Abstract: In order to implement the concept of green mine,achieve the goal of emission reduction and efficiency increase,improve resource utilization rate and energy saving and consumption reduction , and draw lessons from the successful application of high pressure roller grinding-dry magnetic separation process in other mines,a systematic dry grinding and dry separation test was carried out for lean magnetite ore in Waitoushan Iron Mine.The effects of different screening particle sizes (3 mm and 5 mm)and whether the middle ore returns on the separation index were investigated ,and the key process parameters were opti⁃ mized.The results show that the return of medium ore can effectively improve the metal recovery rate ,and 3mm screening is more conducive to improving the tailings rate and achieving deep tailings discarding. Combined with the demand of reducing tailings and improving efficiency in Waitoushan Iron Mine ,it is rec⁃ ommended to adopt the closed-circuit process of dry grinding and dry separation with 3 mm sieve hole and middle ore return.This scheme can achieve excellent metal recovery rate and significant tailings discarding effect while ensuring high concentrate grade,which provides an important technical basis for subsequent in ⁃ dustrial application and clean production.

Key words: high pressure roller grinding, dry magnetic separation, closed-circuit screening, circulat? ing load, magnetic pulley