Surface Spectroscopic Investigation of Rare Earth Minerals Flotation
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Author(s)
Primary Supervisor
Hope, Gregory
Other Supervisors
Bernhardt, Debra
Year published
2016
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This thesis describes fundamental studies of the surface interactions between rare earths and the collector hydroxamate to obtain a mechanistic understanding of the flotation process. A model and systematic investigation has been undertaken in order to ascertain the flotation mechanism and optimise flotation response and selectivity. Major constituent components (rare earth oxides, minerals and gangue minerals) in the flotation system were fully characterized individually prior to the interaction investigations. Six rare earth hydroxamate model compounds have been synthesized to characterize the surface chemical bonding. A ...
View more >This thesis describes fundamental studies of the surface interactions between rare earths and the collector hydroxamate to obtain a mechanistic understanding of the flotation process. A model and systematic investigation has been undertaken in order to ascertain the flotation mechanism and optimise flotation response and selectivity. Major constituent components (rare earth oxides, minerals and gangue minerals) in the flotation system were fully characterized individually prior to the interaction investigations. Six rare earth hydroxamate model compounds have been synthesized to characterize the surface chemical bonding. A model mineral thin film was also synthesized and investigated with the hydroxamate collector. For the vibrational characterization of the rare earth oxides, this thesis has adopted multiple radiation sources (wavelengths of 325 nm, 442 nm, 514 nm and 632.8 nm) scanning Raman shifts from 100 cm-1 – 5000 cm-1. It has been demonstrated that each individual rare earth oxide has similar, but distinct vibrational and electronic properties including Raman and fluorescence spectra. Nd, Er and Ho can be identified through their fluorescence emissions that do not overlap the Raman spectra. It is possible to develop a fast detection technique for these rare earths using their fluorescence emissions spectra in mineral processing. The characterization of natural mineral bastnaesite and monazite demonstrated that the ore exhibits localized enrichment zones of the rare earths of sizes from 1 µm - 5 µm. The results from atomic force microscopy and magnetic atomic force microscopy have confirmed the enrichment zones are smaller than the present grinding sizes for flotation. It would be of interest to re- examine the grinding sizes in practice in order to maximise the liberation of minerals.
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View more >This thesis describes fundamental studies of the surface interactions between rare earths and the collector hydroxamate to obtain a mechanistic understanding of the flotation process. A model and systematic investigation has been undertaken in order to ascertain the flotation mechanism and optimise flotation response and selectivity. Major constituent components (rare earth oxides, minerals and gangue minerals) in the flotation system were fully characterized individually prior to the interaction investigations. Six rare earth hydroxamate model compounds have been synthesized to characterize the surface chemical bonding. A model mineral thin film was also synthesized and investigated with the hydroxamate collector. For the vibrational characterization of the rare earth oxides, this thesis has adopted multiple radiation sources (wavelengths of 325 nm, 442 nm, 514 nm and 632.8 nm) scanning Raman shifts from 100 cm-1 – 5000 cm-1. It has been demonstrated that each individual rare earth oxide has similar, but distinct vibrational and electronic properties including Raman and fluorescence spectra. Nd, Er and Ho can be identified through their fluorescence emissions that do not overlap the Raman spectra. It is possible to develop a fast detection technique for these rare earths using their fluorescence emissions spectra in mineral processing. The characterization of natural mineral bastnaesite and monazite demonstrated that the ore exhibits localized enrichment zones of the rare earths of sizes from 1 µm - 5 µm. The results from atomic force microscopy and magnetic atomic force microscopy have confirmed the enrichment zones are smaller than the present grinding sizes for flotation. It would be of interest to re- examine the grinding sizes in practice in order to maximise the liberation of minerals.
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Thesis Type
Thesis (PhD Doctorate)
Degree Program
Doctor of Philosophy (PhD)
School
School of Natural Sciences
Copyright Statement
The author owns the copyright in this thesis, unless stated otherwise.
Item Access Status
Public
Subject
Rare earths
Collector hydroxamate
Rare earth oxides
Raman spectra