Abstract: A process for recovering a rare earth element. The process includes adding water and a nonaqueous acid to an ionic liquid, and dissolving an oxide of a first rare earth element directly into the ionic liquid to form an ionic solution comprising at least about 0.1 weight percent water, the acid and an ion of the first rare earth element. The process further includes applying a potential to the ionic solution to deposit the first rare earth element onto an electrode as a metal.

Abstract: A surface-contact sensor includes a housing defining an opening, an ion-permeable membrane at the opening, a counterelectrode within the housing, and a reference electrode within the housing that is spaced apart from the current-collector. A current-collector pad includes a grommet support having a base and a lumen defining an opening. An ion-permeable membrane spans at least a portion of the opening of the grommet. The ion-permeable membrane is held in place by a gasket surrounding the lumen. A current collector, at least in one embodiment, is proximate to a portion of the ion-permeable membrane that spans the opening.