flotation, and the species responsible for collectorless flota-Chalcopyrite in contact with water is thermodynamically unstation (1-7).
ble in the presence of oxygen. Oxidation of chalcopyrite may take Literature reports have dealt with the issue whether or not place due to various factors, e.g., geological environment, mining/ oxidation is deleterious to flotation. Data on the electrochemcomminution, and storage. In this work oxidation of chalcopyrite istry of chalcopyrite often supplemented by XPS studies has been investigated through interfacial electrokinetics. The charsuggest the oxidation mechanism to be quite complex. It is acteristics of samples obtained from different geological locations well known that oxidation of sulfide minerals is, in general, as well as the effects of ageing and laboratory oxidation have been a complex process and includes several oxidation/reduction, delineated. Variation of the solid-liquid ratio was found to have complexation and hydrolysis reactions (8). Since the solida significant effect on the zeta-potential characteristics of chalcopyrite. The role of constituent metal ions, namely copper and iron, liquid interface in a mineral suspension is strongly influhas been studied in the absence and presence of externally added enced by the concentration of constituent ions in solution, metal ions. The results indicated that the ratio of Cu/Fe on the electrokinetic technique is an excellent in situ tool for studysurface of oxidized chalcopyrite determines the Stern layer potening various reactions at the mineral surface. This technique tial and under appropriate solution chemistry conditions influhas been successfully employed for studying oxide minerals ences charge reversals. The mineral surfaces, thus, could be either as well as sulfide minerals like galena, sphalerite, and pyrite. copper-rich or iron-rich as reflected by a shift in pH iep (s). The Healy and Moignard (9) have presented an excellent review observed charge reversals have been explained on the basis of a on the electrokinetics of sulfide minerals. However, the inmodel proposed by James and Healy.