GOST 18904.0-89
GOST 18904.0−89 Tantalum and its oxide. General requirements for methods of analysis
GOST 18904.0−89
Group B59
STATE STANDARD OF THE USSR
TANTALUM AND ITS OXIDE
General requirements for methods of analysis
Tantalum and its oxide. General requirements for methods of analysis
AXTU 1709
Valid from 01.01.90
to 01.01.95*
___________________________________
* Expiration removed
Protocol N 4−93 inter-state Council
for standardization, Metrology and certification
(IUS N 4, 1994). — Note the manufacturer’s database.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
PERFORMERS
L. N. Filimonov, N. Arakelyan, A. S. Terekhov
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. INSTEAD 18904.0 GOST-73
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Item number |
| GOST 8.315−78 | 1.12 |
| GOST 12.0.004−79 | 2.4 |
| GOST 12.1.004−85 | 2.2 |
| GOST 12.4.021−75 | 2.3 |
| GOST 1770−74 | 1.1 |
| GOST 6709−72 | 1.7 |
| GOST 9147−80 | 1.1 |
| GOST 13718−68 | 1.2 |
| GOST 14919−83 | 1.5 |
| GOST 19908−80 | 1.1 |
| GOST 20292−74 | 1.1 |
| GOST 25336−82 | 1.1 |
This standard establishes General requirements for methods of analysis of tantalum and its oxide.
1. GENERAL REQUIREMENTS
1.1. For analysis using volumetric glassware below the second accuracy class according to GOST 20292* and GOST 1770, and glassware according to GOST 25336, crockery and equipment according to GOST 9147, dishes made of transparent quartz GOST 19908**, dishes made of glassy carbon brand SU-2000.
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* On the territory of the Russian Federation there are 29169−91 GOST, GOST 29227−91−29229−91 GOST, GOST 29251−91-GOST 29253−91;
** On the territory of the Russian Federation GOST 19908−90. — Note the manufacturer’s database.
1.2. For weighing, use an analytical laboratory scales VLR-20G, torsion scales W 500 GOST 13718, technical scales of the type VPT-1 Libra or similar types.
1.3. Sample analyze samples and materials used for sample preparation and comparison of standard solutions weighed on an analytical balance (weighing results in grams is recorded with precision to the fourth decimal place).
Sample of analyzed samples comparison in the course of spectral analysis is weighed on the analytical or torsion balance (the weighing results in grams is recorded with accuracy to the third decimal place).
Attachment of reagents to prepare the developer and fixer, and floodplains are weighed on a technical scale (weighing in grams is recorded with precision to the first decimal place).
1.4. For calcining and fusing used laboratory muffle furnace MP-2УМ, PM-8, or equivalent, providing heating temperature up to 1000 °C.
1.5. For heating use electric cooker with a sealed coil according to GOST 14919.
1.6. The purity of the metals used for the preparation of standard solutions and comparison samples shall be not less than 99.5%.
1.7. For the preparation of solutions and tests used distilled water according to GOST 6709, deionized water and reagents qualification not lower than h.d. a.
1.8. Developer and fixer are prepared in accordance with the recipe attached to the photographic plates.
1.9. Allowed the use of other equipment, materials, utensils and reagents, subject to obtaining the metrological characteristics are not inferior to the specified in the standard methods of analysis.
1.10. The numerical value of the result of the analysis must end with the same number of discharges, and the corresponding value of acceptable divergence.
1.11. In standard methods of analysis given the allowable differences for several values of the mass fraction of the element. Allowable differences for intermediate values of the mass fraction of the element is calculated using linear interpolation.
1.12. The accuracy of analysis results control using standard samples of the composition. The result of the analysis obtained from parallel measurements, is considered correct if the absolute value of the difference of the analysis result and the certified value at confidence probability of 0.95 does not exceed
where is the accuracy evaluation of the standard sample;
2;
3;
— the permissible discrepancy between the results of the analysis.
Use of industry standard reference materials and standard samples of enterprises certified in accordance with GOST 8.315.
In the absence of standard samples used in the methods of control listed below.
1.13. The accuracy of the analysis by the photometric method control method supplements. The Supplement should two to three times greater than the value of the mass fraction of the designated impurities in the sample. If the value of the mass fraction determined by impurities does not exceed the lower limit of detectable concentrations, the additive is 2−3 times higher than the value of lower limit of detectable concentrations.
The results of the analysis are considered correct if the absolute value of the difference () the calculated (mass fraction determined by impurities with the additive) and the values at confidence probability
of 0.95 satisfies the ratio
where 0.7 for
2,
of 0.6 to
3;
is the number of parallel definitions;
and
is of acceptable divergence, respectively, for the mass fraction determined by the impurity and the mass fraction determined by impurities with the additive, is given in the standard method of analysis.
The value of the mass fraction determined by impurities with the additive should not exceed the upper limit of detectable concentrations
.
1.14. The accuracy of the analysis results by the spectral method is controlled for each of the designated impurities in the transition to a new set of samples comparison.
For this purpose the same samples containing the designated impurity, using the old and new sets of samples comparison get four results analysis and calculate the arithmetic mean of these results. The results are considered correct if the difference of the average values of the old and new sets of samples of the comparison is less than half the discrepancy for the mass fraction, equal to the average value of the results of the analysis of the old set of samples comparison.
Monitoring is carried out for each interval between samples comparisons on a rolling analysis of appropriate samples.
Quality control set of samples of the comparison may be performed using a set of standard samples of oxide tantalum (set SOT-17) 2798−83 GSO N — GSO N 2803−83.
1.15. It is allowed to control the precision of analysis results by comparison with results obtained by another method. The absolute value of the difference () of the analysis results obtained by the two methods at confidence probability
of 0.95 should satisfy the following relation
where — the permissible discrepancy of the two results of the analysis obtained by the first method;
— the permissible discrepancy of the two results of the analysis obtained by the second method.
1.16. In the expression «diluted 1:1, 1:2, etc.» the first digits stand for the volumetric part of concentrated acid, the second volume of the water.
1.17. Before preparing samples for spectral analysis of oxide and salt is calcined or dried to constant weight at the following temperatures (degrees Celsius);
oxide: vanadium (V) — 500−600, tungsten (VI) — 650, iron (III) — 700−800, cobalt (II, III) — 800, silicon (IV) — 700−800, copper (II) — 600, molybdenum (VI) — 450−550, niobium (V) — 800, tin (IV) — 600−700, titanium (IV) — 700−800, zirconium (IV) — 700−800; sodium chloride — 100−120.
1.18. Allowed to dilute the oxidized sample at 5−10 times the tantalum pentoxide clean at the designated impurities in the spectral analysis of the samples with a mass fraction of impurities above the upper limit specified in the standards.
2. SAFETY REQUIREMENTS
2.1. Tantalum and its compounds in air of working zone do not form toxic substances and belong to the fourth class of danger.
2.2. Laboratory spaces where chemicals are treated in batches of tantalum, should be equipped with ventilation systems according to GOST
2.3. Fire safety laboratory spaces shall be provided in accordance with the requirements of GOST 12.1.004*.
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* On the territory of the Russian Federation GOST 12.1.004−91. — Note the manufacturer’s database.
2.4. To work in the analytical laboratory should be allowed persons who have been duly instructed in accordance with GOST 12.0.004*.
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* On the territory of the Russian Federation GOST 12.0.004−90. — Note the manufacturer’s database.
2.5. General safety requirements in the analysis of the tantalum — according to normative-technical documentation.
