New Insight into the Americium/Curium Separation by Solvent Extraction using Diglycolamides

The liquid–liquid extraction process called EXAm was developed by the CEA to allow the recovery of Americium alone from a PUREX raffinate. Americium is extracted from a highly acidic feed solution (HNO3 4–6 M) by a mixture of two extractants: DMDOHEMA and HDEHP. The Am/Cm selectivity is improved using a specific diglycolamide (TEDGA) as a selective aqueous complexing agent which retains preferentially Cm and heavier lanthanides in the aqueous phase. In this study, the impact of the lipophilicity and steric hindrance of several diglycolamides on the Am/Cm selectivity was investigated in order to understand the enhancement brought by TEDGA. For this purpose, liquid–liquid extraction and partitioning experiments were performed under various conditions.