Abstract: Taking bauxite from Henan and Shanxi Province as raw material,grinding tests have been done using 3 kinds of grinding media.The grinding efficiency,product size and distribution of Al₂O₃ and SiO₂ under different working conditions have been analysed.The results show that the separation of aluminium from silicon can be achieved by using selective grinding under the condition that product size is -200 mesh(50%),and a recovery of 30% at coarse concentrates can be realized.The features of selective grinding of bauxite in ball mill are analysed.