A Sulfur K-Edge XANES and Raman Study on the Effect of Chloride Ion on Bacterial and Chemical Leaching of Chalcopyrite at 25 °C
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In the present study, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray absorption near edge structure (XANES) spectroscopy, and Raman spectroscopy were used to investigate the effect of chloride ions on chalcopyrite bioleaching and chemical leaching at 25 °C. The leaching results show that the addition of chloride ions suppressed the dissolution of chalcopyrite in both chemical and bacterial leaching. In chemical leaching, the solution redox potential in the experiment without Cl− stayed in a range more suitable for chalcopyrite dissolution compared with experiments with Cl−. In bioleaching, the bacteria activity was suppressed by Cl− leading to low dissolution rates of Cu. Surface morphology and chemical speciation studies confirmed the formation of potassium jarosite on the surface of the chalcopyrite leach residues. In addition, S K-edge XANES indicated the formation of trace amount of elemental sulfur and covellite on the mineral surfaces.
KeywordsChloride ion Chalcopyrite XANES Surface species
The authors appreciate the help of Dr. Matthew Glenn on scientific and technical assistance during SEM measurements. The authors appreciate the help from the RMIT Separation Science and Mass Spectrometry Facility. XANES measurements were undertaken at the Beijing Synchrotron Radiation Facility (BSRF).
The authors appreciate funding from the Australian Research Council grant (ARC LP160101760). And we appreciate the support provided by the beamline scientists and staff of the BSRF. We acknowledge travel funding provided by the International Synchrotron Access Program (ISAP) managed by the Australian Synchrotron, part of ANSTO, and funded by the Australian Government.
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