Bench-Scale Test for Separation of Sr²⁺ and Nd³⁺ from HLLW Using TiBOGA

Abstract

A bench-scale test for the separation of strontium and trivalent lanthanides/actinides, using Nd³⁺ as a surrogate, from a simulated acidic high level liquid waste (HLLW) has been performed with a set of 10-mm centrifugal contactors using N,N,N′N′-tetra-iso-butyl-3-oxa-glutaramide (TiBOGA) as extractant. The test shows that Sr²⁺ and Nd³⁺ can be co-extracted from the HLLW and then separated from each other by step stripping. The results indicate that 99.99% of Sr²⁺ and Nd³⁺ can be removed from the HLLW, and less than 0.01% of Nd³⁺ remains in Sr²⁺ product stream and 0.1% of Sr²⁺ in Nd³⁺ stream. In HNO₃ solutions −0.2 M TiBOGA in 40% octanol/kerosene system the mass transfer stage efficiencies of HNO₃ and Sr²⁺ have also been studied on a single-stage 10-mm centrifugal contactor.

Keywords:

• high level waste
• neodymium
• separation
• strontium
• TiBOGA

ACKNOWLEDGEMENTS

The experiment work was conducted at Institute of Nuclear and New Energy and Technology (INET): Tsinghua University, Beijing, and supported by the State High-Tech Development Plan (863 program, China): No. 2009AA050703. The preparation of this manuscript was supported by the Fuel Cycle Research and Development Program (Aqueous Separations: Thermodynamics and Kinetics) of Office of Nuclear Energy, under U.S. Department of Energy Contract No. DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory (LBNL).

Notes

*: Calculated efficiency is greater than 100%, likely due to the experimental uncertainty.

*: Calculated value is 100%, due to the concentrations in the raffinate lower than the detection limits.

-: Either the value is less than 0.01% or the concentration is lower than the detection limit.