Abstract: In order to solve the problems of low recovery rate of fine particles, serious inclusion and high tailings running rate in the pre-concentration of magnetite by traditional dry magnetic separator, a comparative test of pre-concentration process between traditional dry magnetic separator and new LCGJ se‐ ries balanced dry separator was carried out systematically by taking a high pressure roller mill product of magnetite in Inner Mongolia as the research object. The results show that under the optimum conditions, the TFe grade of concentrate is 38.98% and the mFe grade of tailings is 1.95%. The new type of balanced dry separator has significantly improved the recovery efficiency and separation accuracy of fine-grained minerals through technical improvements such as large cylinder diameter design, multi-magnetic pole and small pole distance magnetic system structure, and segmented magnetic separation. Under the conditions of magnetic field strength of 318.47 kA/m and drum speed of 80 r/min, the TFe grade of concentrate obtained is 40.69%, and the mFe grade of tailings is reduced to 0.95%, which effectively reduces the inclusion and tail running of concentrate in the dry pre-concentration process, and greatly improves the separation effi‐ ciency and concentrate quality. The balanced dry separator has obvious advantages in optimizing the pre�concentration efficiency of magnetite. The research results provide a feasible dry preconcentration technical scheme for the efficient, low-carbon and economic development of fine-grained magnetite resources in wa‐ ter-deficient areas.

Key words: magnetite, dry magnetic separation, LCGJ balanced dry separator, magnetic system de‐ sign, magnetic agglomeration, entrainment, tailings loss