Evaluation of lactic and succinic acids as green depressants for selective flotation separation of bastnaesite from calcite

Bastnaesite is a primary natural source of light rare earth elements. Adequate flotation of bastnaesite, as a fluoro carbonate mineral, in the presence of various Ca-containing gangue minerals, such as calcite, is complex due to similar surface characteristics. This study aimed to develop an environmentally benign flotation reagent scheme using organic acids to enhance bastnaesite flotation while selectively depressing calcite. Systematic flotation, zeta potential, adsorption density, and X-ray photoelectron spectroscopy analyses were carried out using lactic acid (LA) and succinic acid (SA) as depressants and sodium oleate as a collector. The results of flotation and surface chemistry analyses demonstrated that organic acids preferentially adsorbed on the calcite surface, significantly reducing calcite recovery to below 20% and 10% when using lactic acid and succinic acid, respectively. The collective findings of this study demonstrate the tremendous potential of organic acids to be used as effective calcite depressants in bastnaesite flotation system.