Abstract: It is pointed out that the magnetic system of the magnetic pulley and the updraft dry separator produces double-side magnetic field， while only one-side magnetic field acts on the separation space， so the utilization rate of magnetic energy is relatively low. Therefore a new magnetic system based on Halbach permanent magnet array is proposed and used to optimize the magnetic pulley and the updraft dry separator. On the basis of comparison between the old and new magnetic system， it can be seen that the new magnetic system enjoy much obvious advantages such as unilateral enhancement， high air gap magnetic density， and relatively large magnetic field utilization rate. Furthermore the tailings discarding experiment of the new magnetic system separator on a magnetic ore from Liaoning was carried out, discarding productive rate is 26.92%, magnetic iron recovery is 2.62%, loss rate of magnetic iron is 1.31%. The new magnetic separator based on Halbach permanent magnet array is a dry pre-beneficiation equipment for lean iron ore with reasonable structure and high-usage magneic energy. It can increase separation efficiency and reduce the amount of grinding capacity.

Key words: Magnetic array, Magnetic pulley, Updraft dry separator, Dry pre-beneficiation