Mono amides for the separation of neptunium from acidic feed

In the PUREX process, neptunium is distributed between the aqueous raffinate and the organic phase due to the variable oxidation states of the metal ion in the dissolver solution. While the extract mainly contains Np(VI), most of the neptunium distributed in the aqueous raffinate due to the presence of non extractable Np(V). Due to the long half life of ²³⁷Np (2.1 x 106 y), its separation from high level liquid waste can minimize the long-term surveillance of the vitrified waste blocks to a great extent. Monoamides, such as N,N'-dihexyl octanamide (DHOA) and Di-2-ethylhexyl isobutyramide (D2HiBA) are considered to be eco-friendly extractants (CHON type) and hence, have been extensively evaluated over the years as alternative extractants for actinides in the reprocessing industries. In the present paper, DHOA and D2EHiBA were used for the separation of neptunium from acidic feeds containing neptunium, plutonium and uranium