Group-Separation of Rare-Earth Elements by Use of Electrodialysis with a Complexing Agent

Abstract

Cerium was separated from the cerium-gadolinium-itorium system and the cerium-lanthanum group and praseodymium-neodymium group were separated from the cerium-lanthanum-praseodymium-neodymium system by electrodialysis using a complexing agent. Separation of each rare earth metal proceeded well under the condition of 50% complexation rate, and cerium or cerium-lanthanum group was concentrated in the concentration chamber. The experimental results could be well explained by a model based on the Nernst-Planck equation, which takes into account solution selectivity, membrane selectivity and intramembrane migration. In addition, the optimum complexing agent concentration and multi-step separation operation were investigated using the same model, and the separation efficiency was improved by setting the concentration of the complexing agent to the concentration of the metal species to be masked and performing the multi-step operation. Shown that there is a possibility of increase.