Method for purifying the uranium from a natural uranium concentrate

摘要

A method with which uranium from a natural uranium concentrate may be purified, including
a) extracting the uranium present as 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 which contains an extractant in an organic diluent;b) washing the organic phase obtained at the end of step a), with an aqueous phase A2; andc) stripping the uranyl nitrate of the organic phase obtained at the end of step b), by circulating this organic phase in an apparatus, as a counter current against an aqueous phase A3.;The extractant is an N,N-dialkylamide and the ratio between the flow rate at which the organic phase obtained at the end of step b) and the aqueous phase A3 circulate in the apparatus where step c) occurs, is greater than 1.

主权项

1. A method for purifying the uranium of a natural uranium concentrate containing at least one impurity selected from thorium, molybdenum, zirconium, iron, calcium, and vanadium, the method comprising:
a) extracting the uranium present as uranyl nitrate from an aqueous phase A1 resulting from a dissolution of the natural uranium concentrate in nitric acid, said step of extracting comprising putting the aqueous phase A1 in contact with an organic phase non-miscible with water, which contains an extractant in an organic diluent, and then separating said aqueous and organic phases; b) washing the organic phase obtained at the end of step a), said step of washing comprising putting the organic phase obtained at the end of step a) in contact with an aqueous phase A2, and then separating said organic and aqueous phases; and c) stripping the uranyl nitrate from the organic phase obtained at the end of step b), said step of stripping comprising circulating the organic phase obtained at the end of step b) in an apparatus, as a counter current to an aqueous phase A3, and then separating said organic and aqueous phases, wherein the extractant contained in the organic phase is an N,N-dialkylamide and a ratio between flow rates at which the organic phase obtained at the end of step b) and the aqueous phase A3 circulate in the apparatus of step c) is greater than 1.