Biodepression of pyrite using Acidithiobacillus ferrooxidans in seawater

The current work introduces the use of Acidithiobacillus ferrooxidans, bacteria commonly used in bioleaching, as an alternative to depress pyrite in seawater flotation. This work presents the results of biodepression, at microflotation scale, in three systems: fresh water, saline water (35 g/l of NaCl, which corresponds to the salt concentration in seawater) and seawater. It was determined that when pyrite is bio-conditioned with A. ferrooxidans before flotation, recovery of pyrite at pH 8 drops from 99% to 24% and 34% in fresh water and saline water, respectively. A similar behavior is observed when running the experiments in seawater, where recoveries drop from 97% to 36% in the presence of A. ferrooxidans in flotation at natural pH (7.8-8.2). Results show that it is possible to bio-depress pyrite with A. ferrooxidans in seawater flotation at natural pH.