GOST 24977.1-81

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  ГОСТ 24977.1-81

GOST 24977.1−81 Tellurium of high purity. Chemical-spectral method of determination of impurities (with Amendments No. 1, 2)

GOST 24977.1−81*

Group B59

STATE STANDARD OF THE USSR

TELLURIUM OF HIGH PURITY

Chemical-spectral method of determination of impurities

Tellurium high purity. Method of chemical and spectral for the determination of impurities

AXTU 1709

Date of introduction 1983−01−01

Resolution of the USSR State Committee on standards dated September 30, 1981 N 4486 time of the introduction set with 01.01.83

Resolution of the state standard from 07.09.92 N 1123 removed the limitation of the validity period

REPLACE GOST 17434−72

* REISSUE (March 1997) with Amendments No. 1, 2 approved in June 1987, September 1992 (IUS 11−87, 12−92)


This standard specifies the chemical-spectral method of determination of indium, gallium, chromium, lead, manganese, silver, and copper in high purity tellurium brand T-B4 when the mass fraction of impurities in%:

The method is based on the separation of the main mass of tellurium in the dioxide and spectrographic analysis of the resulting concentrate of impurities. The enrichment coefficient is in the range from 20 to 25.

Spectral analysis of the concentrate is carried out by the method of «three standards» with the use of the evaporation of impurities and the excitation spectrum of the arc AC.

1. GENERAL REQUIREMENTS

1.1. General requirements — according to GOST 22306−77 with the following addition listed below.

1.2. A sample of tellurium in pre-wear in a mortar made of organic glass to fine powder, passing through sieve 0,071 mm according to GOST 6613−86. For analysis take two sample of tellurium weighing 5 g.

1.3. Discrepancies in the results of parallel measurements () and the results of two tests () must not exceed the established standards of permissible differences.

Numeric values of analysis results are rounded in expressing a number with the last digit the same category as the values of the corresponding allowable differences.

1.4. Control of correctness of the analysis carried out according to GOST 22306−77 each time at replacement of a batch of samples comparison, in the repair of installations, after long interruptions and other changes that affect the result of the analysis.

1.3, 1.4. (Changed edition, Rev. N 2).

1.5. For the manifestation of the photographic plates used metalhydrogen developer consisting of two solutions which, before manifestation of the mixed 1:2.

Note. Allowed to apply contrast-the developer of another composition.


The acidic fixer of the following composition:

1.6. Safety requirements

1.6.1. All installations of the laboratory of spectral analysis must be placed at a distance of not less than 1.5 m from one another. Electric devices and installations used in the tests shall conform to the electrical codes, GOST 12.2.007.0−75.

Samples of tellurium in plastic packaging and reagents used for the analysis in the original packaging, should be kept in a special Cabinet or box, equipped with ventilation.

(Changed edition, Rev. N 1, 2).

1.6.2. In the use and operation of electrical appliances and electrical installations in the process of spectral analysis required to comply with the rules of technical operation of electrical consumers* and safety rules at operation of electrical installations** approved by the state energy supervision and GOST 12.3.019−80.
________________
* On the territory of the Russian Federation there are «Rules of technical operation of electrical installations», approved by order of Ministry of energy of Russia from 13.01.2003 No. 6;
** In the territory of the Russian Federation act «Interbranch rules on labor protection (safety rules) for electrical installations» (SWEAT P M-016−2001, RD 153−34.0−03.150−00). Here and further. — Note the manufacturer’s database.

In the analysis of tellurium, the following reagents and materials which have a deleterious effect on the human body: lead, chromium, copper, indium, manganese, antimony, mercury, ammonia, nitric acid, carbon electrodes, when sharpening which is formed of carbonaceous dust.

When performing tests, it is necessary to observe the basic rules of safe work in chemical laboratories*.
________________
* On the territory of the Russian Federation the document is not valid. Acts PND f 12.13.1−03. — Note the manufacturer’s database.


(Changed edition, Rev. N 1).

1.6.3. Each excitation source must be placed inside of the device, equipped with local suction device to remove from the air ozone, nitrogen oxides, metallic oxides and carbon monoxide emitted in the sources of spectra excitation and bad acting on the working body, a protective screen to prevent burn by ultraviolet rays.

1.6.3.1. The machine is used for grinding carbon electrodes must have a built-in exhaust air inlet to prevent the ingress of carbon dust in the air, in quantities exceeding maximum permissible concentration.

(Changed edition, Rev. N 1).

1.6.3.2. Preparation of samples for analysis (the taking of test portions, grinding, mixing with carbon powder) should be carried out in fume cupboards or boxes, equipped with ventilation device.

1.6.4. The analysis of tellurium in the air of working zones are formed harmful substances listed in the table.1.

Table 1

Control of content of harmful substances in the air of working zone should be carried out in accordance with GOST 12.1.007−76 and GOST 12.1.005−88.

Analysis of air samples for harmful substances is carried out according to the technical conditions for methods of determination of harmful substances in the air, approved by the Ministry of health of the USSR.

1.6.5. All the remains of the metal tellurium, which are not used for analysis shall be returned to the manufacturer (customer).

If necessary, recycling, disposal and destruction of hazardous wastes from the production tests carried out in accordance with the documentation approved in the established order and agreed with the sanitary-epidemiological service of the Ministry of health of the USSR.

1.6.6. The laboratory of spectral analysis must have General ventilation and local exhaust ventilation in accordance with the requirements of GOST 12.4.021−75.

To prevent entering the working area of harmful substances emitted in the sources of spectra excitation and bad acting on the body working, and also for protection from electromagnetic radiation and prevent sunburn by ultraviolet rays, each a source of excitation spectra should be placed inside of the device, equipped with an integrated exhaust air inlet, in accordance with the requirements of GOST 12.4.021−75 and the protective screen according to GOST 12.1.019−79.

1.6.6.1. All work in the test must be performed in a dry working clothes and safety devices in accordance with typical industry norms of free issue of workwear, footwear and protective equipment to workers and employees.

Clothing should be stored in a special tightly sealed closets, separate from your own clothes, weekly, handing it to the Laundry. The removal of clothing and stay outside of the working space, is prohibited.

1.6.6.2. Working in the chemical and spectral laboratories are provided with milk in accordance with the rules of free issue of milk or other equivalent food products to workers and employees in factories, workshops, sections and other subdivisions with harmful working conditions, which must be taken before or after work.

1.6.6−1.6.6.2. (Changed edition, Rev. N 1).

1.6.6.3. After finishing work with tellurium you need to thoroughly wash hands, don gloves, then remove the gloves and again wash hands with soap and brush.

1.6.7. To work in the chemical and spectral laboratories are open to persons under the age of 18, trained in the basic techniques of working on appliances and electrical installations in accordance with the rules of safety at operation of electroinstallations of consumers, approved by Gosenergonadzor USSR, and methods of analysis. Coming to work and working should be held: preliminary and periodic medical examinations in accordance with the instructions of the Ministry of health of the USSR. Preliminary training in the work with hazardous substances and the rules for the treatment of protective equipment; special safety instructions with the corresponding record in the prescribed manner in accordance with GOST 12.0.004−90.

(Changed edition, Rev. N 1).

2. APPARATUS, MATERIALS, REAGENTS

The diffraction type spectrograph DFS-8 (grating 600 gr./mm, first order) or type STE-1 with a being system of the slit illumination and the three-step attenuator.

Microphotometer designed to measure the density of blackening of spectral lines.

Spectromancer of PS-18.

The generator is activated the arc AC of any type.

Grinding machine carbon electrodes.

Laboratory scales General purpose of the 2nd accuracy class with a weighing error of no more than 0.0002 g according to GOST 24104−88*.
______________
* On the territory of the Russian Federation GOST 24104−2001. — Note the manufacturer’s database.

Libra torsion bar type W with a weighing error of no more than 0.001 g according to GOST 13718−68.

Weights G-2−210 GOST 7328−82*, tweezers medical stainless steel according to GOST 21241−89.
______________
* On the territory of the Russian Federation GOST 7328−2001. — Note the manufacturer’s database.

Boxes of organic glass.

Infrared lamp with laboratory auto-transformer type CTL-250−2 or similar.

Hot plate with thermostat.

Quartz tableware (glasses, cups) according to GOST 19908−90.

Cup vypaivali of PTFE with a capacity of 100−200 cm.

The quartz distillation apparatus for the distillation of reagents.

Mortar made of organic glass with a pestle.

Electrodes from coals of high purity on the other 48−20−78−75, with a diameter of 6 mm, the size of the crater 3,8x4 mm.

Contradictory from coals of high purity on the other 48−20−78−75, with a diameter of 6 mm, a length of 30−50 mm, one end sharpened to a hemisphere or a truncated cone with the diameter of the pad is 1.5−2 mm.

Nitric acid of high purity according to GOST 11125−84, if necessary, distilled twice in a quartz apparatus, and solutions of 1:1 and 1:4.

The graphite powder of high purity according to GOST 23463−79.

Tellurium high purity brand T-B4 on the other 6−04−65−82 or «extra» on the other 48−0515−028−89.

The technical rectified ethyl alcohol GOST 18300−87.

Ammonium chronologicly according to GOST 3774−76.

Plate photographic SFC-02, the SFC-03, size 130х180 mm on THAT 6−43−1475−88.

Note. Allowed the use of devices with photovoltaic spectra and other spectral instruments, reagents and other materials, dry plates, providing the accuracy rate, not inferior to the regulated current standards.


Indium GOST 10297−94.

Gallium GOST 12797−77.

Lead according to GOST 3778−77*.
______________
* On the territory of the Russian Federation GOST 3778−98. — Note the manufacturer’s database.

Manganese GOST 6008−90.

Copper GOST 859−78*.
______________
* On the territory of the Russian Federation GOST 859−2001. — Note the manufacturer’s database.

Silver GOST 6836−80*.
______________
* On the territory of the Russian Federation GOST 6836−2002. — Note the manufacturer’s database.

Mass fraction of metal not less than 99.99%.

Solutions of pure metals.

A solution of gallium: 0.5 g of metal was dissolved in 10 cmof nitric acid solution 1:1, and the solution heated to boiling to remove the oxides of nitrogen, cooled, quantitatively transferred to a volumetric flask with a capacity of 100 cm, add 5 cmof nitric acid was adjusted to the mark with water and mix.

1 cmof the solution contains 0.005 g of gallium.

Solution India: 0.5 g of metal was dissolved in 10 cmof nitric acid solution 1:1, and the solution heated to boiling, cooled, quantitatively transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

1 cmof the solution contains 0.005 g India.

The solution of lead: 0.5 g of metal was dissolved in nitric acid solution 1:4, and the solution heated to boiling, cooled, transferred quantitatively into a measuring flask with a capacity of 100 cm, adjusted to the mark with nitric acid solution 1:1 and stirred.

1 cmof the solution contains 0.005 g of lead.

A solution of chromium: 1,4615 g chromological ammonium is dissolved in 50 cmof water, transferred quantitatively into a measuring flask with a capacity of 100 cm, adjusted to the mark with water and mix; the solution is used in the preparation day.

1 cmof the solution contains 0.005 g of chromium.

The solution of manganese: 0.05 g of the metal is dissolved in 10 cmof nitric acid solution 1:1, and the solution heated to boiling, cooled, transferred quantitatively into a measuring flask with a capacity of 100 cm, adjusted to the mark with water and mix.

1 cmof the solution contains 0.0005 g of manganese.

The copper solution: 0.05 g of the metal is dissolved in 10 cmof nitric acid solution 1:1, is quantitatively transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

1 cmof the solution contains 0.0005 g of copper.

Silver solution: 0.05 g of silver dissolved in 10 cmof nitric acid solution 1:3 with a weak heating, the solution was cooled and quantitatively transferred to a volumetric flask with a capacity of 100 cm, add 5 cmof nitric acid was adjusted to the mark with water and mix.

1 cmof the solution contains 0.0005 g of silver.

For the preparation of solutions it is possible to use the oxides, carbonate, or nitrate salts of the above metals qualification h. d. a. or H. h

(Changed edition, Rev. N 1, 2).

3. PREPARATION FOR ASSAY

3.1. Tellurium dioxide. In a quartz glass with a capacity of 200 cm100 cm pournitric acid 1:1, heated on a hotplate up to 40−50 °C and in small portions (500 mg) was added a suspension of tellurium with a mass of 15 g. Dissolution of particles of tellurium in each portion must be complete. The reaction should proceed continuously, for this, the solution is slightly heated on a small hotplate.

The resulting solution together with the precipitate is evaporated under the lamp to obtain a wet salt (the remaining volume of acid should be not less than 3−5 cm).

To the residue add 150 cmof hot water, with drops of tellurium dioxide. The glass is cooled in running water and the cooled solution was decanted. The precipitate is washed twice with 30 cmof water, then dried under lamp to remove the smell of nitric acid. Dried and thoroughly mixed tellurium dioxide stored in a plastic jar.

Samples comparison. For preparation of the main reference sample containing 0.1% of indium, thallium, chromium, lead, and 0.01% of manganese, silver, copper, in a quartz Cup was placed 5.0 g of graphite powder and nakatyvaet 1 cmof the solution. With the introduction of the solutions ensure that the solution impregnating base does not impinge on the sides and bottom of the Cup. To do this, as the fluids of impurities of the graphite powder is dried under a lamp until the disappearance of the smell of nitric acid.

The resulting mixture was thoroughly stirred in a mortar for 60 min after mixing the graphite powder of the basic sample compare to five times, every five or two times to prepare a series of working samples comparison, which is mixed with pure tellurium dioxide of 4:1.

References, mixed with tellurium dioxide, contain amounts of impurities indicated in the table.2.

Table 2

Prepared samples of the comparison is stored in a plastic container with a tight-fitting lid.

(Changed edition, Rev. N 2).

4. ANALYSIS

A sample of tellurium in pre-wear to fine powder in a mortar made of organic glass.

For analysis take two sample of tellurium by weight at 5.0 g.

In quartz beakers with a capacity of 100 cmis placed 30 cmof nitric acid solution 1:1, heated to 40−50 °C and poured into them a sample of tellurium separate portions (each serving approximately 500 mg). Each portion is added after complete dissolution of the particles of the elemental tellurium from the previous portions. The reaction should proceed continuously, for which the solution is slightly heated on a hotplate laboraratory.

Each of the resulting solutions together with precipitated precipitate is evaporated under the lamp to obtain a wet salt, then pour 50 cmof hot water. Slow evaporation of solution acidity should be about 19 g/lfor methyl violet (yellow-green color). The solutions and the precipitate was boiled for 3 min, then cooled in tap water for 60 min. Cooled the solutions were decanted into pre-weighed cups of PTFE. Precipitation is washed twice by decantation with 10 cmof water. Rinse water is attached to all solutions and evaporated to dryness.

Cups of dry residues weighed, determine the mass of concentrate and compute the enrichment coefficient () by the formula

,

where is the mass of test portion, g;

 — mass of the concentrate,

To carry out control experience in a Cup made of PTFE with a capacity of 100 cmare placed 200 mg of tellurium dioxide, poured 30 cmof nitric acid, evaporated to small volume, poured 70 cmof water and evaporated to dryness. All operations is carried out simultaneously with the preparation of the concentrates. For each batch of samples prepared at the same time, conducted two test experience.

Each of the concentrate and the concentrate control experience mixed with graphite powder 4:1. Prepared from the concentrates of the samples and control experiments and comparison of samples taken on a torsion balance sample weighing 40 mg and put them in the craters, carbon electrodes, reducing the size of the coating a kick ball made of organic glass.

The enrichment coefficient () in the reference experiment is calculated by the formula

,

where  — weight of tellurium taken for analysis, g;

 — weight of tellurium dioxide, taken as the basis for analysis,

The electrodes are pre-fired in an arc alternating current power of 10 A for 15 s. From each of the concentrate and the reference sample prepared via the two electrodes.

Spectra of comparison samples and samples photographed with a diffraction spectrograph on a photographic plate using a three-step attenuator and a width of slit of the spectrograph 0.025 mm in the Interelectrode gap of 2.5 mm.

Evaporation of the sample and the excitation spectra are produced in the arc of an alternating current power 12 A. Exposure of 40 s. On the same photographic plate at the two pictures of the spectrum of each reference sample concentrate of the sample and the reference experiment.

(Changed edition, Rev. N 1, 2).

5. PROCESSING OF THE RESULTS

5.1. With microphotometer measure of the blackening of the lines defined by the elements () and the minimum darkening of the background () around each of these lines (wavelengths in nm):

indium Inl 303,94;

gallium Gal 294,36;

chromium Cr II 283,56;

lead PbI 283,31;

manganese Mnl 279,83;

copper Cul 327,40;

silver Agl 328,07.

On microphotometer measure the density of blackening of the line of the designated element in the spectra of the calibration samples in all three steps of the attenuator (see annexes 1−2), build a response curve and find the appropriate measured values , the values of and . Calculate the value , find the average value for the two spectra of each reference sample, concentrate the sample and control experience. Calibration graphs constructed in the coordinates , and find them in the content of impurities in the concentrates of samples and control experiments.

Mass fraction of element (a) in percent is calculated by the formula

,

where  — mass fraction of the element in the concentrate of the sample, %;

 — mass fraction of the element in a control experiment, %;

the enrichment coefficient;

the enrichment coefficient in the reference experiment.

For the results analysis be the arithmetic mean of results of two parallel measurements on the two spectrograms each received on the same photographic plate.

(Changed edition, Rev. N 1, 2).

5.2. Discrepancies in the results of two parallel measurements () and the results of two tests () at a confidence probability of 0.95 should not exceed the values given in table.3.

Table 3

Permitted discrepancies for the intermediate mass fraction of impurities calculated using linear interpolation or formulas to India, copper, chromium and lead:

; in the range of a mass fraction of from 5·10to 1·10%;

;  — in the range of mass fraction from 1·10to 1·10%;

for manganese:

;  — in the range of mass fraction from 1·10to 1·10%;

for silver:

;  — in the range of mass fraction from 1·10to 1·10%,

;  — in the range of a mass fraction of from 3·10to 1·10%,

;  — in the range of mass fraction from 1·10to 1·10%;

for thallium:

;  — in the range of a mass fraction of from 3·10to 1·10%,

;  — in the range of mass fraction from 1·10to 1·10%,

where is the arithmetic mean of the results of parallel measurements;

 — the average of the two results of the analysis.

(Changed edition, Rev. N 2).

ANNEX 1 (reference). THE CONSTRUCTION OF THE CHARACTERISTIC CURVE OF PHOTOGRAPHIC PLATES WITH SPECTRA OF SAMPLES OF THE COMPARISON TAKEN THROUGH A THREE-STAGE ATTENUATOR

ANNEX 1
Reference

The photometer measures the blackening of the lines of the designated element in the spectra of samples comparison in all three steps of the attenuator. Denote these conditional steps like 100, 50 and 10%. Calculate the difference of pochernenija lines 100 and 50% steps . For those spectra in which two steps of attenuation are in the region of normal pochernenija, this difference is constant, equal to where the factor of contrast of the photographic plates, the difference in transmittance of the steps of the attenuator (passport).

The coordinate axis is applied to the graph paper, plotting the y-axis blackening in the scale of 1 mm =0.01 units, starting from =0.

Calculate the average of five or six difference values of pucherani between 100 and 50% steps for the region of normal pucherani .

Point 1 are arbitrarily chosen abscissa and ordinate equal to the blackening of the beginning of the straight portion of the characteristic curve (approx 0.50 for plates of type ES). From point 1 to the right count the number of millimeters equal to the difference between transmittance of 100% and 50%-tion steps of the attenuator — (for passport reliever) multiplied by 100 and put a point 2.

From the received point 2 lay up the number of millimeters equal to the average value of the difference of pochernenija multiplied by 100 and put a point 3.

The resulting point 3 connect a straight line from point 1 and continue straight until =1,80. This video corresponds to the region of normal pucherani characteristic curve.

In cases where the blackening of the lines in the 100% step is too large, instead of the difference between 100 and 50% steps building is carried out by difference between 50 and 10% steps.

To build the field of neoteric use spectra, in which one of the steps is in the normal range, and the second in neoteric.

Find of the spectrum at the straight portion of the characteristic curve point, the ordinate of which is equal to the blackening line at 100% (or 50%) step. From this point to the left count the number of millimeters equal to the difference between the transmittance of the attenuator steps, multiplied by 100, and the abscissa to find the point with ordinate equal to the blackening of the same line in a more relaxed step.

So come with all measured pochernenija. Connect the resulting points with a smooth curve since the beginning of the straight section.

On the x-axis is applied to the values in the scale of 1 mm =0.01 units, starting from an arbitrarily chosen origin.

(Changed edition, Rev. N 2).

ANNEX 2 (informative). AN EXPLANATION OF THE CALCULATION OF THE RESULTS OF THE ANALYSIS WITH SPREADSHEETS ACCOUNTING BACKGROUND

ANNEX 2
Reference

In the characteristic curve of photographic plates to find the measured pucherani lines together with the background and background the corresponding values of and .

Subtracting from the value of the corresponding value of the find . In the table, for each values placed in the first column, find the corresponding second column value .

The magnitude of the corresponding calculated values

The end