Continuous extraction and separation of Am(III) and Cm(III) using a highly practical diamide amine extractant

A highly practical diamide-type extractant, which is an alkyl diamide amine with 2-ethylhexyl alkyl chains (ADAAM(EH)), was investigated for the mutual separation of Am(III) and Cm(III). ADAAM(EH) is a multidentate ligand with one soft N-donor atom and two hard O-donor atoms as part of its central frame. This tridentate arrangement of donor atoms provides selective binding to Am(III) compared to that with Cm(III) in highly acidic media (1.5 M HNO3), resulting in separation factors of up to 5.5. A continuous liquid–liquid extraction and stripping test was conducted using a multistage countercurrent mixer-settler extractor with ADAAM(EH) in n-dodecane. In this test, the separation of Am(III) and Cm(III) was achieved with very high yield.