The Impact of Backwater Iron Ions on Bauxite Flotation

The effect of iron ions in backwater on the flotation of diaspore bauxite was investigated by ICP measurement, micro-flotation tests, zeta potential measurements and solution chemistry analyses. The concentration of iron ions in backwater was 1 × 10−5 mol/L measured by ICP. The micro-flotation results indicated that iron ions activated the flotation of diaspore at pH 4 and depressed the flotation of diaspore at pH 7, while activated the flotation of kaolinite at pH 4–9. In particular, the flotation of kaolinite had a great increase in the presence of iron ions at pH 8–9, the pH value usually used in industry flotation. The iron ions were adsorbed on the mineral surface mainly in the formation of Fe(OH)3(s). It changed the zeta potential of minerals and modified the surface properties of minerals, then transformed the interaction between minerals and collectors, and finally affected the flotation of diaspore and kaolinite. The study might have some reference significance to the industry flotation.