Flotation techniques for separation of diaspore from bauxite using Gemini collector and starch depressant

The floatability of diaspore and three kinds of silicate minerals, including kaolinite, illite and pyrophyllite, by a cationic Gemini surfactant as collector and starch as depressant was investigated as function of reagents concentration and pulp pH. Further studies of artificially mixed minerals and bauxite ore were also detailedly conducted. At last, the pre-desliming reverse flotation separation process was adopted. It can be concluded that the combinational use of a Gemini cationic collector and the starch depressant is effective. The concentrates with Al2O3 to SiO2 mass ratio of 9.66 and the recovery of Al2O3 of 71.73% are obtained from natural bauxite ore (A/S=5.70) at pH value of around 10.