Abstract: Diaspore from Yunnan is one kind of high silicon and aluminium while low w (Al₂O₃)/ w (SiO₂) bauxite.Studied the technological conditions on the reverse flotation process in increasing aluminium grade and decreasing silicon content in bauxite.The results demonstrate that at these optimal conditions of 85% -0.074 mm grinding size, pH=5.5, 150 g/t of combination collector GE-601 and E3 with a mass ration of 2∶1, 600 g/t of OP as depressor, after once roughing, once cleaning and three times scavengings, middlings order to return could get the Al₂O₃ grade of 67.65% and 67.52%, and recovery of 82.04% and 81.77% with a w (Al₂O₃)/w (SiO₂) of 10.72 and 10.58 when reaction at room temperature and 8 ℃, separately.These results indicate that our combination collector works better in low temperature.

Key words: Bauxite, Reverse flotation, Combination collector