Wan Wang

Date of Graduation

2017

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Mining Engineering

Committee Chair

Felicia F Peng

Committee Co-Chair

William M Hart

Committee Member

John A Herbst

Committee Member

Lian-Shin Lin

Committee Member

Yi Luo

Abstract

Froth flotation is one of the most important methods in mineral processing. Previous studies have found that using cavitation bubbles reduces both energy consumption and operating costs. Hydrodynamic cavitation is the most economical method used for creating tiny bubbles for flotation. In this study, the efficiency of cavitation bubble generating devices and their geometry design is analyzed using computational fluid dynamics (CFD).;To optimize the geometric design of the venturi tube, a response surface method was conducted for evaluating the effect of six important parameters affecting the efficiency of the venturi tube. Critical velocities of cavitation of different designs were compared. The CFD model was validated by comparing it with previous experimental work.;Population Balance Module (PBM) was developed to analyze the bubble size distribution of particles for the secondary phase. This module includes the rates of nucleation, growth, dispersion, aggregation, and breakage. A mathematical model was created and written as User Defined Functions (UDF) code and complied with ANSYS-FLUENT, to calculate the nucleation rate for the PBM model. In order to understand the interactions of bubble size distribution with particle size distribution, a 200 microm and a 400 microm diameter ball were added to the venturi grid. The CFD results found were consistent with experimental measurement results.;Different orders of the packed column and venturi tube in series were tested. The first design placed the packed column first, then the venturi tube second. The second design placed the venturi tube first, then the packed column second. Vapor volume of fractions and bubble sizes generated with a scale up venturi and multiple lab-scale venturis were analyzed. The results and recommendations of this study will provide more optimum yield in industry.

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