A new approach for recovering iron from iron ore tailings using suspension magnetization roasting: A pilot-scale study

Iron ore tailings, which are important secondary resources, have outstanding latent application value in iron recovery. In this study, a pilot-scale experiment on the iron recovery from iron ore tailings was investigated using innovative technology of pre-concentration and suspension magnetization roasting (SMR), followed by magnetic separation and flotation. An iron concentrate containing 58.67% Fe at an iron recovery of 57.82% was obtained under the optimal SMR conditions: a feed rate of 100 kg/h, roasting temperature of 530 degrees C, CO reducing gas of 3.5 m(3)/h, and N-2 fluidizing gas of 3.0 m(3)/h. During the SMR process, weakly magnetic hematite and siderite in the iron ore tailings were converted to strongly magnetic magnetite with an average magnetic conversion rate of 81.71%. The SMR reactor exhibited good performance with well-functioning equipment, controllable process parameters, and the production of a high-quality roasted product. This innovative SMR technology is a quantum leap in separating refractory iron ore, which opens up a new approach for the efficient recovery of iron from iron ore tailings. (C) 2019 Elsevier B.V. All rights reserved.