Using rare earth oxychlorides as precursors to prepare rare earth alloys through solid cathode electrolysis in molten CaCl2

Abstract

Rare earth oxychlorides were investigated for the first time as precursors to prepare rare earth alloys through solid cathode electrolysis in molten CaCl2, and to demonstrate this approach the electrochemical reduction of a LaOCl and NiO mixture to LaNi5 was performed. It was found that LaOCl is a good solid precursor of La because it neither absorbs water from the air nor reacts with the molten electrolyte. The electrode process consists of two simple and rapid steps: the reduction of NiO to Ni, followed by the reduction of LaOCl on the formed Ni, generating LaNi5. Moreover, as most of the rare earth elements have similar physicochemical properties and their oxychlorides are easily available, our findings may promise a general route for the preparation of rare earth alloys. Keywords: Solid-state electrochemistry, Rare earth oxychlorides, LaNi5, Molten salts, Electrolysis