Bioleaching of Vanadium-Bearing Shale by Acidithiobacillus Ferrooxidans Using Pyrite as an Energy Resource

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Abstract Bioleaching of vanadium (V)-bearing shale by Acidithiobacillus ferrooxidans using ferrous ions as the sole energy source rapidly decreases the V leaching efficiency. To reduce the formation of jarosite and improve leaching efficiency, we examined the bioleaching process of V-bearing shale-adapted A. ferrooxidans grown with pyrite, providing insight into the optimal conditions for V extraction and bioleaching. Experiments were conducted by varying the pulp density, grinding size, initial pH, initial cell concentration, and pyrite concentration. Under optimum process conditions (40 g/L pulp density, sample particle size of less than −400 mesh accounting for 56.95%, and 12 g/L initial pyrite at pH 2.00), V leaching rates were increased by 15%–25% compared to sterile controls. Moreover, this study describes the balance between V leaching from V-bearing shale by A. ferrooxidans, the synergistic effect of its oxidation products (Fe3+ and H+), and V loss by coprecipitation and adsorption of jarosite. Our findings indicate that using pyrite rather than ferrous ions as the sole energy source can reduce the influence of jarosite.