| abstract |
The invention relates to a method making it possible to purify the uranium from a natural uranium concentrate. Said method includes: a) extracting the uranium, present in the form of uranyl nitrate, in an aqueous phase A1 resulting from the dissolution of the natural uranium concentrate in nitric acid by means of an organic phase containing an extractant in an organic thinner; b) stripping the organic phase, obtained from step a), with an aqueous phase A2; and c) back extracting the uranyl nitrate from the organic phase, obtained from step b), by means of flowing said organic phase into an apparatus, in the opposite flow direction of an aqueous phase A3. The invention is characterized in that the extractant is an N,N -dialkylamide and in that the ratio between the flow rates of the organic phase, obtained from step b), and the aqueous phase A3 in the apparatus where step c) occurs is greater than 1. The invention is of use in the refinement of natural uranium concentrates produced by uranium mines. |