Microbial processing of apatite rich low grade Indian uranium ore in bioreactor

Bioreactor leaching using enriched culture of Acidithiobacillus ferrooxidans and Leptosprillium ferrooxidans was investigated for the apatite rich Indian (Narwapahar) uranium ore. Bioreactor leaching of Narwapahar ore of <45 μm size at pH 2.0 and 10% (w/v) PD using 10% (v/v) inoculum of the bacterium at 35 °C (A. ferrooxidans) and 40 °C (L. ferrooxidans), solubilised 57% and 63% uranium in 5 days, respectively; the ESCE values being 561 and 588 mV. Leaching kinetics improved so much so that ∼83% uranium was recovered in just 10 h with 10% inoculum of A. ferrooxidans containing biogenic Fe3+; at 20% PD uranium recovery rose to 87%. Role of temperature (25–40 °C) was noticed with 90.3% uranium bioleaching in 10 h at 40 °C with L. ferrooxidans as against 77% leaching with A. ferrooxidans at pH 2.0, 40 °C and 20% (w/v) PD.