Medium Characteristics on Selective Grinding of Low Grade Bauxite

Selective grinding of bauxite with ratio of Al2O3/SiO2(A/S) 4.4 at ball mill were studied in order to investigate the effect of grinding media characteristics on selective grinding of bauxite. Results show that when diameter of ball media is Φ15mm, selective grinding effect is best and at this moment A/S of the product at -0.5+0.28mm granularity is up to 7.5. Ball/powder weight ratio, charge rate, and size composition of grinding media have little influences on particle size composition of powder product, but have great influences on the A/S at different granularity powder product. At condition of size composition of grinding media Φ30mm:Φ20mm:Φ15mm＝20%:50%:30% and charge rate 40%, the grinding results are best and at the moment ωAl2O3/SiO2 is up to 7.5, yield 27%, and Al2O3 recovery 30%.