Actinide(3)/lanthanide(3) partitioning using n-Pr-BTP as extractant: extraction kinetics and extraction test in a hollow fiber module

2,6-di(5,6-di-propyl-1,2,4-triazine-3-yl)pyridine (n-Pr-BTP), first developed in our laboratory, is a very promising extractant for the effective separation of actinides(III) from lanthanides(III). It is able to extract actinides(III) with usable distribution coefficient from 1-2 molar nitric acid selectively over lanthanides(III). The Am(III)/Eu(III) separation factor is approx. 135. The performance of this extractant is further elucidated by kinetic investigations and a counter-current extraction experiment in a hollow fiber module (HFM). The kinetic investigations were performed in a stirred cell. The fact that extraction rate is independent of stirring speed reveals a slow chemical complexation reaction. The HFM extraction test on americium(III)/fission lanthanides(III) separation showed good hydrodynamic behavior. Depending on aqueous flow rate, which was varied, up to 94% americium could be removed from the feed phase. Lanthanide co-extraction was in the range of 1%. (author)