Study on the adsorption selectivity of a novel fatty acid collector on apatite, dolomite, and calcite surfaces for improved flotation

Despite being a common choice for apatite flotation, oleic acid collector suffers from deficient selectivity. To resolve this constraint, this study introduces a novel fatty acid collector, α-sulfonate group mixed acid (α-SMA), a blend of C16 to C18 fatty acids containing an α-sulfonate group, as a replacement for oleic acid. This study compares the selectivities of α-SMA and oleic acid collectors through flotation experiments. The adsorption capacities of α-SMA on apatite, dolomite, and calcite were quantified using zeta potential tests and total organic carbon (TOC) analysis. X-ray photoelectron spectroscopy and first-principles calculations were used to characterize the adsorption intensities and configurations of α-SMA on mineral surfaces. The results demonstrate that α-SMA surpasses oleic acid in selectivity during apatite direct flotation. Specifically, the flotation recoveries of apatite can be above 80% higher than those of dolomite and calcite. This enhanced selectivity stems from the higher adsorption quantities of α-SMA on apatite relative to dolomite and calcite. TOC analysis indicates that, under specific conditions, α-SMA adsorbs on apatite at nearly twice the amounts observed on dolomite and calcite. Optimization of adsorption configurations reveals that α-SMA adopts a parallel adsorption orientation on dolomite and calcite surfaces, where its C chain aligns nearly parallel to the mineral surfaces. This parallel configuration explains the weak collecting abilities of α-SMA for these two minerals. This study highlights the promising potential of α-SMA collector in apatite flotation, providing a foundation for its industrial application. It also underscores the significant research and development value of collectors with multiple polar groups.