Co-adsorption of NaOL/SHA composite collectors on cassiterite surfaces and its effect on surface hydrophobicity and floatability

A binary collector system containing sodium oleate/salicylhydroxamic acid (NaOL/SHA) was optimized to improve the floatability of cassiterite at low concentrations. The results of the microflotation experiments demonstrated that the binary mixture performed better than the single collector. At the optimum pH of 8.0 and a total collector concentration of only 5 x 10-5 mol/L, the flotation recovery of cassiterite in the presence of the NaOL:SHA (1:2) mixture was above 90 %. The synergism between NaOL and SHA was rationalized by studying the changes at the solid-liquid interface based on zeta potential measurements, collector adsorption quantifi-cation, surface tension analysis, and X-ray photoelectron spectroscopy. Density functional theory calculations confirmed that the co-adsorption of the two collectors resulted in strong O-Sn chemical bonds with the cassiterite surface.