Metal Ion Release in Bastnaesite Flotation System and Implications for Flotation

Ca2+, Mg2+, Sr2+ and Fe3+ were found to be commonly released into bastnaesite flotation pulp from minerals with relatively high concentrations. The influence and corresponding mechanism of Ca2+, Mg2+, Sr2+, Fe3+ and Al3+, on bastnaesite flotation, have been studied by micro flotation tests, induction time measurements, adsorption measurements and solution chemistry analysis. It was found that all aforementioned metal ions depressed bastnaesite flotation. The order of depression ability was Fe3+ > Al3+ > Mg2+ > Sr2+ > Ca2+ and the depression ability changed along with pH. The depression was mainly attributed to the adsorption of metals ions, which hindered collector adsorption. The species diagrams of metal ions changed along with pH, consequently changing the adsorption of metal ions on mineral surfaces, and therefore leading to different influences on flotation.