Magnetizing roasting via a fluidized bed,which was recognized as an efficient method for beneficiation of low-grade iron ores,has attracted much attention in China recently due to the fluctuation of the international iron ore market.In order to examine the effects of magnetic properties on the separability and to optimize the operating parameters,magnetic susceptibility and coercivity of a low-grade hematite after magnetizing reduction and reoxidation under different conditions were investigated.It was found that the magnetic susceptibility of roasted ore increased with reduction degree and particle diameter to different degrees.The magnetite was re-oxidized to maghemite when the temperature was below 400℃,and the magnetic susceptibility decreased slightly.The recovery efficiency decreased notably with the particle size for very fine grains although no significant change was found in magnetic susceptibility.The coercivity and remanence of roasted ores decreased with increasing roasting temperature.The scanning electron microscope(SEM) study showed that more cracks were produced by the reoxidation of reduced ores,which could possibly favor the intergranular fracturing and the liberation for further treatment. Magnetizing roasting via a fluidized bed, which was recognized as an efficient method for beneficiation of low-grade iron ores, has attracted much attention in China recently due to the fluctuation of the international iron ore market. In order to examine the effects of magnetic properties on the separability and to optimize the operating parameters, magnetic susceptibility and coercivity of a low-grade hematite after magnetization reduction and reoxidation under different conditions were investigated. It was found that the magnetic susceptibility of roasted ore increased with reduction degree and particle diameter to different degrees. The magnetite was re-oxidized to maghemite when the temperature was below 400 ° C, and the magnetic susceptibility decreased decreased. The recovery efficiency decreased notably with the particle size for very fine grains although no significant change was found in magnetic susceptibility. The coercivity and remanence of roasted ores decreased with increasing roasti ng temperature. The scanning electron microscope (SEM) study showed that more cracks were produced by the reoxidation of reduced ores, which could have favored the intergranular fracturing and the liberation for further treatment.