Sulfur speciation on the surface of chalcopyrite leached by Acidianus manzaensis

Sulfur speciation on the surface of chalcopyrite leached by extremely thermophilic Acidianus manzaensis was investigated by employing scanning electron microscopy (SEM), X-ray diffraction (XRD) and sulfur K-edge X-ray absorption near edge structure spectroscopy (XANES). SEM micrographs showed that the cells were attached to the surface of chalcopyrite and the mineral surface was covered with many floccules after 20-day bioleaching. XRD spectra indicated that the leach residue was mainly composed of chalcopyrite and jarosite, whilst the sulfur K-edge spectra indicated that the jarosite might be the main component of the passivation layer of the chalcopyrite leached by A. manzaensis. The results of spectral graphic analysis suggested that covellite was the intermediate sulfur compound during bioleaching of chalcopyrite.