Fundamental study of pyrite flotation using eco-friendly surfactin as collector

The drive towards cost-effective and environmentally friendly reagents has led to a significant increase in investigations into microorganisms and metabolites as potential collectors in froth flotation. The primary goal of this study was to develop a fundamental understanding of the interaction between surfactin, a cyclic lipopeptide biosurfactant which shows excellent surface activity even at very low concentrations, and pyrite. Surfactin adsorption on pyrite was confirmed through zeta potential and FTIR analysis and indicated a greater interaction in the neutral and alkaline pH ranges, signifying that ionisation of the surfactin carboxylic groups plays a significant role in adsorption. The attachment mechanism of surfactin onto the surface of pyrite was potentially chemisorption to either Fe-hydroxide sites or interaction of the amide groups with sulphur on the pyrite surface. Surfactin demonstrated a cleaning effect on pyrite (removal of hydrophilic species), which may contribute to increased hydrophobicity on the mineral and showed collecting abilities for pyrite at most operating conditions. Generally, surfactin performance was observed to be more effective in the alkaline pH range.