Mechanism of dispersion and aggregation in reverse flotation for bauxite

It is required to remove silicate minerals from diasporic bauxite in order to enhance the Al/Si ratio of the bauxite. Flotation, especially reverse flotation, is an effective method for removal of silicate minerals. The particulate state (aggregation/dispersion) of suspension has an evident influence on selective flotation of silicate minerals from diaspore in bauxite. The interaction force profiles between diaspore and kaolinite, illite, pyrophyllite have been calculated and the possible heter aggregation phenomena between diaspore and various silicate minerals has been discussed based on classical DLVO theory. Slime coating and heter aggregation between aluminium silicate minerals and diaspore should be avoided in order to obtain good flotation separation. It is shown by flotation tests that the use of dispersant plays an important role in improving the reverse flotation process of disaporic bauxite.