An Efficient Process to Recover Iron from Bayer Red Mud

We have investigated Bayer red mud with a TFe content of 26.86% collected from the Pingguo area of China, and have found that iron is the key metal affecting the extraction of valuable components such as Sc, Ti, and Ga. Based on this, an efficient process of roasting with calcium salt and magnetic separation has been proposed to extract iron from the Bayer red mud. Coke, calcium chloride, and calcium hypochlorite were put into a resistance furnace for roasting, and iron was converted from low-intensity magnetic iron minerals to high-intensity magnetic iron minerals. Iron was recovered from the roasted ore by low-intensity magnetic separation after wet grinding. We found that calcium chloride and calcium hypochlorite can promote FeO to be reduced to Fe-0 on the coke surface after FeCl3 is added, and that CaO produced by calcite decomposition can promote FeSiO3 to be reduced to Fe-0, which significantly increases the content of metal iron in the roasted ore. An iron concentrate with a TFe content of 86.86% and an iron recovery of 91.48% was obtained. The main minerals in the iron concentrate were Fe-0 and Fe3O4, which accounted for 58.78% and 20.37% of the total iron, respectively.