The significance of collector colloid adsorption phenomena in the fluorite/oleate flotation system as revealed by FTIR/IRS and solution chemistry analysis

Previous spectroscopic studies of the fluorite/oleate flotation system have shown that under certain conditions calcium dioleate is formed at or transported to the fluorite surface, leading to multilayer formation in the, so-called, surface precipitation region of the adsorption isotherm. Most studies show that the adsorbed calcium dioleate compound becomes significant at equilibrium oleate concentrations of between 4 X 10(-6) M and 4 X 10(-5) M, yet little explanation regarding the nature of this adsorption phenomenon is provided. In this study both ex-situ and in-situ FTIR/IRS experiments have been utilized in connection with a thermodynamic solution chemistry analysis to better understand the oleate adsorption mechanism as well as the factors which control precipitate formation and adsorption. Results show that control of calcium ion concentration and pH in solution are crucial in determining both the form and quantity of the adsorbate. Also, results suggest that the predominant mechanism of calcium dioleate adsorption is formation of calcium dioleate in solution, followed by transportation to the surface rather than nucleation and growth at the surface as a surface precipitate.