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Résumé :
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Various collectors were compared in the selective flotation of copper-zinc ore by using isopropyl ethylthionocarbamate (Z-200), buthl xanthate, ammonium dibutyl dithiophosphate, and mercapto benzothiazole (MBT). The latter showed effective selectivity in the flotation of chalcopyrite and marmatite and was selected for a detailed study by using cyclic voltammetry and Tafel. The results of microflotation pointed out that the flotation of marmatite was significantly affected by CuSO4 activation. At weakly alkaline pH, marmatite activated by Cu2+ is dependent on Cu2+ concentration shown in electrochemical tests, and the activation products were Cu2S and CuS. The increasing addition of Cu2+ may remove the hydroxide and S0, resulting in considerable activation. The corrosion of marmatite is accelerated with the addition of CuSO4. Mechanisms are suggested for the selectivity of chalcopyrite/marmatite by MBT: the hydrophilic hydroxides (Zn(OH)2 and Fe(OH)3) are formed on the marmatite surface, which renders the marmatite surface hydrophilic and hampers the reaction between MBT and marmatite-activated products, while the hydrophobic compounds (MBT)2 and Cu(MBT)2 formed on the chalcopyrite surface improve the flotability of chalcopyrite.
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