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

• Flotation of bastnaesite suffers from high reagent consumption and complex stages of high-temperature conditioning due to the similar surface characteristics of bastnaesite and associated gangue minerals, including calcite. This research seeks to develop a sustainable flotation reagent scheme for the optimal recovery of bastnaesite using organic acids as depressants and sodium oleate as the collector. • As such, systematic flotation experiments were conducted to investigate the impact of pH, collector dosage, and organic acids concentration on the flotation performance of bastnaesite when calcite exists as the primary gangue mineral. The selective flotation of bastnaesite from calcite has been studied by micro-flotation, zeta potential, adsorption density measurements, and XPS characterization using organic acids, namely lactic acid and succinic acid, as depressants and NaOL as the collector. • The results of flotation tests indicated that the addition of lactic and succinic acids dramatically reduced the recovery of calcite while remaining impotent to the recovery of bastnaesite. The data demonstrated that both organic acids are selective depressants for calcite. At the optimal level of pH, sodium oleate and organic acid dosages, the recovery of calcite was reduced to below 10% and 20%, where bastnaesite recovery remained above 85% and 90% when succinic acid and lactic acid were the respective depressants. 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. [ABSTRACT FROM AUTHOR]