Abstract: In order to stabilize the separation index of field production，further open the intergrowth of magnetite，dissociate gangue minerals，and improve the enrichment of iron concentrate in the subsequent magnetic separation process，the technology of fine grinding and re-dressing of iron concentrate was studied by using TM series tower mills which were independently developed by Sinosteel Tianyuan Technology Co.，Ltd. The results show that when the grinding fineness is -0.038 mm 70% and the magnetic separa⁃ tion field is 800 mT，the grade of magnetic separation concentrate is 71.51% and the recovery rate is 97.84%，application results is obvious. Ultra-pure iron concentrate can be prepared by TM series tower mill for ultrafine grinding and magnetic separation with wet weak magnetic separator.

Key words: tower mill, ultra-fine grinding, stage grinding