Date of Award

Fall 2019

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Materials Science

Committee Chair

Courtney Young

First Advisor

Hsin-Hsiung Huang

Second Advisor

Avimanyu Das

Third Advisor

Royce Engstrom

Fourth Advisor

Stephen Sofie


Rare earth elements (REEs) are strategic materials of extreme importance to both military and civil applications. REEs are mined and processed because of their criticality. End of life rare earth metals are recycled for efficient use of natural resources and also to ensure supply of these critical raw materials. By using hydro- or pyro-metallurgi­cal approaches, REEs can be processed from mined ore or recycled from magnets and other materials as rare earth oxides, fluorides and chlorides. Typically, rare earth oxides are dissolved in a molten halide bath, converted to metal by electrolysis at elevated temperatures, and then recovered as a liquid upon tapping and, later, as a solid upon casting and cooling. This research focuses on advanced separations which differences in physical and chemical properties of the molten bath are taken advantage of to yield effective recovery of neodymium metal. To achieve the neodymium metal recovery, a unique approach using novel potential (E)-pO2- diagrams coupled with cyclic voltammetry (CV) and electrowinning (EW) was employed. Another aspect includes the use of a novel hydrometallurgical method to recycle neodymium magnets to produce neodymium fluoride so it could also become a feedstock to the molten bath considered in this work.


A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy: Materials Science