Biodestruction and deferritisation of quartz sands by Bacillus species.

Quartz sand containing mineral impurities, from Vysny Petrovec in Slovakia, was biologically leached for 3 months by strains of Bacillus bacteria to determine the reduction of Fe(III)-oxyhydroxides and the effect of particle size on the extent of Fe removal. Bioleaching removed visible Fe-bearing minerals that coated the quartz grains. Elements were dissolved from silicate minerals and poorly crystalline Fe-oxides that sealed siderite nodules were released from intergranular spaces to form a fine-grained fraction whose voltammetry indicated reductive dissolution of Fe3+. Chemical analysis showed a slight increase in Fe2O3 content and a decrease in FeO content. X-ray diffraction analysis showed a loss of Fe-bearing minerals and mica while transmission electron microscopy and energy-dispersive X-ray analysis showed nucleation of fine-grained Fe,Al silicates on the surfaces of bacteria.
Quartz sand containing mineral impurities, from Vysny Petrovec in Slovakia, was biologically leached for 3 months by strains of Bacillus bacteria to determine the reduction of Fe(III)-oxyhydroxides and the effect of particle size on the extent of Fe removal. Bioleaching removed visible Fe-bearing minerals that coated the quartz grains. Elements were dissolved from silicate minerals and poorly crystalline Fe-oxides that sealed siderite nodules were released from intergranular spaces to form a fine-grained fraction whose voltammetry indicated reductive dissolution of Fe3+. Chemical analysis showed a slight increase in Fe2O3 content and a decrease in FeO content. X-ray diffraction analysis showed a loss of Fe-bearing minerals and mica while transmission electron microscopy and energy-dispersive X-ray analysis showed nucleation of fine-grained Fe,Al silicates on the surfaces of bacteria.