GOST 23862.0-79

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  ГОСТ 23862.0-79

GOST 23862.0−79 Rare-earth metals and their oxides. General requirements for methods of analysis (with Amendments No. 1, 2)

GOST 23862.0−79

Group B59

INTERSTATE STANDARD

RARE EARTH METALS AND THEIR OXIDES

General requirements for methods of analysis

Rare-earth metals and their oxides. General requirements for methods of analysis

ISS 77.120.99
AXTU 1709

Date of introduction 1981−01−01

The decision of the State Committee USSR on standards on October 19, 1979 N 3988 date of introduction is established 01.01.81

Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

EDITION with Amendments No. 1, 2 approved in April 1985, may 1990 (IUS 7−85, 8−90).

1. This standard establishes General requirements for methods of analysis of rare earth metals and their oxides.

2. Sampling is carried out according to normative-technical documentation for products of this type.

3. For the preparation of solutions and tests used distilled water according to GOST 6709−72 or deionized water and reagents qualification hç, unless other qualifications or special for this analysis, the method of its purification.

4. Deionized water, distilled passing through the chromatographic column filled with cation exchanger KU-1, or equivalent anion exchange resin an-1 or similar.

5. Sample the sample analyzed and the material used for the preparation of samples and comparison of standard solutions weighed with an accuracy of not more than 0,00025 g. Sample of the sample and comparison samples during the spectral analysis allowed to weigh with accuracy up to 0,002 g.

(Changed edition, Rev. N 1, 2).

6. In the expression «diluted 1:1, 1:2, etc.» the first digits indicate the volume of the acid, or any solution, the second volume of the water.

7. The expression «oxide of rare earth element (REE oxide), net at the designated impurities» means those impurities not detected by the method of analysis is regulated by the standard.

(Changed edition, Rev. N 1, 2).

8. When chemical-spectral determination of impurities of oxides of rare earth elements rare earth metals and their oxides before every ten analyses carried out control experience performing all stages of the analysis in the absence of base. All reagents for extraction-chromatographic separations are prepared in quantities sufficient for 11 (or more) divisions. The contents of the designated impurities in a control experiment should be less than the minimum detectable given in the relevant standard. Otherwise, the reagents are replaced.

(Changed edition, Rev. N 2).

9. Verify the operation of extraction-chromatographic column may be performed by the method of radioactive indicators in the application.

10. The transfer of the samples of rare earth metals in oxide is as follows: a portion of the analyzed metal except cerium, weighing 100−300 mg was placed in a quartz Cup (when defining a silicon — platinum) with a capacity of 30−50 cm, add 3−5 cmof nitric acid (1:1) was dissolved at room temperature, and then when heated, is evaporated to wet salts, treated twice with distilled water, each time mpariwa solution to dryness; the dry residue is heated to remove oxides of nitrogen and calcined in a muffle furnace at 900−950 °C for 1−2 h; a portion of the cerium weight of 100−300 mg was placed in a quartz Cup (when defining a silicon — platinum), are oxidized by heating on the hotplate and calcined in a muffle furnace at 900−950 °C for 1−2 h.

(Changed edition, Rev. N 1).

11. Allowed the use of other methods if their metrological characteristics are not inferior to the characteristics of the methodologies included in the present collection.

12. If the text of the standard tables that specify multiple analytical line pairs for the same range of the designated contents is allowed to use any pair.

13. Allowed the use of other equipment, materials, utensils and reagents (including foreign) subject to obtaining the metrological characteristics are not worse than specified in relevant standard methods of analysis.

14. Discrepancies in the results of parallel measurements and results of analyses at the 0.95 confidence level should not exceed the values permitted discrepancies listed in the relevant standard methods of analysis.

(Changed edition, Rev. N 2).

15. (Deleted, Rev. N 2).

16. When calculating the results of the polarographic definitions of sulfur all heights of peaks counted at the same instrumental sensitivity polarograph.

17. The standards are permitted discrepancies for several values of the range of the designated contents. Permitted discrepancies for the other values of the specified band calculated using linear interpolation.

18. To control the accuracy of analysis results using standard samples of the composition rare earth metals and their oxides, close to the chemical composition of the analyzed samples.

For methods of analysis in which the discrepancy between the results calculated as the difference between the result of analysis considered accurate if the absolute value of the difference of analysis results and certified values at a confidence level of 0.95 does not exceed ,

where is the accuracy evaluation.

 — the permissible discrepancy of the results;

,

where is 1.96 (at p = 0.95) — quantile of the normal distribution;

 — the coefficient whose values for 0.95 and parallel definitions are given in the table.

For methods of analysis in which the discrepancy between the results calculated as a ratio, the result of the analysis WITH considered accurate if the ratio of the analysis result and certified value (calculate the ratio of largest to smallest) at a confidence probability of 0.95 does not exceed

.

Use industry-standard samples of the composition rare earth metals and their oxides and standard samples of enterprises certified in accordance with GOST 8.315−97.

To control the accuracy of analysis results obtained by the spectral method, which provides pre-mixing of the analyte with the graphite powder, allowed the use of a standard sample of composition of graphite powder (NG-27пр) GSO 2820−83.

In the absence of standard samples of composition accuracy control carried out as given below.

(Changed edition, Rev. N 2).

18.1. The accuracy of the analysis when using photometric, fluorescence, nephelometric and polarographic methods of analysis control method supplements.

The Supplement should be 2−3 times higher than the contents determined by the impurities in the sample , while if the lower limit of the designated contents, the Supplement should be 2−3 times the value .

The results of the analysis are considered accurate if the difference between (a) the calculated (the content of impurities determined in the sample plus additive ) and found values at confidence probability of 0.95 does not exceed the value calculated by the formula

,

where  — the permissible variation for ;

 — the permissible variation for .

The permissible differences given in the relevant standard methods of analysis. The value must not exceed the values where the upper limit is determined by the contents specified in the relevant standard.

18.2. The accuracy of the analysis results when using spectral, fiery photometry, luminous, activation, chemical-spectral and chemical activation methods of analysis control for each user-defined impurities in the transition to a new set of samples or standard comparison solutions.

For this purpose the same samples containing the designated impurity in a controlled range of concentration, using the old () and new (n) sets of samples of comparison or standard solutions get four test results and calculate average geometrical value and .

Then find the ratio of the larger of the obtained values and to a lesser. The results of the analysis are believed to be accurate, if the ratio does not exceed the square root of the allowable discrepancies in the results from both analyses are given in the relevant standard for the maintenance of equal .

Accuracy control is carried out for each interval between the neighbouring content references on a rolling basis for analysis of appropriate samples.

18.3. It is allowed to control the precision of analysis results by comparison with analysis results obtained in another standardized method. Discrepancies of the analysis results from both methods, with a probability of 0.95 should not exceed the value calculated by the formula

,

where  — the allowable difference given in the standard for controlled method;

 — the allowable difference given in the standard for the other standardized method.

18.1−18.3. (Changed edition, Rev. N 1, 2).

19. In the analysis of the sample of metal in GOST 23862.19−79, GOST 23862.21−79-GOST 23862.36−79 result rely on the content of metal impurities in it.

In the analysis of the sample oxide result rely on the content of metal impurities in it.

20. Allowed preparation of samples of comparison for the spectral analysis with the use of other quantities of the mixed substances, and also other combinations of the designated impurities while maintaining the values of the mass fraction specified in the relevant standard methods of analysis.

(Changed edition, Rev. N 1, 2).

21. REE oxide prior to use is calcined in a muffle furnace at 900 °C to constant weight.

22. Safety requirements for analyses of rare earth metals and their oxides — according to normative-technical documentation. The procedure and training in operating safety — according to GOST 12.0.004−90.

21, 22. (Added, Rev. N 1).

23. Boats, spatulas and other devices for the taking of portions with cotton wipe 0.3−0.5 g moistened with alcohol (0.5 cmper sample); mortars and pestles pre-wash with water then wipe it with cotton wool 0.5−1 g moistened with alcohol (3.5 cmby 1 sample); a support for the electrodes, tweezers, holders, electrodes are rubbed with a wool 0.5−1 g moistened with alcohol (3 cm).

With stirring to maintain the mixture in the pasty state, the alcohol and add 1 cmto 1 g of mixed substances.

(Added, Rev. N 2).

APP
Mandatory

CHECK THE CORRECT OPERATION OF EXTRATION-CHROMATOGRAPHIC COLUMN BY THE METHOD OF RADIOACTIVE INDICATORS

Use the following radioactive isotopes REE: lanthanum-140, cerium-141, neodymium-147, samarium-153, europium-152, europium-152m, gadolinium-159, terbium-160, dysprosium-165, holmium-166, erbium-171, thulium-170, ytterbium-175, lutetium-177.

Radioactive isotopes produced by irradiation of the respective oxides of REE, containing not more than 1·10% of each of the nearest neighbors of the REE, in a nuclear reactor with thermal neutron flux of 1.2·10n/cm·C for 20 h. Each of the irradiated oxides are placed separately in beakers with a capacity of 50 cmand was dissolved with heating in 7 mol/DMhydrochloric acid. Each solution is diluted with 7 mol/DMhydrochloric acid to each solution and the count rate was (1−5)·10pulses/min./5 cm(control solutions). Prepare at least 15 cmof each control solution.

The count rate for each solution change the setup for the integrated account, consisting of the counting device ПСО2−2em and scintillation sensor LGD with crystal Nal (T1) (with well), or similar device, providing a change of activity of radioactive isotopes, REE.

The solution is directed to the measurement, is placed in a glass box (type ST 24/10) with a capacity of 18 cm(boxes of count rate measurement).

Check the correct operation of the extraction-chromatographic column is performed as follows.

A portion of the analyzed oxides of REE (the weight of the portion specified in GOST 23862.7−79-GOST 23862.9−79, GOST 23862.18−79 sec. 4) is placed in a beaker with a capacity of 50 cm, add 5 cmreference solutions containing appropriate radioactive isotopes, REE (see table), 0.5 cmof hydrogen peroxide and heated until complete dissolution of the oxide. The solution is evaporated to wet salts, which dissolve in hydrochloric or nitric acid, volume and concentration of which are specified in GOST 23862.7−79-GOST 23862.9−79, GOST 23862.18−79 sec. 4.

The resulting solutions passed through an extraction-chromatographic column. Next, the column is washed with eluting solutions, the compositions of which are given in GOST 23862.7−79-GOST 23862.9−79, GOST 23862.18−79 sec. 4. Engineering work on the column specified in GOST 23862.7−79 sec. 3.

A portion of the eluate volume equal to the free volume of the sorbent (see GOST 23862.7−79-GOST 23862.9−79, GOST 23862.18−79 sec. 4), collected in measuring cylinder and discard. Next, the eluate is collected in glass vials in portions of 5 cmand determine the per serving the presence of the radioactive isotope of re (change of count rate) and the base element (see GOST 23862.7−79 sec. 3). Elution is continued until the complete leaching of radioactive elements from the column.

Portions of the eluate, dedicated to revealing the base is transferred to the evaporator, is evaporated to a volume of 5 cmand placed in a box for count rate measurement (concentrate 1).

The portions of eluate allocated after the removal of foundations from the column, transferred to an evaporator, evaporated to a volume of 5 cm(concentrate 2).

Concentrates 1 and 2 and 5 cmreference solutions of radioactive isotopes of re, eye-catching before and after the analyzed framework (see table), is placed separately into jars for measuring the speed of the account and conduct measurement.

Mass fraction of selected REE () in percent is calculated by the formula

,

where is the count rate for a solution of the concentrate, pulse/min;

 — the count rate for test solution corresponding radioactive isotope of re, imp/min.

Column considered usable if the number of selected REE not less than given in the table.

APP. (Changed edition, Rev. N 2).