Application of suspension magnetization roasting as technology for high-efficiency separation of valuable iron minerals from high-iron bauxite
(1. School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China;
2. National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources, Shenyang 110819, China;
3. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China)
2. National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources, Shenyang 110819, China;
3. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China)
Abstract: A technology for suspension magnetization roasting-magnetic separation was proposed to separate iron minerals for recovery. The optimum parameters were as follows: a roasting temperature of 650 °C, a roasting time of 20 min, a CO concentration of 20%, and particles with a size less than 37 μm accounting for 67.14% of the roasted product. The total iron content and iron recovery of the magnetic concentrate were 56.71% and 90.50%, respectively. The phase transformation, magnetic transition, and microstructure evolution were systematically characterized through iron chemical phase analysis, X-ray diffraction, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results demonstrated the transformation of hematite to magnetite, with the iron content in magnetite increasing from 0.41% in the raw ore to 91.47% in the roasted product.
Key words: high-iron bauxite; suspension magnetization roasting; comprehensive utilization; magnetic separation; phase transformation