GOST 24977.3-81
GOST 24977.3−81 Tellurium of high purity. Spectral method of determination of arsenic, antimony, mercury and cadmium (with Amendments No. 1, 2)
GOST 24977.3−81*
Group B59
STATE STANDARD OF THE USSR
TELLURIUM OF HIGH PURITY
Spectral method of determination of arsenic, antimony, mercury and cadmium
Tellurium high purity. Spectral method for the determination of arsenic, antimonic, mercury and cadmium
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
* REISSUE (March 1997) with Amendments No. 1, 2 approved in June 1987, September 1992 (IUS 11−87, 12−92)
This standard establishes a spectral method for the determination of arsenic, antimony, mercury and cadmium in tellurium of high purity in mass fraction of impurities in%:
arsenic 8·10-2·10
;
of antimony 2·10 — 1·10
;
mercury 2·10and 1.5·10
;
cadmium 1·10and 1.5·10
.
Determination of impurities in high purity tellurium is carried out by the method of «three standards» with the use of evaporation and excitation spectrum of the arc AC.
(Changed edition, Rev. N 1).
1. GENERAL REQUIREMENTS
1.1. General requirements — according to GOST and GOST 22306−77 24977.1−81.
2. APPARATUS, REAGENTS AND MATERIALS
2.1. Spectrograph with quartz optics medium variance type of ISP-30 spectrograph or with folded optics 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.
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.
Stainless steel tweezers medical GOST 21241−89.
Weights G-2−210 GOST 7328−82*.
______________
* On the territory of the Russian Federation GOST 7328−2001. — Note the manufacturer’s database.
The infrared lamp of any type with laboratory auto-transformer type CTL-250−2.
Cup quartz GOST 19908−90, with a capacity of 50 cm.
Mortar made of organic glass with a pestle.
Electrodes of coals brand-3M or-2M on the other 16−88, ILEA 757 with a diameter of 6 mm bore diameter (4,0±0,1) mm, channel depth (10±1) mm.
Contradictory from coals of brand-3M or-2M on the other 16−88, ILEA 757 with a diameter of 6 mm and a length of 30−50 mm.
Nitric acid GOST 4461−77.
Tartaric acid according to GOST 5817−77.
Photographic plates «spectrographic», type II or UFS.
Tellurium high purity brand T-B4 on the other 6−04−65−82 or brand «extra» on the other 48−0515−028−89.
Note. Allowed the use of devices with photoelectric registration of spectrum and other spectral instruments, reagents and other materials, dry plates, providing the accuracy rate, not inferior to current standards.
Elementary arsenic or arsenious anhydride.
Antimony GOST 1089−82.
Mercury oxide yellow according to GOST 5230−74.
Cadmium oxide according to GOST 11120−75.
The technical rectified ethyl alcohol GOST 18300−87.
(Changed edition, Rev. N 1, 2).
3. PREPARATION FOR ASSAY
3.1. References
Preparing two sets of samples compare. For the preparation of the first head of the reference sample containing 6% As The 1.5% Sb, 1.5% Hg weigh 9,088 g of metallic tellurium, 0,600 g of elemental arsenic, 0,150 g of antimony metal, 0,162 g of mercury oxide was placed in a mortar and thoroughly triturated for 1 h.
For the preparation of the second brain specimen for comparison containing 1.5% Cd, weighed and 0.172 g of the oxide of cadmium and 9,828 g of metallic tellurium was placed in a mortar and carefully fray for 60 min.
Dilution of pilot models comparison a hundred times (for two steps), and each newly acquired 2.5−3 times the tellurium get two set of working samples of the comparison containing the following mass fractions of impurities.
| The number of the reference sample (I set) | Mass fraction of impurities, % |
The number of sample comparison (set II) | Mass fraction, % | |
| arsenic |
antimony, mercury |
cadmium | ||
| 1 |
0,006 |
0,0015 |
1 |
0,0015 |
| 2 |
0,002 |
0,0005 |
2 |
0,0005 |
| 3 |
About 0.0006 |
0,00015 |
3 |
0,00015 |
| 4 |
0,0002 |
0,00005 |
4 |
0,00005 |
| 5 |
0,00008 |
0,00002 |
5 |
0,00002 |
Note. Depending on the composition of tellurium entering the analysis is allowed to change the mass percent of a particular impurity in the samples comparison.
Prepared samples of the comparison is stored in buksh or other container with tight-fitting lids.
The maximum allowable error value setting the values of CRM certified characteristics of the samples of the comparison does not exceed 0.03% of the certified value of the content component.
(Changed edition, Rev. N 1).
4. ANALYSIS
4.1. Samples and references Packed into the carbon electrodes (the full crater). From each sample prepared on eight sample comparison, four of the electrode.
Spectra photographed with the spectrograph on a photographic plate.
Evaporation of the sample and the excitation spectrum is carried out in the arc of an alternating current power 18 A, exposure — 60 s. one photographic plate is photographed at the four spectra of the sample and two comparison samples of the spectrum, burning at the two electrodes without moving the tape.
If the samples appeared line As 234,9 nm and As and Cd 228,8 nm, then write out As<0,00008%, Cd<0.00005% of the.
In the case that line As — 234,9 nm appeared, and the line Cd 228,8 nm visible, for the determination of cadmium prepared and photographed samples and the second set of samples comparison.
(Changed edition, Rev. N 1, 2).
5. PROCESSING OF THE RESULTS
5.1. With microphotometer measure the blackening of analytical lines () and background (
) near line (wavelengths in nm):
mercury Hgl 253,6;
antimony Sbl 259,8;
arsenic Asl 234,9;
cadmium Cdl 228.8 m.
On microphotometer measure the blackening of the lines of the designated element in the spectra of samples comparison in all three steps of the attenuator (see Annex 1 GOST 24977.1−81).
Build the characteristic curve of photographic plates and find the corresponding measured pochernenija the values of the logarithms of the intensity 
.
Calculate the value of a 
where
is the mass fraction of impurities in the reference sample, %. According to the obtained calibration chart find the content of impurities corresponding to the calculated sample values
For the results analysis be the arithmetic mean of results of two parallel measurements obtained on the same photographic plate, on the two spectrograms each.
(Changed edition, Rev. N 1,
2).
5.2. Discrepancies in the results of two parallel definitions and results of the two tests at p = 0.95 does not exceed the values given in the table.
| The designated element |
Mass fraction of element, % |
The discrepancy between the results of two parallel definitions % |
The discrepancy between the results of two tests, % |
| Arsenic |
8·10 |
2·10 |
4·10 |
1·10 |
0,3·10 |
0,5·10 | |
3·10 |
0,9·10 |
1,5·10 | |
1·10 |
0,3·10 |
0,5·10 | |
2·10 |
0,6·10 |
1·10 | |
| Antimony, mercury, cadmium |
2·10 |
0,8·10 |
1,4·10 |
1·10 |
0,4·10 |
0,7·10 | |
3·10 |
1·10 |
2·10 | |
1·10 |
0,4·10 |
0,7·10 | |
3·10 |
1·10 |
2·10 |
Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation or according to the formulas:
for arsenic:
for antimony, mercury and cadmium:
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).
