Abstract: With the change of ore properties，the processing capacity of the secondary separation op⁃ eration area of the Changling concentrator increases，which causes problems such as large fluctuation of flo⁃ tation flow and fluctuation of concentrate index. In order to efficiently recover fine-grained magnetite，the high-efficiency magnetic separation process was used to replace the flotation process，and the elutriation machine was used to treat fine-grained magnetite. The effects of feed concentration，magnetic field strength and water flow of the elutriation machine on the separation index were studied. The results show that under the optimum conditions of TFe grade of 51.43%，feed concentration of 40%，fixed magnetic field strength of 94.4 kA/m，circulating magnetic field strength of 86.4 kA/m，compensated magnetic field strength of 86.4 kA/m and water flow of 1 150 L/h，the iron grade of concentrate is 67.03%，the recovery rate is 93.82%，and the iron grade of tailings is 11.26%.

Key words: fine-grained magnetite, high-efficiency magnetic separation, process optimization