Investigation for Selective Flotation of Pyrite-Chalcopyrite Based on the Oxidation and Adhesion Potentials of Marine Fe-Oxidizing Bacteria in Seawater

Abstract

Seawater is expected to be directly used as a process water for the copper ores flotation plants, where pyrite is depressed under alkaline condition (>10). However, excess alkaline agents could be consumed due to the buffering effect of seawater salts, and introducing seawater to the plant causes the generation of hydrophilic particles under the pH condition, resulting in a decrease in the recovery of valuable minerals. This study investigated the potential effect of hydrophilization on pyrite and chalcopyrite surface by promoting oxidative dissolution and bacterial adhesion using two strains of marine iron-oxidizing bacteria (Thalassospira sp., Mariprofundus sp.). We observed selective adhesion of hydrophilic bacterial cell on pyrite surface but little difference in the chemical properties on the pyrite surface by bacterial reaction. Therefore, the hydrophilic/hydrophobic property of marine iron-oxidizing bacterial cell is a significant controlling factor of flotation behavior in seawater.