Frequency and atomic mass based selective electrochemical recovery of rare earth metals and isotopes

Rare earth metals (REMs or lanthanides) are highly useful in applications such as gas sensors, hybrid vehicles, defense equipment, fluorescent and LED lights, metal alloys, as well as in the production of electrical assemblies and associated magnets. The energy of 4f electrons of lanthanides is relatively less than that of outer valence electrons. In other words these electrons are localized and part of the ionic core. In addition, these 4f electrons do not directly participate in compound forming processes. This is a main cause for the difficulty in chemically separating similar lanthanides. One possible separation technique that utilizes the effect of atomic mass based dispersion, involves the application of a potential with different oscillating frequencies. At lower oscillating frequency, the range of mass distribution of REMs deposited is greater than that at higher frequency. In this paper, we present a step-by step approach and formulation to electrochemically separate REMs.