COPRECIPITATION OF SELENIUM AND TELLURIUM WITH METALLIC HYDROXIDES (in Russian)
An attempt is made to explain the effect of the nature of the hydroxide carrier used to coprecipitate small amounts of Se and Te. Ammonia was added drop by drop to an equivalent amount of metul nitrate salt in 0.5N NH/sub 4/NO/sub 3/ solution, until precipitation of the hydroxide is complete. Se/sup 75/ and Te/ sup 127/ were used as tracers. The pH was measured to combination rat 0.05 pH units by a platinum-hydrogen electrode. The differences in chemical behavior between Se and Te become more manifest at high pH. The results show that the carrying of Se increases with an increase in ionic radius of the metal which is precipitated as the hydroxide in the order Al /sub 2/ were ob Ti /sub 2/ were ob Bi /sub 2/ were ob Pb. The higher the valence of the metallic carrier ion the greater the carrying of Se for two metals with the same ionic radius. Ceric hydroxide has been found to be the most suitable carrier for Se(IV), but Ce, like all the other metallic hydroxides, does not carry Se(VI). A series of experiments showed that Fe(OH)/sub 3/ carries both Te(IV) and Te(VI). A new method of separating Te and Se was developed on the basis that Te(VI) is carried on Fe(OH)/sub 3/ but Se(VI) is not. A series of comparative experiments with beryllium hydroxi de carrier at a pH of 7.5 to 9.5 showed that the carrying falls off in the following order: Te(VI) /sub 2/ were ob Te(IV) /sub 2/ were ob Se(IV) /sub 2/ were ob Se(VI). Carrying decreases with increasing valence for Se, but increases with tncreasing valence for Te. The coprecipitation of Se and Te depends on the nature of the anion in solution and increases with a decrease in the dissociation of the corresponding acids. Preformed precipitates do not carry Se or Te as well as direct precipitation of the metallic hydroxide in the presence of Se or Te. (TTT)
- Research Organization:
- All Union Mining-Metallurgical Scientific Research Inst. of Non- Ferrous Metals
- NSA Number:
- NSA-14-019037
- OSTI ID:
- 4186413
- Journal Information:
- Zhur. Neorg. Khim., Journal Name: Zhur. Neorg. Khim. Vol. Vol: 5
- Country of Publication:
- Country unknown/Code not available
- Language:
- Russian
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Related Subjects
ALUMINUM
AMMONIA
AMMONIUM COMPOUNDS
ANIONS
BERYLLIUM HYDROXIDES
BISMUTH
CERIUM HYDROXIDES
CHEMICAL REACTIONS
CHEMISTRY
ELECTRIC CHARGES
ELECTRODES
HYDROGEN
HYDROXIDES
IRON HYDROXIDES
LEAD
METALS
NITRATES
PLATINUM
PRECIPITATION
SELENIUM
SELENIUM 75
SELENIUM HYDROXIDES
SOLUTIONS
TELLURIUM
TELLURIUM 127
TITANIUM
TRACER TECHNIQUES