High-efficiency lithium isotope separation by electrochemical deposition and intercalation with electrochemical isotope effect in propylene carbonate and [BMIM][DCA] ionic liquid

摘要

Li isotopes are of great importance in the nuclear industry and are generally produced by the environmentally hazardous column exchange process. Many separation techniques have been proposed to develop an environmentally-friendly and cost-effective separation method. Among all the proposed methods, the electrochemical deposition and intercalation method is of promising application in the future. However, no industrialization attempts have been made because of the lack of thorough research in this field. In this paper, the Li isotope separation tests were conducted with the electrochemical deposition and intercalation method and the experimental setup proposed in this research. To have a comprehensive understanding of the factors influencing performance, the effects of solvent and cathodic substrate were investigated with LiBF4 deposition tests on four substrates in two solvents. Experimental results show that the separation coefficient from the graphite substrate is consistent with the literature reported value. Other combinations of substrates and solvents yield better separation coefficients. For most of them, the separation coefficient may reach 1.09-1.10, which is the highest separation coefficient observed in various Li isotope separation tests in this study as well as in the literature reported to the best of the authors' knowledge. Moreover, a separation coefficient of 1.20 was achieved with the Ni-PC system. (C) 2020 Elsevier Ltd. All rights reserved.