GOST 12226-80

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  ГОСТ 12226-80

GOST 12226−80 Platinum. Methods of analysis (modified N 1, 2, 3, 4, 5)

GOST 12226−80

Group B59

INTERSTATE STANDARD

PLATINUM

Methods of analysis

Platinum. Methods of analysis

AXTU 1709

Date of introduction 1981−07−01

INFORMATION DATA

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

DEVELOPERS

V. A. Korneev, V. E. Avramov, M. A. Gavrilov, G. N. Verkhoturov, A. K., Dementieva, I., Karshakevich

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 18.03.80 N 1201

Change No. 5 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 10 dated 04.10.96)

Was the Technical Secretariat of MGS N 2251

The adoption voted:

3. The frequency of inspection — 5 years

4. REPLACE GOST 12226−66

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

________________
* GOST 5962−67 not valid on the territory of the Russian Federation from 01.07.2001. Valid GOST R 51652−2000. «Rectified ethyl alcohol from food raw material. Technical conditions». Note the «CODE"

6. The expiration time limit is removed by the Resolution of Gosstandart from 24.02.92 N 174

7. REVISED (December 1998), with Changes N 1, 2, 3, 4, 5, approved in July 1985, March 1989, December 1990, February 1992, February 1997 (IUS 10−85, 6−89, 4−91, 6−92, 5−97).


This standard establishes spectrometry and spectrographic methods for determining the content of palladium, iridium, rhodium, ruthenium, gold, silver, iron, Nickel, copper, lead, silicon, zinc, aluminum, tin, antimony, magnesium and gravimetric method for the determination of volatile impurities.

The spectrometric method is based on spark excitation radiation between the sample of platinum and contradictator or translation of a sample of platinum in the globule, the evaporation of the elements in the arc of DC with subsequent photoelectric measurement of intensity of analytical lines of impurities.

Determine impurities: palladium, rhodium, iridium, ruthenium, lead — from 0.002 to 0.1 percent; magnesium, silicon, copper, aluminum, from 0.001 to 0.02% each; gold, Nickel, iron, zinc, silver, from 0.001 to 0.1% each; antimony — from 0.0005% to 0.02%; and tin from 0.0005 to 0.1%.

Spectrographic method is based on the translation of the shavings or powder of platinum in the globule, the evaporation of the elements of the impurities in the arc of DC and photographic registration of the spectra.

Determine impurities: palladium from 0.002 to 0.1%; iridium, rhodium, ruthenium is from 0.005 to 0.1% each; copper, Nickel, gold, magnesium, silver, from 0.001 to 0.01% each; aluminum, silicon, lead, zinc, from 0.001 to 0.02% each; iron is from 0.002 to 0.05%; tin and antimony from 0.0005 to 0.02% of each.

The gravimetric method is based on determining the loss on ignition by the mass difference of sample before and after calcination.

(Changed edition, Rev. N 2, 4, 5).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 22864.

(Changed edition, Rev. N 3).

1.2. (Deleted, Rev. N 3).

1.3. Mass fraction of impurities spectrographic and gravimetric methods determine at least four parallel batches; MS — at least four seats is one pill.

1.4,1.5. (Deleted, Rev. N 3).

2. SPECTROMETRIC METHOD

2.1. Apparatus, reagents and solutions

Quantometer emission ARL 31000 or other device of equal accuracy.

The generator of the unipolar low-voltage spark.

Press the str-60.

Steel mold with a matrix of an inner diameter of 40 mm.

A machine for sharpening metal bars.

Analytical scale.

Platinum rods with a diameter of 6 mm, length 150 mm (mass fraction of platinum 99,98%), sharpened on a cone at an angle of 90°.

The calibration samples.

Rectified ethyl alcohol according to GOST 5962.

Hydrochloric acid of high purity according to GOST 14261, diluted 1:1.

Distilled water.

Standard sample of platinum to verify the correctness of analysis results.

The spectral graphite electrodes net.

(Changed edition, Rev. N 3, 5).

2.2. Preparation for assay

For removal of surface contamination of platinum is boiled in hydrochloric acid for 2 min, washed with water and dried.

A sample of 30 g was placed in a mold and pressed into a tablet with a force of 540,000 N.

The tablet is placed on a stand water-cooled air tripod spectrometer. Contradictator is a platinum rod. Analytical gap 3±0.02 mm is installed by the template.

Tablet and a platinum rod electrodes are unipolar low-voltage spark.

If you come to the analysis of samples in the form of cast rods with a diameter of 6−8 mm, length 20−25 mm, the ends of the rods processed on a flat smooth surface, after which the platinum surface is cleaned as stated above.

The analysis in the arc of a DC sample of platinum weighing 150 mg were placed in the crater of the graphite electrode with a diameter of 6 mm (depth of crater, 1.5−2.0 mm, diameter 3.5−4.0 mm). Contradictator serve graphite rods with a length of 30−50 mm, sharpened to a truncated cone and a platform with a diameter of 2.5 mm.

2.3. Analysis

Sample of platinum serves as the anode (+) and contradicted — cathode (-).

Preparation of equipment for operation is carried out according to the instructions eksluatatsii devices.

Sample obygryvaet at least four times. After each sparking for a given analytical program automatically prints the results of the measurement for each item.

Contradicted replaced with a new one before burning a new sample.

2.2, 2.3 (Revised edition, Edit. N 5).

2.4. Processing of the results

The results of measurements using a DC line built for the calibration specimens, determine the mass percent of impurities.

When equipped with quantometer computer (PC) according to the given analytical program to automatically conduct the calculation the mass fraction and printing.

The final result of the analysis be the arithmetic mean of four measurements (obygryvanii), the maximum difference between them does not exceed the allowable discrepancy at a confidence probability P = 0,95.

If carried out calibration of measuring channels of the spectrometer for the calibration samples, the mass fraction of elements, impurities obtained by multiplying the registered value of the readings of the digital voltmeter to a scale which for each element is determined during calibration.

Analytical lines for analysis are presented in table.1.

Table 1

(Changed edition, Rev. N 3, 4).

2.4.1. The preparation of calibration samples (see section 3.4.3).

2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.3.

3. SPECTROGRAPHIC METHOD

3.1. Apparatus, reagents and solutions

A diffraction spectrograph with a grating of 600 lines/mm.

Three-step attenuator with transmittance levels of 100, 40 and 10%.

Generator DC arc power up to 15 A.

Geregistreerde microphotometer.

Steel mold with a matrix of an inner diameter of 4 mm.

Grinding machine graphite electrodes.

The spectral graphite electrodes-pure grades of high purity 7−3, high purity 7−4, b-3, with a diameter of 6 mm.

The calibration samples.

Photographic plates of the spectral type of ES sensitivity of 5−10 units GOST 10691.1 or type 2 sensitivity 16 units

Rectified ethyl alcohol according to GOST 5962.

Hydrochloric acid of high purity according to GOST 14261, diluted 1:1.

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

Standard sample of platinum to verify the correctness of analysis results.

(Changed edition, Rev. N 3).

3.2. Preparation for assay

For removal of surface contamination of platinum is boiled in hydrochloric acid for 2 min, washed with water and dried.

Sample weighing 150 mg was placed in a cratered graphite electrode (crater depth of 1.5−2.0 mm, diameter 4 mm). In the case of the analysis of the spongy platinum sample metal pressed with a force of 500−1000 N.

Contradictator serve graphite rods with a length of 30−50 mm, sharpened on pecheny cone (with a platform 2.5 mm diameter).

3.3. Analysis

The spectra of the calibration samples are photographed and analyzed on the spectrograph: the slit width of 0.015 mm, the light slit being a capacitor, the current of 10−12 A, exposition 60 s. the test sample is the anode. Analytical gap 2.5 mm adjust in the process of exhibiting spectra in the image on the intermediate diaphragm. From each sample of the calibration samples and specimens receive one spectrum.

Photographic plates showing for 5 min at developer temperature of 20 °C. Shown photographic plates rinsed in water, fixed, washed in running water, dried and photometric.

3.4. Processing of the results

3.4.1. For all elements of the internal standard serve line platinum. Determination of mass fraction of impurities is carried out by the method of «three standards».

Analytical lines for analysis are presented in table.2.

Table 2

3.4.2. Using microphotometry measure the amount of blackening of analytical lines and the internal standard.

Using the characteristic curve, which is constructed for each spectrogram, determine the logarithm of the ratio of the intensity of analytical lines of impurities and the internal standard.
The calibration graphs are built in coordinates , x — axis is the (logarithm of the mass fraction of the calibration samples); on the y-axis(the logarithm of the ratio of the intensity of the impurity line to the line of the internal standard).

In the region of high mass fraction allowed the construction of calibration graphs in the coordinate , where is the difference of pochernenija analytical lines and the internal standard.

For the calibration chart to find the mass fraction of impurities in the analyzed samples.

The final result of the analysis be the arithmetic mean of four parallel measurements, the maximum difference between them does not exceed the permissible discrepancy at a confidence probability P = 0,95.

3.4.3. The preparation of calibration samples

Calibration samples for spectral analysis were prepared by direct introduction of the calculated quantity of powders of impurities (grade hç) in the spectral pure platinum (mass fraction of platinum is not less than 99,98%).

Sample impurities with a small amount of platinum pressed into a tablet (to avoid loss of impurities), then the pill and the rest of platinum is placed in a graphite crucible and melted in a heating furnace of the type IST-016 at 1950 °C for 20 min.

After melting the ingots are purified from mechanical inclusions, washed in hydrochloric acid and rasstraivaet chips of size 1 mm. Chips boil in hydrochloric acid, washed with distilled water and dried.

The purity of platinum up to determine the melting spectrographic method under the same conditions under which to conduct analysis. Impurities that are found in platinum, is determined by a method of additives, and found the mass fraction take into account when producing the calibration samples.

Prepare a series of six calibration samples in the range of mass fraction of from 0.0005 to 0.1%. Allowed the preparation of calibration samples by another method ensuring the specified accuracy of the analysis.

3.4.4. The difference between the results of parallel measurements and the results of the analysis shall not exceed the values of permissible differences given in table.3.

Table 3

3.4.1−3.4.4. (Changed edition, Rev. N 3).

4. GRAVIMETRIC METHOD FOR THE DETERMINATION OF LOSS ON IGNITION

4.1. Equipment

Furnace for calcination at 800−900 °C.

Platinum crucibles N 100−4 according to GOST 6563.

Crucibles porcelain low N 3 according to GOST 9147.

Analytical scale.

Desiccator, according to GOST 25336.

(Changed edition, Rev. N 2).

4.2. Analysis

Clean platinum crucible with a constant specific mass is placed in a porcelain crucible and calcined in a furnace for 10−15 minutes at a temperature of 650−800 °C. after calcination porcelain crucible with platinum are removed from the oven, cooled in a desiccator to a temperature of (20±5) °C and determine the mass of the platinum crucible.

After that it is weighed 5.0 g of the analyzed metal. The crucible with metal and placed in a porcelain crucible and calcined in a furnace under the same conditions for 20−25 min, remove the porcelain crucible with the platinum crucible from the furnace and cooled in a desiccator to a temperature of (20±5) °C.

A platinum crucible is weighed, placed in a porcelain crucible and calcined under the same conditions for 10−15 min, then cooled in a desiccator and re-weighed. The operation of calcination and cooling, the crucible is repeated until obtaining constant weight of the platinum crucible with metal.

The difference between the mass of the crucible with the metal before and after incineration gives the mass loss during annealing in the sample.

(Changed edition, Rev. N 1, 2, 4).

4.3. Processing of the results

Mass fraction loss during annealing (a) percentage calculated by the formula

where the difference in mass of the crucible with the metal before calcination and after calcination, g;

 — weight of metal,

For the results analysis be the arithmetic mean of four parallel measurements, the maximum difference between them does not exceed 0,005% at a mass fraction loss during annealing up to 0.02% and 0.01% when the mass fraction of loss on ignition of from 0.02 to 0.05% at confidence probability P = 0,95.

(Changed edition, Rev. N 4).