Electrochemical investigations of various sulphides, xanthates systems and sulphides, iron, xanthates systems

An electrochemical study was carried out on various electrodes of sphalerite, pyrite, pyrrhotite, chalcopyrite and galena in deoxygenated and air-saturated solutions at different concentrations of potassium ethyl xanthate (KEtX), i.e. 0 M, 10⁻⁵ M, 3 x 10⁻⁵M, 10⁻⁴ M, 3 x 10⁻⁴ M, 10⁻⁴M, 10⁻³ M and pH (1 to 12) at 25°C ± 1°C. The effect of galvanic contact between various sulphides and metallic iron on various electrochemical characteristics of the galvanic couple was also investigated. Following a pseudo Nernst relationship, the rest potentials of various electrode systems became more negative with the higher concentration of KEtX. The electrochemical series of the sulphide minerals investigated, in potassium ethyl xanthate solution, in the order of their nobility, were sphalerite, pyrite, pyrrhotite, chalcopyrite and galena. All sulphide-xanthate-air systems displayed more noble rest potentials than the redox potential of potassium ethyl xanthate at natural pH; however, the rest potentials of most sulphides except for sphalerite became more negative than the redox potential of potassium ethyl xanthate at a pH of 9. Solution purging with air caused the rest potentials of all sulphides investigated to shift in the noble direction because of the oxygen reduction. Various sulphide-iron galvanic couples acquired mixed potentials which lay between the rest potentials of sulphides and iron. The exact value of the mixed potential of the particular electrode system was varied depending on the relative surface area of the two electrodes in galvanic contact. The experimental potential-pH diagrams were constructed for the minerals and metallic iron in the solutions of 0 M and 10~5 M of potassium ethyl xanthate.Applied Science, Faculty ofMining Engineering, Keevil Institute ofGraduat