In copper mineral processing, pyrite coexisting with copper sulfide minerals like chalcopyrite is separated by flotation as tailings and its oxidation in tailing dams causes the formation of acid mine drainage. This paper proposes carrier-microencapsulation (CME) as a new method for suppressing pyrite flotability, as well as its oxidation. In this method, an organic carrier combined with Ti is used to form a thin TiO_2 layer on pyrite, which gives a hydrophilic property and acts as a protective coating against oxidation. To form the coating, a ground pyrite sample was treated with Ti-catechol complex solution under various conditions. Bubble pick-up experiments and flotation experiments showed that the treatment of pyrite with Ti-catechol complex changed the hydrophobic nature of pyrite into hydrophilic even in the presence of xanthate as a flotation collector. Oxidation testing of the CME-treated pyrite by 0.G2 kmol m~(-3) HNO_3 showed that Fe release was suppressed by the CME treatment with respect to the control. This is assumed to be due to the formation of TiO_2 coating on the pyrite surface. The effect of CME treatment on chalcopyrite wettability is also discussed.
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