PROCESS FOR THE VALORIZASTION OF URANIUM AND RARE EARTHS CONTAINED IN THE IMPURE UF.SUB.4 FROM THE EXTRACTION OF THE URANIUM OF PHOSPHORIC ACID

摘要

The invention relates to a process for upgrading uranium and rare earths contained in impure uranium tetrafluoride originating from the recovery of uranium from phosphoric acid, which consists in dissolving it hot in a nitric medium in the presence of an aluminum compound, treating the solution obtained with a solvent for extracting uranyl nitrate containing a phosphoric ester and separating from the desuranilized aqueous phase the solvent loaded with uranyl nitrate to be recovered. This process is characterized in that, with the aim of obtaining an easy separation of the desuranic aqueous phase from the extraction solvent for uranyl nitrate: a) the UF4 is dissolved in two stages at an appropriate temperature , the first step consisting in introducing insufficient quantities of nitric acid and of the aluminum compound to completely dissolve the impure uranium tetrafluoride and in keeping the suspension obtained with stirring for a time of at least 0.5 hour, the second step consisting in introducing the quantities of nitric acid and of the aluminum compound at least sufficient to dissolve the undissolved uranium in the first step and keeping the suspension stirred; and b) extracting the uranyl nitrate by bringing the aqueous medium coming from the dissolution of UF4 into contact with the solvent for extracting uranyl nitrate containing the phosphoric ester.