Date of Award

Spring 2018

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Materials Science

Committee Chair

Courtney Young

First Advisor

Jerome Downey

Second Advisor

Jack Skinner

Third Advisor

Hilary Risser

Fourth Advisor

Paul Gannon

Abstract

A high-fidelity kinetic model was developed to identify and elucidate the effects of varying principle froth flotation parameters on the sub-processes that occur within and between the flotation zones. Whereas traditional models fail to adequately address froth recovery and recovery by entrainment, the high-fidelity model defines these phenomena based on an improved understanding of the pulp/froth interface. Solution chemistry considerations that govern rare earth mineral separation by flotation were identified, characterized, and optimized. Application of novel surfactants such H205 and salicylhydroxamic acid (collectors) and dimethyl glycol monobutyl ether (depressant) was evaluated to define optimal flotation conditions. The effect of pressure on fine particle entrainment was also studied because, with certain rare earth mineral ores, sufficient mineral liberation is not achieved at nominal flotation particle sizes. Pressure can be applied to produce the small bubble sizes required for fine particle flotation. The correct solution chemistry for flotation (and not entrainment) can then be utilized for the selective recovery of rare earth minerals.

The predictive high-fidelity kinetic model was developed using experimentally derived and statistically significant rate equations and was confirmed through application to copper/molybdenum sulfide and rare earth mineral ore samples. The parametric models identified ideal flotation conditions that optimized the recovery of rare earth minerals using the novel collectors; when the same experiments were modeled using the high-fidelity kinetic model, recovery by entrainment was found to be significant. The effects of pressure on gas dispersion mechanisms, such as gas holdup, and how those mechanisms effect bubble size and kinetic parameters were determined.

Comments

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

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