IN SITU CHARACTERIZATION OF SULFIDE MINERALS DURING LEACHING PROCESSES

摘要

To improve the efficiency of sustainable recovery of valuable resources (such as copper, gold, uranium), advanced electrochemistry, surface chemistry and materials characterization techniques, including synchrotron X ray-absorption spectroscopy (XAS), X-Ray photoelectron spectroscopy (XPS) and in situ X-ray diffraction (XRD), have been employed to investigate the sulfide mineral during the leaching process. For example, oxidation of arsenopyrite at elevated temperature involves very complex reaction systems and the products have a considerable impact on the downstream operations of gold recovery and waste management. This process is influenced by the solution conditions and mineralogy. These studies have been performed in situ to gain a detailed understanding of the chemical reaction mechanisms operating in the leaching process. It has been demonstrated that alternating current scanning electrochemical microscopy (ac-SECM) allows for straightforward characterization of sulfide mineral samples in aqueous solution. With this technology localized electrochemical properties of the mineral surface, including surface current mapping, can be achieved. Robust chemical sensors have been developed in CSIRO for real time, in-situ monitoring key solution chemical parameters of the leaching process.