Chemistry Doctoral Exam: Thermodynamics of Critical Rare Earth Minerals

About the event

Presenter: Margaret Reece

Degree: Doctor of Philosophy

Chair: Xiaofeng Guo

Title: Thermodynamics of Critical Rare Earth Minerals

Abstract:
Rare earth elements are a critical resource for advancing technologies, including nuclear waste applications. Economically minable sources of this element group is limited, and the determination of geologic behavior applied to find viable deposits is a large task that requires an in-depth understanding of thermodynamic behavior of involved species. A variety of mineral structures that host these elements were studied for derivation of thermodynamic properties that relate to the geologic stability, but also natural behaviors and potential applications as nuclear wastes. Solid phase thermodynamic characterization was employed to determine surface characteristics of pyrochlore minerals, aqueous phase solubility studies were performed in carbonate-bearing solutions for the common source minerals of monazite and bastnäsite, and solid-solution series were studied structurally and calorimetrically to preliminarily characterize natural solid-solution phosphate minerals. The solid phase characterizations included comparisons of energetics to cationic radii. Aqueous carbonate complexes were identified in Nd-carbonate systems bearing phosphate and fluoride. This information will aid in the genetic modeling of rare earth minerals and the behavior of mineral waste hosts in extreme conditions.