Surface complexation model theory application in NaOL and CTAB collector adsorption differences of diaspore and kaolinite flotation

Abstract

Although the relevant direct and revers flotation mechanism has been discussed a lot in diaspore and kaolinite separation, the quantitative analysis of surface-active sites and their reaction descriptions during flotation have not been reported yet. In this study, the hydration and collector adsorption reactions of anionic sodium oleate (NaOL) and cationic hexadecyl trimethyl ammonium bromide (CTAB) onto diaspore and kaolinite were quantized. Surface complexation model (SCM) was referred to obtain intrinsic reaction equilibrium constants. It can be found that for NaOL adsorption, the equilibrium constant of diaspore (1013.55) was obviously bigger than that of kaolinite (1011.76 and 1010.35 for ≡AlOH and ≡SiOH, respectively), corresponding to direct flotation of bauxite. While the interaction (103.90 for ≡XNR) between the permanent negatively charged site ≡X− and CTAB was much stronger than other sites. Besides, the single adsorbed amount in mixed minerals were successfully predicted at ratios of 1:2, 1:1 and 2:1. Finally, the fitted potential curves were also acceptable to zeta potential tests. These conclusions from SCM calculation can provide strong supports for collector adsorption differences and then help for separation much more efficiently and economically through saving preliminary exploration cost.