Effect of l-glycine on bioleaching of collophanite by Acidithiobacillus ferrooxidans

Scanning electron microscopy (SEM) observations of the mineral sample and leached residues showed during the process of bioleaching, brushite crystallites developed within the leached collophanite residues, which were intermixed with jarosite precipitates. These changes of mineral morphological features due to the exposure to bacteria could be also confirmed by X-ray diffraction (XRD) analyses of leached residues. It was shown by XRD and Elemental analyses of leached residues that the enhanced leaching of collophanite ores supplemented with l-glycine coincided with the declined formation of jarosite precipitates as a passivation layer on the mineral surface, due to Lower pH within the leaching culture by adding l-glycine.