M.Tech. / Recent studies have explored the capabilities of sulphur dioxide (SO2), a reducing agent that shows great potential to enhance the leaching efficiency of cobalt from mixed Co-Cu oxidized ores. The research study reported in this dissertation was conducted to further explore the efficacy of SO2 as a suitable reagent to improve the cobalt yield in solution from mixed Co-Cu oxidised ores. Four mixed Co-Cu oxidised ores were used in this study; namely, high cobalt ore (34% Co), low cobalt ore with mica (4% Co), low cobalt ore without mica (3% Co) and high copper ore (0.5% Co). The mechanistic leaching pathways of cobalt from these ores with and without SO2 were investigated and monitored using Ultra-Violet/Visible spectroscopy. Mineralogical studies of these ores was carried out by X - ray diffraction (XRD), X - ray fluorescence (XRF) and flame atomic absorption spectroscopy (AAS). Microwave processing of these ores prior to leaching experiments was also investigated. The experimental work was carried out on a laboratory scale and highlights of results obtained are summarized as follows: Although not much information pertaining to Co2+ bearing minerals in mixed Co-Cu oxidised ores was derived from XRD results, two forms of heterogenite minerals (CoOOH-2H and CoOOH-3R), which bear cobalt as Co3+ were noted in the low cobalt ores. High percentage cobalt dissolutions (85% to 95%) were achieved when leaching mixed Co-Cu oxidised ores in the presence of SO2. UV/Visible spectroscopy confirmed concentrations of Co3+ and Co2+ before and after SO2 treatment of mixed Co-Cu oxidised ores. Percentage cobalt dissolutions improved by 10% to 20% in microwave irradiated mixed Co-Cu oxidised ores The presence of iron and copper in leach solutions can limit the dissolution of cobalt from mixed Co-Cu oxidised ores to a certain extent.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:8393 |
| Date | 19 May 2009 |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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