Solvent extraction of tin in nitric acids: evaluation of multiple extractants

Abstract

In this study, the solvent extraction behavior of tin (Sn), specifically ¹²⁶Sn, from high-level radioactive waste was evaluated using six different extractants in a HNO₃ system. Among the tested extractants, N,N-Didodecyl-2-hydroxyacetoamide (HAA) exhibited higher efficiency, still not sufficient for industrial implementation. In systems where HCl was added to HNO₃, both tributyl phosphate (TBP) and N,N,N,N’-tetra-2-ethylhexyl diglycolamide (TEHDGA) achieved D_Sn values greater than 1 at > 1 M HCl. However, due to practical challenges in industrial applications, HAA extraction in HNO₃ systems, particularly at low Sn concentrations (0.0008 M), may provide a more effective solution for Sn recovery.