As part of a Bureau of Mines investigation of the feasibility of using electrochemical potential as a control parameter in sulfide mineral flotation, the effects of copper and iron species on the response of the electrochemical potentials were examined for platinum (pt), chalcopyrite (cufes2), chalcocite (cu2s), and pyrite (fes2) electrodes. Electrode potentials were measured in copper (II) and iron (II) sulfate solutions under nitrogen, oxygen, and open-to-air conditions. In general, the potentials agreed with thermodynamic values. In the absence of oxygen, electrode potentials were ph independent in the acidic ph range but were dependent on metal ion concentration. In the alkaline ph range, electrode potentials varied with ph as a result of passivation of the electrode surface due to the formation of oxides and hydroxides. The pt and mineral electrode potentials, with the exception of cu2s in copper (II) sulfate solution, were sensitive to the presence of oxygen. Redox potential values measured in a copper-molybdenum rougher flotation circuit of an operating plant are presented. Electrode potentials measured in the plant for fes2 and cufes2 follow the equilibrium for fes2 and hydrous fe (III) oxide in the ph range 10 to 12.
Electrochem. Soc., V. 88-21, 1988, PP. 84-100