Experimental Research On Exi Oolitic Hematite With Magnetic Roasting And Metallic Roasting Processes

The oolitic hematite ore, belonging to the refractory iron oxide ores, has not been utilized logically because of the characteristics of oolitic and reniform structures, fine distribution of minerals, complex properties and high content of phosphorus, silicon, and aluminium etc.. So, in this paper the reduction roasting-magnetic separation processes, including magnetic roasting separation and metallic roasting separation, are adopted to proceed the experimental researches to confirm the feasibility of the method. Besides, the X-ray diffraction analysis (XRD) and scanning electron microscope analysis (SEM) are also introduced to investigate the fundamental theoretical mechanism of the reduction behavior, which providing a theoretical basis on beneficiating the ore.The results of magnetic roasting-magnetic separation process reveal that a concentrate containing iron grade of 60.12%, iron recovery ( to run-of-mine ore and reductant ) of 77.42%, high phosphorus content of 0.62% is obtained, based on the optimum roasting conditions of pulverized coal ratio of 1:5, roasting temperature of 750℃, holding time of 1 hour, and magnetic separation conditions of rougher with magnetic field intensity of 1350Oe, rougher concentration grinding size of -0.045mm (-325mesh) accounted for 96% and two stages of magnetic cleaner with magnetic field intensity of 1150Oe, 1050Oe, respectively.By the metallic roasting condition testes and magnetic flow testes, an iron powder with iron metallization rate, iron grade, iron recovery and phosphorus grade of approximately 95%, 94%, 88% and 0.38%, is obtained, respectively, when the oolitic hematite ore is roasted at the temperature of 1050℃for 3 hours by coal-based process, and then beneficiated through permanent magnet roughing and magnetic media desliming after grinding.Besides, the magnetic roasting associated with metallic roasting flowsheet testes are also carried out to beneficiate the Exi oolitic hematite ore. The experimental results show that a final iron concentration assaying of 66.94% iron grade, 91.28% iron recovery and 1.12% phosphorus grade is acquired.