Characterization of intermediate sulfur layer during acidic oxidation of chalcopyrite using AFM and EIS.

摘要

The utilization of Electrochemical Impedance Spectroscopy (EIS) along with Atomic Force Microscopy (AFM) is a new direction in the surface characterization of Chalcopyrite oxidation. Chalcopyrite leaching kinetics are known to decrease as leaching proceeds, mainly due to the formation of an elemental sulfur layer. The objective of the study was to characterize this passive layer at various oxidation potentials in acidic medium. AFM imaging was performed in conjunction with EIS and the surface of the sample was analyzed for grain size, roughness, peak height, sulfur growth, etc. The impedance data was fitted to an equivalent circuit and the characteristic resistance and capacitance data under working conditions were obtained. The circuit simulations reveal that the critical resistance (R