Electrochemistry and flotation of enargite and chalcopyrite

In order to understand the selective flotation of enargite and chalcopyrite, their electrochemical behaviors in buffer solutions have been investigated using open circuit potential measurements, anodic and cyclic voltammetry in varied solution pH, scan direction, scan range, scan rate, dissolved O 2, collectors and depressants. Voltammetric, ultraviolet techniques and contact angle measurements were used to investigate the wettability of enargite and chalcopyrite as well as the oxidation of xanthate and the reduction of dixanthogen on the enargite and chalcopyrite surfaces. Selective flotation of enargite from chalcopyrite was conducted in a solution with and without a collector.; The results indicated that the potential range in which enargite exhibited the surface passivation was from -0.9 V to + 0.83 V vs. SCE. Enargite was most stable in neutral and alkaline solutions at a potential of around -0.2 V vs. SCE. The main oxidation products on the enargite surface in an alkaline solution were Cu(OH)2 when the potential was in the range of -0.2 to +0.33 V vs. SCE and Cu(OH)2 + So when the potential was higher than +0.52 V vs. SCE.; The potential range in which chalcopyrite exhibited the surface passivation was from -0.9 V to + 0.60 V vs. SCE. Chalcopyrite was most stable in neutral and weak acidic solutions around a potential of -0.2 V vs. SCE. The main oxidation products on the chalcopyrite surface in an alkaline solution were So and Fe(OH)2 when the potential was in the range of -0.2 to +0.1 V vs. SCE and Fe(OH)3 when the potential applied was higher than +0.2 V vs. SCE. The hydrophobic film on both of the enargite and chalcopyrite surfaces in a 7 x 10-4 M PAX solution at pH 10 was dixanthogen which was stable in the potential range of -0.6 V to +0.8 V vs. SCE. The floatable potential range of enargite was from -0.1 V to +0.6 V vs. SCE in a 7 x 10 -5 M PAX solution at pH 10 while the floatable potential range of chalcopyrite was from -0.1 V to +0.2 V vs. SCE under the same conditions. The separation of enargite from chalcopyrite could be achieved by electrochemical control.