PROCESS FOR OBTAINING MOLYBDENUM FROM MOLYBDENUM SOLUTIONS COMPRISING ALKALI AND EVENTUALLY URANIUM CARBONATES, SULFATES, HYDROXIDES OR BICARBONATES

摘要

A process for obtaining molybdenum as a useful product from aqueous solutions to be purified, according to claim 1 of French patent No. 2 404 601, which contain, besides said molybdenum, alkali metal carbonate, sulphate, hydroxide or hydrogen carbonate and which may also contain uranium, and inorganic and/or organic impurities, said solutions being treated at a temperature which is at most equal to the boiling temperature by means of lime to convert the alkali metal carbonate into hydroxide and to precipitate the insoluble calcium salts formed, then separating and washing the first precipitate which essentially contains calcium carbonate, from an alkali metal hydroxide-enriched liquor, which is concentrated by evaporation at the same time as the washing liquor of the first precipitate, to produce an alkali metal hydroxide content which is at most equal to 50%, to produce a second precipitate formed by a mixture of alkali metal molybdate and sulphate, characterized in that said solid mixture is dispersed in an acid aqueous liquor which is heated at from 120 DEG C. to 250 DEG C. under pressure to cause precipitation of anhydrous Mo03 which is subsequently separated from the mother liquor which essentially contains alkali metal sulphate.