An investigation on pyrite floatability using stable micro-nanobubbleassisted flotation

This study critically examines the impact of micro-nanobubble (MNB)-assisted flotation on pyrite recovery in bulk ore, and clarifies the intricate relationship between pyrite and its associated ore. The physicochemical properties of MNBs and the interaction mechanisms between xanthate collector and pure pyrite mineral were evaluated using advanced analytical techniques, including Dynamic Light Scattering (DLS), Field-Emission Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (FESEM-EDX), and Ultraviolet-Visible Spectroscopy (UV-Vis), in the absence and the presence of MNBs. MNBs were created through hydrodynamic cavitation, and their characteristics revealed a size increase from 600 nm to 3 mu m over 25 days. Notably, the zeta potential measurements indicated an increase from-2.5 to 0 mV at a constant pH of 8, correlating with the geometric mean size of MNBs coarsening from 600 nm to 2-3 mu m. The FESEM and EDS analyses disclosed that ultrasonic treatment effectively dispersed ultrafine surface coatings on pyrite particles, increasing iron and sulfur purity by 8% and 6%, respectively, and significantly reducing surface oxygen by 53%. Micro-flotation and batch rougher kinetic flotation experiments were conducted with and without MNBs, leading to a 7% and 8% improvement in recovery for pyrite mono-minerals (-105+53 mu m) and its ore (d(80) =150 mu m), respectively. The sorption behavior of sodium isopropyl xanthate (SIPX) collector on the particle surface was also investigated at various concentrations (ca. 10-160 mu M) in the presence and absence of stable MNBs and demonstrated that the presence of MNBs resulted in a 1.6-fold increase in collector absorption on the pyrite surface, confirming the findings obtained from micro-flotation. Moreover, adsorption behavior is up to 1.3 times compared to the scenario without MNBs. The adsorption process was controlled by a pseudo-second-order model, indicating a chemical sorption mechanism.