Direct electrochemical conversion of metal oxides to metal by molten salt electrolysis: a review

Abstract

Little over a decade ago, Professor Derek Fray’s group at the University of Cambridge, UK, discovered that a solid metal oxide can be directly reduced to metal by cathodically polarising it in a molten salt electrolytic cell. The simple electrochemical process attracted worldwide attention and significant efforts have been made since then to study and develop the process for production of many metals/alloys from their oxides. The process, with necessary modifications, is being studied and adapted as a head-end step in the pyrochemical reprocessing of spent oxide nuclear fuels. This review discusses the solid-state electro-reduction process, its development and the present status in both public and nuclear domains.

Keywords:

• Electro-deoxidation
• FFC Cambridge process
• Calcium chloride
• Lithium chloride
• Actinide oxides
• Pyrochemical reprocessing
• Spent oxide nuclear fuel

Acknowledgement

This paper is a revised version of the paper published in the proceedings of Fray International Symposium on ‘Metals and Materials Processing in a Clean Environment’ edited by F. Kongoli, published by FLOGEN STARS OUTREACH, 2012.

The author wishes to express his thanks to Dr P. R. Vasudeva Rao and Dr K. Nagarajan for their support for the electro-deoxidation work and to Mr N. Sanil for his critical reading of the manuscript and useful suggestions.