GOST 13637.2-93

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  ГОСТ 13637.2-93

GOST 13637.2−93 Gallium. Atomic-emission method for the determination of cadmium, lead, zinc

GOST 13637.2−93

Group B59

INTERSTATE STANDARD

GALLIUM

Atomic-emission method for the determination of cadmium, lead, zinc

Gallium. Atomic-emission method for the determination of cadmium, lead, zinc

AXTU 1709

Date of introduction 1995−01−01

Preface

1. DEVELOPED by the Interstate technical Committee 104 «of the Semiconductor and rare metals products. Especially pure metals», State Institute of rare metals (Giredmet)

INTRODUCED by Gosstandart of Russia

2. ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 4−93 of 19 October 1993)

The adoption voted:

3. Resolution of the Committee of the Russian Federation for standardization, Metrology and certification from 02.06.94 N 160 inter-state standard GOST 13637.2−93 introduced directly as state standard of the Russian Federation from 01.01.95

4. REPLACE GOST 13637.2−77

INFORMATION DATA

REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard specifies a direct atomic emission method for the determination of mass fractions of impurities in Gaul:

The method is based on measuring the intensity of lines of impurity elements in the spectrum obtained during fractional evaporation of impurities from gallium laced with powdered graphite from a channel of a graphite anode in the arc DC.

Impurities in Gaul determined by calibration graphs constructed in the coordinates: logarithm of ratio of intensity of lines of the designated element to the background intensity (), the logarithm of the mass fraction of the element ().

1. GENERAL REQUIREMENTS

General requirements for methods of analysis and safety requirements according to GOST 13637.2.

2. APPARATUS, MATERIALS AND REAGENTS

The diffraction type spectrograph DFS-8 or similar type with the grating 600 gr/mm spectrograph medium dispersion type of ISP-28 or similar type with two-illumination system (condenser lens F-75, 25 mm in diameter).

The arc generator type DG-2 with optional rheostat or similar type adapted to ignite the DC arc high frequency discharge.

Rectifier 250−300, 30−50 A.

Microphotometer type MF-2 or similar type.

Spectromancer of PS-18 or similar type.

Laboratory scales of the 1st class according to GOST 24104*.
_______________
* On the territory of the Russian Federation GOST 24104−2001. — Note the manufacturer’s database.

Libra torsion bar type W to 500 mg or scales of the same type.

Mortar and pestle made of organic glass.

Box of organic glass.

Grinding machine graphite electrodes.

The shaped graphite electrodes for atomic-emission analysis of high purity-7−4, 6 mm in diameter, sharpened to a cone; or graphite electrodes, machined from high purity graphite rods-7−3, 6 mm in diameter, sharpened to a cone, with apex angle 15 degrees and with a platform with a diameter of 1.5 mm at the tip, burnt in the arc of direct current at 15 And during 15 s.

The shaped graphite electrodes for atomic-emission analysis of high purity-7−4, with a diameter of 6 mm, with a channel depth of 6 mm and a diameter of 4 mm; or graphite electrodes of the same size, machined from high purity graphite rods-7−3, burnt in the arc of direct current at 15 And during 15 s.

Cleaning firing is subjected to each pair of electrodes before measurement (electrode, sharpened to a cone — cathode, the electrode with the channel / anode).

Graphite powder of high purity according to GOST 23463.

Gallium metal, clean at the designated impurities, prepared as specified in GOST 13637.0.

Cadmium oxide according to GOST 11120.

Of lead oxide.

Zinc oxide according to GOST 10262.

Records of the photographic type SFC-04 and type SFC-02 size 9x12 cm or equivalent, providing normal blackening of analytical lines and the surrounding background in the spectrum.

The developer consisting of two solutions for photographic plates, type PFS-04.

Solution A:

Solution B:

Before applying the developer mix equal volumes of solutions A and B and add 5% by volume of ethyl alcohol. The time of development should be one and a half times more than the time specified on the package of photographic plates. The temperature of (20±1) °C.

Developer for photographic plates of type SFC-02 prepared according to GOST 13637.1.

Fixer:

Lamp infrared ikz-500 with voltage regulator type RNO 250−0,5, or controller of a similar type.

The technical rectified ethyl alcohol according to GOST 18300, nederevyannyy and double-distilled in quartz apparatus.

State standard samples (GSO) powder graphite SPG-27 PR GEO 2820−83, diluted powder of graphite is two-fold: in a mortar made of organic glass were placed 2 g GSO, add 2 g of powder graphite and carefully grind the mixture with ethanol for 50 min, and then dried under an infrared lamp.

3. PREPARATION FOR ASSAY

3.1. Sample preparation comparison (OS)

3.1.1. Each comparison sample is prepared immediately before the photographing of the spectrum, placing, as specified in clause 4.1, in the channel of the graphite electrode of 10 mg of the sample in comparison to graphite powder (OSGP) according to claim 3.2 and 100 mg of gallium, net-defined impurities. In terms of the method in accordance with the ratio of the masses of miscible substances, mass fraction of impurity in OS (calculated as mass fraction of admixtures in Gaul) is equal to one-tenth of the mass fraction of the impurities in OSGP.

3.2. Sample preparation comparison, graphite powder (OSGP)

Prepare the basic pattern of comparison for powdered graphite (OOGP) containing 1% cadmium, lead and zinc and 97% of carbon based on the content of the metal and carbon in mixtures of metals and carbon, mechanically mixing graphite powder with oxides of the respective metals. For this sample a mass 0,0114 g of cadmium oxide, 0,0108 g of lead oxide, 0,0124 g of zinc oxide and of 0.9700 g of powdered graphite is placed in a mortar made of organic glass and carefully grind the mixture with ethanol for 50 min, and then dried under an infrared lamp.

In order to avoid introducing dirt grinding in a mortar, and drying under a heat lamp are in the box of organic glass.

AOGP also allowed to cook by introducing the designated elements in the form of solutions (see GOST 13637.3).

ОСГП1-ОСГП8 prepare serial dilution OOGP, and then each subsequent sample is powdered graphite.

The mass fraction of each of the designated impurities in ОСГП1-ОСГП8 (based on mass fraction of metals in mixtures of metals and carbon), added to the mixture of sample powder of graphite and diluted sample, mixing for this sample are given in table.1.

Table 1

Are given in table.1 sample of powdered graphite and diluted sample was placed in a mortar made of organic glass, carefully triturated with ethyl alcohol for 30 min and dried under an infrared lamp. For ОСГП4-ОСГП8 drink alcohol, double distilled in quartz apparatus.

Grinding in a mortar, and drying under a heat lamp are in the box of organic glass.

When determining the zinc from 3·10to 1·10% use ОСГП1-ОСГП4. For other definitions used ОСГП4-ОСГП8. Mass fraction of impurities in the prepared from these samples comparison of OS (in percent, based on the mass percent of impurities in Gaul) are given in table.2.

Table 2

References on graphite powder store in tightly closed containers made of organic glass.

4. ANALYSIS

4.1. When recording the spectrum of the sample in the channel of the graphite electrode with a diameter of 4 mm and a depth of 6 mm is placed in series 10 mg of graphite powder and 100 mg of the sample of gallium pieces no larger than 3 mm in diameter (in order to avoid introducing contaminants to the sample of gallium is ground without removing the crystallized plate from a plastic bag).

When taking the spectrum of each reference sample into the channel of the graphite electrode with a diameter of 4 mm and a depth of 6 mm is placed in series 10 mg of the sample in comparison to graphite powder and 100 mg of gallium, determined by the net impurities, with pieces no larger than 3 mm in diameter.

The lower electrode with the sample of gallium (or reference) is an anode, the upper, sharpened to a cone — cathode. Between the electrodes ignite the arc DC power 15 A and the photographing range with exposure 40 s. During the exposure distance between the electrodes is maintained at 3 mm. Spectra in the region of wavelengths of 200−300 nm photographed with the spectrograph of the DFS-8 with a grating of 600 lines/mm operating in the first order, with an intermediate aperture 5 mm, or a spectrograph medium dispersion type of ISP-28, with an intermediate aperture of 5 mm. Width of slit of the spectrograph in both cases 15 microns. In a cassette load a record of type SFC-04 (in the determination of zinc from 3·10to 1·10% of the spectrum photographed on the photographic plates of type SFC-02).

The spectrum of each sample and the spectrum of each of the samples of the comparison register on the photographic plate three times. In addition, on the same plate thrice photographing range of the basics of samples of comparison; for this purpose, the channel of the graphite electrode with a diameter of 4 mm and 6 mm depth each time, place 10 mg of graphite powder and 100 mg of gallium, net-defined impurities.

Exposed photographic exhibit, washed with water, fixed, washed in running water for 15 min and dried.

5. PROCESSING OF THE RESULTS

5.1. In each spectrogram photometric blackening of analytical lines of the designated element (see table.3) and nearby background (minimum blackening near the analytical line of the element on either side, but with the same side in all the spectra taken on one disc) and calculate the difference pucherani .

Table 3

Three parallel values , , obtained three spectrograms taken for each sample, find the arithmetic mean of the results . According to the obtained average values are transferred to corresponding values of the logarithms of relative intensity using the table provided in Annex GOST 13637.1.

5.2. If the analytical line of the designated element in the spectra of samples basis of comparison is missing, using the values for the samples comparison (see table.2) and the obtained values , build a calibration curve in the coordinates . Mass fraction of impurities in the sample find the graph value for the sample.

5.3. Permissible discrepancies in the results of three parallel relations (the ratio of largest to smallest) and two results of the analysis (the ratio of largest to smallest) are shown in table.4.

Table 4

Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation.

5.4. If in the spectra of samples basis of comparison, there is a weak line of the element, then the construction of calibration curve in the coordinates , corrected for the mass fraction of the element in the sample comparisons. An amendment is permissible only under the condition that the mass fraction of the element in the sample comparison does not exceed the specified for the method lower limit of the interval defined by the mass fraction. If this condition is not met, it is necessary to choose for the basis of comparison samples a cleaner at the designated impurities of metallic gallium or graphite powder and phased perform a thorough cleaning of the premises, jobs, used equipment, reagents and materials

After receiving the adjusted calibration curve, calculate the mass fraction of impurities in Gaul, as specified in the claims.5.2, 5.3.

5.5. Control of the correctness of the analysis performed according to GOST 13637.0 or in the presence of state standard samples (GSO) powder graphite SPG-27 PR GEO 2820−83, as follows: in channels three graphite electrodes with a diameter of 4 mm and a depth of 6 mm injected with 100 mg of metallic gallium, pure at the designated impurities, and 10 mg diluted GEO.

Analysis of the mixture is carried out simultaneously with the analysis of samples for PP.4 and 5. For each impurity, calculate the ratio of the greater to the lesser of the two quantities as the result of the analysis of the obtained mixture diluted GSO and 0.5 certified value mass fraction of impurities in GSO. The results of the analysis of samples I think is right with confidence probability of 0.95, if the ratio is , where  — is regulated in paragraph 5.3, the permissible discrepancy of the two results of the analysis of the sample of gallium, with a mass fraction of impurities is equal to the result of analysis of a mixture of gallium with a dilute GEO.