| 摘要 |
<p>Aq. solns. contg. carbonates, sulphates, hydroxide or bicarbonates of Na or K and at least one of V, U and Mo, together with mineral and organic impurities, are purified by treatment at >= b. pt. with lime in amt. (0.1-20) times the stoichiometri amt. for transforming the carbonates present into hydroxides, without taking account of the amt of time required to ppte. insol. metallic cpds. of Ca. The first ppte, is sepd. and washed. This contains CaCO3 and a mixt. of other organic and inorganic Ca salts. The remaining liquor is enriched in hydroxide. The mixt. of this liquor and the wash liquor from the first ppte. is concentrated by evapn. to >=50% hydroxide, to provoke formation of a second ppte. of Na2SO4 or K2SO4. The crystals are sepd. from the liquor which remains rich in hydroxide. In extraction of U, V and/or Mo from their ores. The aq. solutions remaining are purified of pollutants, so that they can be safely discarded, in compliance with stringent new regulations.</p> |
