Abstract

Rare earth and actinide metals, critical to security, medicine, and the economy, have been processed through methods such as solvent extraction and electrorefining. To minimize radiological waste and improve yield, a 'chloride volatility' process--also known as the chlorination and volatilization process (CVP)--has been proposed and demonstrated for processing rare earths. The process takes advantage of the low vapor pressure of rare earth chlorides (<700 °C), CaCl2 was added to LaCl3 to lower the melting temperature. LaCl3 electrochemical behavior has not previously been studied in CaCl2. Cyclic voltammetry (CV) and square wave voltammetry (SWV) were applied to LaCl3 salts in CaCl2-LiCl and CaCl2 to study the metal ion behavior. Various electrode materials were compared at low CV scan rates (s-1) to determine compatibility with chlorine gas evolution. Experiments of eutectic LaCl3-CaCl2 were performed and analyzed to determine the efficacy of chlorine gas generation via electrolysis for the CVP. Through galvanostatic electrolysis, oxidation of chloride ions and subsequent chlorination of rare earth was demonstrated, with cerium chosen as the representative rare earth metal. Through a quadrupole mass spectrometer plumbed in line with the electrolytic cell, the quality of the generated gas was analyzed.

Degree

MS

College and Department

Chemical Engineering

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2022-08-01

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd12538

Keywords

rare earth, actinide, chlorine, molten salt, volatility, cyclic voltammetry, square wave voltammetry, diffusion coefficient, exchange current density, electron transfer coefficient

Language

english

Included in

Engineering Commons

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