and the flask Drexel 250 cmof sodium hydroxide solution, turn on the furnace and the system connected to vacuum lines. The furnace is gradually heated to 600 °C and held at this temperature for 1.5−2 h. Then a solution of sodium osmate from the flask Bunsen decanted into another flask, and the flask Bunsen poured fresh solution of sodium hydroxide and heating was continued. If within 30 minutes of the alkaline solution is not colored, oxidation and Stripping of osmium considered complete. The boat is removed from the furnace and cooled.

(Changed edition, Rev. N 1, 2).

3.2. The platinum boat with the rest placed 50 mg of graphite powder. The balance together with graphite powder carefully extracted from a platinum boat in an agate mortar, add graphite powder to 300 mg, triturated for 30 min and placed press-fit into the crater of the graphite electrode (diameter 3.5−4.0 mm, depth 2−2,5 mm). The counter serve as graphite rods with a length of 30−50 mm, sharpened to a truncated cone.

3.3. Calibration samples for the spectral analysis are prepared by mixing powders of impurities (qualifications hç particle size of 0.15 mm), with graphite powder. First, prepare the basic pattern from which you select a few samples to check the homogeneity of the distribution of impurities. The sample diluted with graphite powder to obtain a series of six samples in the range of a mass fraction of from 0.0001 to 0.2%.

Allowed the preparation of calibration samples in a different way.

3.2, 3.3. (Changed edition, Rev. N 2).

4. ANALYSIS

4.1. Spectra of the calibration samples, the standard sample and samples photographed on the coupled spectrographs under the following conditions: the width of the slit of the quartz spectrograph of 0.015 mm, the width of the slit of a glass spectrograph 0.005 mm; illumination slit being a condenser, an arc gap of 2.5 mm, the current strength of 6.5−7 A, exposition 60 s.

The ultraviolet portion of the spectrum photographed on the quartz spectrograph to a positive film type MZ-35 or a photographic plate of the type ES.

The visible portion of the spectrum photographed on the glass spectrograph on phototechnical film «Mikrat-200» or a photographic plate of the type «pangram». Photographic film (photographic plates) are within 5 min at a developer temperature of 20 °C. Shown photographic plates and films rinsed in water, fixed, washed in running water, dried and photometric.

(Changed edition, Rev. N 1, 2, 3).

5. PROCESSING OF THE RESULTS

5.1. When fotomaterialy lines of impurities take into account the background. The intensity of the background subtracted from the intensity of the analytical lines of impurities with the help of characteristic curve. Mass fraction of impurities determined by the method of «three standards».

The wavelengths of the analytical lines given in table.1.

Table 1

The calibration graphs are built in coordinates , the abscissa shows the delay (the logarithm of the mass fraction of the calibration samples), y-axis (the logarithm of the ratio of the intensity of impurity lines to the background). For the calibration chart to find the mass fraction of impurities in the analyzed samples.

(Changed edition, Rev. N 2, 3).

5.2. Mass fraction of impurities () in percent is calculated by the formula

,

where  — mass fraction of the element in graphite powder, %;

 — mass analyze of graphite powder mg;

 — weight of sample, mg.

5.3. Permissible discrepancies in the results of parallel definitions should not exceed the values given in table.2.

Table 2

5.2, 5.3. (Changed edition, Rev. N 2).