Abstract: Theoretically based on the difference in the hardness and density of diaspore and silicate mineral in bauxite, the analysis is made of where the difficulty lies in their classification and separation by conventional gravity method. It is suggested to introduce a cyclonic centrifugal field to intensify the difference in density, and the test is made on bauxite ore with A/S of 4.39 and a grind of 61.90% -0.074mm. The test results show that by increasing the feeding pressure of the hydrocyclone,the separation based on the density difference can be effectively strengthened. Increasing the apex diameter of the hydrocyclone can obtain underflow and overflow with A/S being 6.5～7.0 and 2.08 respectively. This can be an effective technical reference for the pre-desliming of low grade bauxite.

Key words: Low grade bauxite, Selective grinding, Hydrocyclone, Centrifugal field