In this research bioleaching of Sarcheshmeh molybdenite concentrate was evaluated using a native strain of Acidithiobacillus ferrooxidans for extraction of rhenium. The research showed that dissolution of rhenium is mainly dependent to the complete dissolution of molybdenum. This may occur due to the substitutional replacement of molybdenum by rhenium in the molybdenite lattice, (because the atomic radius of rhenium is very close to that of molybdenum). The experiments showed that precipitation of molybdenum as molybdenum oxide in the solution was possible, but it was not possible for the rhenium. Hence, this was used to separate selectively rhenium and molybdenum in the solution. Experiments were expanded to determine optimum conditions for the dissolution of molybdenum from molybdenite and precipitation of molybdenum in the solution. The effect of applying other energy sources, different pulp densities and culture media in the experiments were investigated. Applying 1% pulp density, 9K culture medium and addition of ferrous sulfate bioleaching tests showed that maximum rhenium extraction was 7.3 % while molybdenum extraction was 0.54 %.
The native strain of the Acidithiobacillus ferrooxidans was able to grow on the media that contain up to 250 mg/L molybdenum while pyrite was an additional source of energy. This caused approximately three times more molybdenum uptake than those reported in the literatures for Acidithiobacillus ferrooxidans.
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