Effect of surface roughness on interaction of particles in flotation

In this study, the effect of roughness of particles on flotation efficiency along with surface forces among interacting particles was investigated. Glass beads representing smooth spherical particles with a size fraction of -150+90 μm were used. The etching technique was used to produce roughness of different degrees. Microflotation of round+smooth, and its corresponding etched samples were used to evaluate the efficiency of flotation in the case of smooth and rough systems. Atomic Force Microscope (AFM) was used to reveal the interaction forces between the smooth and rough surfaces. According to the results, roughness of particles increased the flotation efficiency. Although the roughness of particles increased with the etching, excess etching time caused a decrease on the roughness and in turn in the flotation recoveries. The interaction forces between the glass beads changed from repulsion to attraction with the increasing hexadecyltrimethylammonium bromide (HTAB) concentration. Further, the increase in HTAB concentration caused a change in the reversal of interaction forces from attraction to repulsion for both smooth and rough surfaces. This change started at low HTAB concentrations for rough surfaces compared to smooth ones though the magnitude of interacting forces decreased for the rough surfaces. The extent and kinetics of HTAB adsorption was dramatically influenced by the roughness of particles that affected the interaction forces as revealed by AFM measurements, and governs the flotation efficiency of particles. These results showed that roughness of particles causes significant improvement in flotation recoveries.