Browsing by Subject "Chemical Engineering and Built Environment"

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    Pentlandite-pyroxene and pentlandite-feldspar interactions and their effect on separation by flotation
    (2003) Malysiak, Vratislav; O'Connor, Cyril
    The present study has focused on exploring the extent to which metal ion activation occurs and influences flotation and how this can be managed so as to increase the separation of pentlandite from pyroxene and feldspar. The aim was to minimise the percentage pyroxene and feldspar reporting to the concentrate and simultaneously maximise the pentlandite recovery. The possible chemical reactions taking place on surfaces of synthetic pentlandite, natural pyroxene and feldspar were investigated at pH 4, 6 and 9 in di-sodium tetra borate solution and in synthetic process water in the case of zeta potential determinations, microflotation and ToF-SIMS (time of flight secondary ion mass spectrometry) analyses and in synthetic process water in the case of batch flotation tests.
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    Surface characterisation and flotation behaviour of the platinum and palladium arsenide, telluride and sulphide mineral species
    (2007) Shackleton, Natalie Jean; O'Connor, Cyril
    The Platreef is located in the northern limb of the Bushveld Complex of South Africa. This reef consists of a complex assemblage of rock types, with pyroxenites, serpentinites and calcsilicates being the most abundant. The predominant PGMs are the tellurides, arsenides, alloys and sulphides. The Pt and Pd tellurides contribute between 20-45% of the PGMs present in the Platreef ore followed by the alloys (26%), arsenides (21%) and sulphides (19%). Flotation is used in the processing of the Platreef ore to separate the siliceous gangue from the platinum group minerals (PGM) and base metal sulphides. The PGE arsenide and telluride minerals are considered to be slow floating when compared to other PGMs as there is evidence of them reporting to the tailings.This thesis aimed to investigate the flotation behaviour of these minerals and presents results which characterise the surface properties of synthetic cooperite (PtS), vysotskite (PdS), sperrylite (PtAS2), palladoarsenide (Pd2As), moncheite (PtPd(BiTe)2 and PtTe2) and merenskyite (PdPt(BiTe)2 and PdTe2) and attempts to relate the flotation behaviour of the various minerals to these characteristics.