Abstract: Bauxite from Kelan,Shanxi province,is low grade diasporic bauxite,valuable minerals and gangue minerals are closely associated with each other,which results in sorting difficult.Through mineralogical study and mineral processing experiments,for the bauxite ores of A/S=4.14,the test press of "selective grinding-positive flotation" were carried out,positive flotation used new collector ZMC-3,through one roughing,two cleanings and two scavengings,obtained the A/S of final concentrate was 9.27 and recovery rate of Al₂O₃ was 72.60%.The index of concentrate is better,reach the requirements of Bayer process.