Enhanced flotation separation of fluorite and calcite using novel collector: Experimental and theoretical Insights

The surface characteristics of fluorite and calcite exhibit a close analogy, posing a formidable challenge to flotation separation. Hence, the development of a highly efficient reagent for fluorite holds paramount significance and value in addressing the challenging separation of fluorite and calcium-bearing minerals. In this study, a novel collector, decyl-bishydroxamic acid (DCBHA), has been ingeniously designed and synthesized to effectively separate fluorite and calcite. Conducting micro-flotation experiments encompassing single minerals and artificially mixed minerals, we systematically investigate the flotation performance of DCBHA in fluorite flotation systems. It was observed that DCBHA exhibited commendable collective and selective ability compared to BHA and OHA, yielded a concentrate grade of up to 70.99% with a recovery of 76.24%. at optimal conditions. The zeta potential, AFM, FTIR and XPS examinations indicated the selective chemical adsorption of DCBHA on the metallic sites of the fluorite surface. The incorporation of a second hydroxamic acid group concurrently enhanced the collecting capacity and selectivity of the reagent. The mechanism of interaction between the novel collector DCBHA and mineral surfaces was investigated through Density Functional Theory (DFT), revealing that DCBHA exhibited a "bidentate" adsorption pattern upon losing a proton H, forming bonds with the mineral surface. Furthermore, the adsorption affinity of DCBHA to fluorite surpassed that to calcite, providing advantageous support for experimental findings.