Pyrite and pyrrhotite open circuit potentials study: Effects on flotation

In this research, effects of chloride & sulfate ions and pH changes on the open circuit potentials of pyrite, pyrrhotite and steel and also their reduction-oxidation processes were studied. These potentials were measured at different pH values in 3 electrolytes: distilled water, sodium chloride solution and sodium sulfate solution. A pair of electrodes including reference and operative electrodes was used for measurement and control of potentials. The results showed that with pH increasing, pyrite and pyrrhotite open circuit potentials decrease whereas under the same conditions the mentioned potential for steel rises. It was also observed that use of sodium chloride and sodium sulfate solutions as electrolyte decreases the open circuit potentials, because the presence of chloride and sulfate ions speeds up the oxidation-reduction process. Furthermore, the effect of the mentioned parameters on galvanic interactions between minerals and grinding media in grinding circuits, as well as galvanic interactions between the minerals in flotation process, mineral floatability and their collector adsorption have been discussed. (C) 2011 Elsevier Ltd. All rights reserved.