Process for separating americum from other metallic elements present in an acidic aqueous or organic phase and applications thereof

A process for selective recovery of americium present in an acid aqueous phase containing, further to americium, other metal elements, characterized in that it comprises a process for separating americium from the other metal elements present in a phase P1, which comprises one or more operations each comprising putting the phase P1 in contact with a phase P2 which is not miscible with it, and then separating the phase P1 from the phase P2, one of the phases P1 and P2 being an acid aqueous phase and the other one of these phases being an organic phase which contains at least one extractant in an organic diluent, and is characterized in that the acid aqueous phase contains an ethylenediamine derivative fitting the general formula (I) hereafter:

• wherein A1, A2, A3 and A4, which are identical or different, represent a group of general formula (II) hereafter:
• wherein:
• either X represents a nitrogen or sulfur atom, in which case one of the R1, R2 and R4 represent a complexing group selected from the groups —COOH, —SO3H, —PO3H2, —CONH2 and —CON(CH3)2, while the other ones of R1, R2 and R4 represent independently of each other, a hydrogen atom or a group selected from the groups —OH, —NH, —N(CH3)2, —COOH, —COOCH3, —CON(CH3)2, —SO3H, —SO3CH3, —PO3H2, —PO(OCH3)2, —O(CH2CH2)n—OH and —O(CH2CH2)n—OCH3 wherein n is an integer equal to or greater than 1;
• or X represents a carbon atom bearing a hydrogen atom or a group R3, in which case one of R1, R2, R3 and R4 represents a complexing group selected from the groups —COOH, —SO3H, —PO3H2, —CONH2 and —CON(CH3)2, while the other ones of R1, R2, R3 and R4 represent, independently of each other, a hydrogen atom or a group selected from the groups —OH, —NH2, —N(CH3)2, —COOH, —COOCH3, —CONH2, —CON(CH3)2, —SO3H, —SO3CH3, —PO3H2, —PO(OCH3)2, —O(CH2CH2)n—OH and —O(CH2CH2)n—OCH3 wherein n is an integer equal to or greater than 1;
• or a salt thereof.