Development of Magnetic Processing Circuit for Oxidized Iron Ore after Magnetic Roasting

The process of wet magnetic separation of oxidized ore from the deposit of Abail, Republic of Kazakhstan, is studied. Kinetics of roasted product milling is analyzed, and the optimal size is recommended for the fist stage of milling as −0.071 mm at the content of 55–60%. The accomplished magnetic analysis of different size products shows that the decrease in size causes no increment of iron in the magnetic product and iron is at the level of 63.0 mass%. The scanning electron microscopy reveals that the roasted and magnetic products contain floccules of gangue and magnetite particles which transfer into magnetic fraction and worsen its quality. Two schemes are proposed for decomposition of floccules: multistage desliming with regard to sedimentation velocity in liquid medium and attrition with deffloculation agent. It is recommended to apply the two-stage circuit with milling, desliming and wet magnetic separation, which allows production of iron concentrate with iron content of 67% at recovery of 76.5%.