Patent ID: 9255337
Filing Date: 2016-02-09
CPC Classification: C25C

Claim Text:
1. A method of extracting rare earth metal from mixtures comprising rare earth metal compounds, the method comprising: providing a first molten salt mixture comprising a group II fluoride and a rare earth metal fluoride present in a first ratio; continuously providing a feedstock mixture comprising a rare earth metal oxyfluoride and a group II oxide present in a second ratio, the second ratio being such that chemical conversion of the rare earth metal oxyfluorides and group II oxides to rare earth oxides, group II fluorides, and rare earth fluorides generates group II fluorides and rare earth metal fluorides in about the same ratio as the first ratio; combining the first molten salt mixture and the feedstock mixture to form a reaction mixture, the reaction mixture comprising oxide ions; providing a first cathode in electrical contact with the reaction mixture; providing an anode, wherein the anode is in ion-conducting contact with an oxide ion-conducting membrane, and the oxide ion-conducting membrane is in ion-conducting contact with the reaction mixture; generating a potential between the anode and the first cathode to reduce the metallic species of the rare earth metal oxyfluoride at the first cathode, transport oxide ions across the oxide ion-conducting membrane, and oxidize the oxide ions at the anode; and collecting the reduced rare earth metallic species.