Abstract: In order to study the effect of quaternary ammonium collectors on the reverse flotation of bauxite， the effects of cetyl trimethylammonium bromide （CTAB） on the flotation recovery of diasphalite and kaolinite were investigated using dodecyl amine （DDA） as reference collector.The mechanism of action was systematically analyzed by FTIR analysis， Zeta potential detection， adsorption capacity measurement and molecular dynamics simulation.The flotation test results showed that CTAB showed the better flotation separation effect compared with DDA. Under the condition of pH of 4 and CTAB concentration of 2×10-4 mol/L， the flotation recovery rate difference of diaspore and kaolinite in the flotation test of pure minerals is up to 51.70 percentage.A concentrate with Al2O3 grade of 71.73%， recovery rate of 71.26% and SiO2 contents of 9.43% was obtained by artificial ore mixing test. The Al/Si ratio reached to 7.60.The results of mechanism analysis showed that the collector CTAB adsorbs on both diaspore and kaolinite， and the adsorption amount on the surface of kaolinite is greater than that on the surface of diaspore， which both are physical adsorption.The results of molecular dynamics simulation showed that the total interaction energy between collector CTAB and kaolinite is 2.29 times that of collector CTAB on diaspore. Therefore， CTAB molecules are adsorbed on the surface of kaolinite firstly， which has high selectivity and is beneficial to reverse flotation.

Key words: reverse flotation, quaternary ammonium salt, diaspore, kaolinite