Field-effect separation of rare earth elements in gelatin-supported media

Abstract

The unique optical, electronic, and magnetic properties of the Rare Earth Elements (La-Lu + Sc, Y) have led to a significant increase in their demand by a wide variety of industries. This, coupled with the significant difficulty associated with their extraction, separation, and purification, has resulted in a strong interest in replacing the traditional solvent extraction with a new approach. In response, a new technology called “Field-Effect Separation” (FES) has been developed, which utilizes differences in the magnetic susceptibilities of ions in a strong field to separate them from one another. While it has been demonstrated that this approach can work, it is necessary to more fully understand and optimize the separation of elements. The approach taken to study this was to suspend a solution of REE ions in a firm gelatin, separating them using a strong magnet, freezing the sample to preserve separation, and taking fine slices to analyze the concentration of ions at different spatial positions relative to the magnet as well as different times relative to the beginning of the magnetic field exposure. The results show a significant concentration effect for the magnetically susceptible REEs near the magnet's surface, while the non-susceptible ions seem relatively unconcentrated by the magnetic field. Additionally, among the susceptible REEs, at certain, short separation timescales, a significant stratification of REEs was observed. This suggests that the REEs can be separated from one another using FES assuming a correct time and length scale can be selected for the system.