(732d) Selective Extraction of Rare Earth Elements from Scrap Magnets Via Membrane Solvent Extraction

Authors: 
Kim, D., Oak Ridge National Laboratory
Powell, L. E., Oak Ridge National Laboratory
Delmau, L. H., Oak Ridge National Laboratory
Peterson, E. S., Idaho National Laboratory
Herchenroeder, J., Molycorp Magnequench
Bhave, R., Oak Ridge National Laboratory

The use of rare earth elements (REEs) is widely prevalent in various energy applications such as rechargeable batteries, wind turbines, photovoltaic thin films, and fluorescent lighting. It is critical to ensure sufficient supply of the REEs to meet the fast growing demand in many high-tech industries. One of the approaches to increase the REE supply is to recover REEs from end-of-life products containing REEs. In view of this, a membrane solvent extraction (MSX) system utilizing hollow fiber membrane modules was developed to selectively extract REEs from neodymium-based scrap magnets from several leading industrial manufacturers. Two extractants, TODGA (tetraoctyl digylcol amide) and Cyanex 923 (trialkyl phosphine oxides), were evaluated to determine the distribution coefficient and selectivity for Nd (neodymium) and Dy (dysprosium). The effects of several experimental variables on REE extraction in the MSX system such as REE concentration, membrane configuration, and molar concentration of acid were investigated. The results of selective extraction of Nd, Dy, and Pr (Praseodymium) without co-extraction of non-REEs from NdFeB scrap magnets will be discussed along with characterization of the recovered REEs with X-ray diffraction, energy-dispersive X-ray spectroscopy, and inductively coupled plasma-optical emission spectroscopy.