Date of Award

2022-12-01

Degree Name

Doctor of Philosophy

Department

Materials Science And Engineering

Advisor(s)

Guikuan Yue

Abstract

Experimentation was performed on molybdenite slurry by using ultrasonication to elucidate the effects of ultrasonic-induced bubble cavitation on the grade, recovery, and gangue reduction during small-scale flotation tests and was followed by a topographical analysis of quartz particles using SEM. Ultrasonic waves at 20-80 kHz that propagate through a liquid medium cause microbubbles to form, grow, and implode. The cavitation bubble's implosion causes brief extreme local conditions where temperatures can reach 5,000 K and pressures of 1,000 bar. The resulting microjets create mechanical and chemical changes to the system and were directed at improving flotation dynamics in these experiments. Through experimentation with a float cell immersed in an ultrasonic bath as well as the utilization of an ultrasonic probe, a clear reduction in gangue recovery was found after subjecting the slurry to a 2-minute pretreatment of ultrasound at 24 kHz and continuing for the duration of an 8-minute test. While the ultrasonic bath at 37 kHz did not reveal clear improvements, the ultrasonic probe embedded directly into the slurry did show benefits to gangue reduction and molybdenite grade in the concentrate, while the process did slow the kinetics of flotation. Subjecting the slurry to only a pretreatment of ultrasound revealed similar results to the testing involving using the probe for the entire duration of the float test. The effects of ultrasonication in regard to its deagglomeration capabilities is suspected as the cause of these results. While gangue is released from agglomerates and allowed to be rejected in the system, fine molybdenite particles benefit from agglomeration. A topographical survey of quartz particles using an SEM revealed craters and dimples in ultrasonicated slurry, potentially causing a reduction in contact angle and reduced quartz floatability.

Language

en

Provenance

Received from ProQuest

File Size

116 p.

File Format

application/pdf

Rights Holder

Wayne Alexander Campbell

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