Abstract: In order to solve the problem of blockage in the production process of a magnetite mine in Anhui Province，aiming at the problem of large mud content，the desliming and discarding test was carried out on the ore under pre-screening and screening before medium crushing. The results show that: ① The tailings with yield of 48.37%，total iron grade of 13.12% and magnetic iron grade of 4.62% can be discarded by dry magnetic separation process，and the recovery rate of magnetic iron is 79.91%. ② The tailings with yield of 41.80%，total iron grade of 11.78% and magnetic iron grade of 0.64% can be discarded by dry magnetic separation process for 75~20 mm and 20~0 mm raw ore，and comprehensive iron concentrate with total iron grade of 18.37% and magnetic iron grade of 8.81% can be obtained. ③The tailings with yield of 37.75%，total iron grade of 9.35% and magnetic iron grade of 0.33% can be discarded by using high pressure roller mill + wet magnetic separation process. The concentrate grade is increased to 22.89%，the recovery rate of magnetic iron is 98.89%，and the wet preconcentration index is better.

Key words: desliming and discavding tailings, magnetite, preselection