Abstract: In order to solve the problem of high tailings grade in rough magnetic separation with annular magnetic separator, its structures are improved from two aspects: First, the magnetic screen is newly arranged at rough concentration of the annular magnetic separator, and secondly, the ore feed for the annular magnetic separator varied from the center to the periphery. The improved annular magnetic separator is adopted to the rough concentration tests in laboratory for Dagushan iron ores, and contrasted with the original devices. The results show that: in the case of the same concentrate grade, tailings grade is decreased 2.03% with the improved annular magnetic separation, and the concentrate recovery increased by 2.75%.

Key words: Magnetic separation annular column, Structure improvement, Magnetic screen, Ore feed from periphery, Tailings grade