Compounds with phosphine oxide and amine functions, useful as uranium (VI) ligands, and uses thereof, in particular for extracting uranium(VI) from aqueous solutions of sulphuric acid

A method for recovering the uranium present in an aqueous solution of sulphuric acid derived from the lixiviation of a uranium ore by sulphuric acid, comprising:

• a) an extraction of uranium, in oxidation state VI, from the aqueous solution, the extraction comprising contacting the aqueous solution with an organic phase comprising a compound of formula (I):
• in which:
• R1 and R2 represent, independently of one another, a saturated or unsaturated, acyclic hydrocarbon group comprising 4 to 12 carbon atoms;
• R3 represents a hydrogen atom;
• a saturated or unsaturated, acyclic hydrocarbon group comprising 1 to 12 carbon atoms and optionally one or more heteroatoms;
• a saturated or unsaturated, cyclic hydrocarbon group with 5 or 6 carbon atoms;
• or a saturated or unsaturated, 5- or 6-membered heterocyclic group;
• R4 represents a hydrogen atom or a saturated or unsaturated, acyclic hydrocarbon group comprising 1 to 12 carbon atoms and optionally one or more heteroatoms;
• R5 and R6 represent, independently of one another, a hydrogen atom;
• a saturated or unsaturated, acyclic hydrocarbon group comprising 1 to 12 carbon atoms and optionally one or more heteroatoms;
• a saturated or unsaturated, cyclic hydrocarbon group with 5 or 6 carbon atoms;
• or a saturated or unsaturated, 5- or 6-membered heterocyclic group;
• wherein R5 and R6 do not each represent a hydrogen atom;
• then separating the aqueous solution from the organic phase;
• and
• b) a stripping of uranium(VI) from the organic phase obtained at the end of a), the stripping comprising contacting the organic phase with an aqueous solution comprising at least one carbonate, then separating the organic phase from the aqueous solution.

A compound of formula (I):

• in which:
• R1 and R2 represent, independently of one another, a saturated or unsaturated, acyclic hydrocarbon group comprising 4 to 12 carbon atoms;
• R3 represents a saturated or unsaturated, acyclic hydrocarbon group comprising 1 to 12 carbon atoms and optionally one or more heteroatoms;
• a saturated or unsaturated, cyclic hydrocarbon group with 5 or 6 carbon atoms;
• or a saturated or unsaturated, 5- or 6-membered heterocyclic group;
• R4 represents a hydrogen atom or a saturated or unsaturated, acyclic hydrocarbon comprising 1 to 12 carbon atoms and optionally one or more heteroatoms;
• R5 and R6 represent, independently of one another, a hydrogen atom;
• a saturated or unsaturated, acyclic hydrocarbon group comprising 1 to 12 carbon atoms and optionally one or more heteroatoms;
• a saturated or unsaturated, cyclic hydrocarbon group with 5 or 6 carbon atoms;
• or a saturated or unsaturated, 5- or 6-membered heterocyclic group;
• wherein R5 and R6 do not each represent a hydrogen atom.