Acidophilic Iron- and Sulfur-Oxidizing Bacteria, , Drives Alkaline pH Neutralization and Mineral Weathering in Fe Ore Tailings.

The neutralization of strongly alkaline pH conditions and acceleration of mineral weathering in alkaline Fe ore tailings have been identified as key prerequisites for eco-engineering tailings-soil formation for sustainable mine site rehabilitation. has great potential in neutralizing alkaline pH and accelerating primary mineral weathering in the tailings but little information is available. This study aimed to investigate the colonization of in alkaline Fe ore tailings and its role in elemental sulfur (S) oxidation, tailings neutralization, and Fe-bearing mineral weathering through a microcosm experiment. The effects of biological S oxidation on the weathering of alkaline Fe ore tailings were examined via various microspectroscopic analyses. It is found that (1) the inoculum combined with the S amendment rapidly neutralized the alkaline Fe ore tailings; (2) activities induced Fe-bearing primary mineral (e.g., biotite) weathering and secondary mineral (e.g., ferrihydrite and jarosite) formation; and (3) the association between bacterial cells and tailings minerals were likely facilitated by extracellular polymeric substances (EPS). The behavior and biogeochemical functionality of in the tailings provide a fundamental basis for developing microbial-based technologies toward eco-engineering soil formation in Fe ore tailings.