Kinetics of electrochemical corrosion of chalcopyrite in presence of bacteria
(Department of Mineral Engineering, Central South University of Technology, Chang.sha 410083,P．R. China)
Abstract: Kinetic of electrochemical corrosion of chalcopyrite electrode, in both absence and presence of bacteria (Thiobacillus ferrooxidans) in acid solution, was studied using various electrochemical measurement methods. The results showed that in uninoculated acid solution the corrosion potential was 0.255 V (vs SCE), but in incoculated solution it was up to 0.308 V, and the corrosion current density was from 0.52 μA·cm-2 up to 0.64 μA·cm-2 , the corrosion rate of chalcopyrite is obviously improved. This showed that Thiobacillus ferrrooxidans in the solution enhanced dissolution of chalcopyrite. The anodic Tafel slope of chalcopyrite electrode was all about 0.6 V both in uninoculated and inoculated solution, but the cathodic Tafel slope is increased from 23.96 mV to 33.60 mV. It was shown that the presence of bacteria in the system had much effect on the cathodic polarization than on the anodic polarization. The polarization resistance R p was reduced from 19.41 kΩ in uninoculated solution to 15.91 kΩ in inoculated solution.
Key words: electrochemical corrosion； chalcopyrite electrode； Thiobacillus ferrooxiadans