An Novel Method for Iron Recovery from Iron Ore Tailings with Pre-Concentration Followed by Magnetization Roasting and Magnetic Separation

Iron ore tailing is currently one of the most important secondary mineral resources. Pre-concentration followed by magnetization roasting and magnetic separation process was well recognized to be very effective in recycling iron from iron ore tailings. An iron concentrate containing 66.35% Fe with a total recovery of 57.74% was produced under the optimal experimental conditions (i.e., roasting temperature, 540 degrees C; CO concentration, 30%; roasting time, 15 min; total gas flow rate, 450 ml/min; grinding fineness 90% passing 25 mu m for roasted products, and low-intensity magnetic separation magnetic field, 104 kA/m). Mechanisms of magentization roasting were studied using XRD, SEM, and VSM, which had showed that most of the hematite was transformed into magnetite with a porous and cracked structure after roasting, and the saturated mass magnetic moment and specific susceptibility of ore were also increased significantly.