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UV/Vis spectroscopy was used to determine qualitatively and quantitatively Cu 2+ , Co 2+ , Co 3+ and Fe 3+ in oxidised Cu-Co ore leachates. The mineralogical and chemical characteristics of the three oxidised Cu-Co ore samples considered were determined using FT-IR, XRD, SEM-EDS and XRF. The results showed that Cu and Co in the samples were in the form of carrollite (Co 2 CuS 4 ), malachite (Cu 2 CO 3 (OH) 2 and heterogenite (CoO(OH)). The samples contained (2.73%Cu and 0.19%Co), (2.82%Cu and 0.07%Co) and (0.03%Cu and 0.05%Co), respectively. Gangues were mainly constituted of quartz, goethite and hematite. The UV/Vis results indicated that the wavelengths of absorbance of the metal ions in dilute EDTA aqueous solution (pH≈3.5)were Fe 3+ (293 nm), Cu 2+ (821 nm), Co 3+ (344 nm) and Co 2+ (512 nm). The molar concentrations of the metal ions obtained using the UV/vis method compared well with results obtained using the AAS method. UV/vis spectroscopy was also used to monitor the conversion of Co 3+ into Co 2+ using different reducing agents. The results showed that the molar concentration of Co 2+ in the aqueous solutions increased with addition of reducing agents, of about 80.95% (copper foil), 61.22% (ferrous sulphate) and 20.35% (sodium sulphite) respectively.2

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