混气悬浮磁化焙烧铁尾矿及其磁分选效果

为实现铁尾矿资源化回收利用，以H₂、CO、CO₂和N₂模拟还原混气对铁尾矿进行悬浮磁化焙烧，通过磁选获得铁精矿。探究温度、时间、H₂和CO占比对铁精矿铁品位和回收率的影响，采用X射线衍射、振动样品强磁计、X射线光电子能谱、BET表面分析和扫描电子显微镜X光微区分析方法，探究悬浮磁化焙烧磁选过程中晶相结构变化和反应机理。结果表明，铁尾矿在温度、时间和H₂∶CO∶CO₂∶N₂（体积比）分别为600 ℃、10 min和20∶15∶15∶50时，铁精矿铁品位和回收率最优分别为62.06%和98.03%。铁精矿饱和磁化强度由0.77 Am²·kg⁻¹提升到59.43 Am²·kg^-1。悬浮磁化焙烧能有效将赤铁矿针铁矿还原为磁铁矿，且BET表面积提升了13.1676 m²·g⁻¹，并能通过磁选有效分离Fe₃O₄和SiO₂等脉石。本研究可为从铁尾矿中回收铁资源提供参考。

Recycling Fe3O4 from iron tailings via suspension magnetized roasting by mixed gas and magnetic separation

For recycling Fe3O4 from iron tailing, iron tailing was reduced by mixed gas of H2, CO, CO2 and N2, and then magnetic separated. In this study, the effects of temperature, time, proportion of H2 and CO on iron grade and recovery ratio were investigated. XRD, VSM, XPS, BET and SEM-EDS methods were used to reveal the diversification of crystal structure and reaction mechanisms in the process of suspension magnetized roasting and magnetic separation. The optimal iron grade of 62.06% and recovery ratio of 98.03% was obtained via suspension magnetized roasted at 600 ℃, 10 min, and H2: CO: CO2: N2 of 20: 15: 15: 50. The saturation magnetization of iron concentrate had been increased from 0.77 to 59.43 Am2·kg−1. The suspension magnetized roasting can effectively reduce the hematite goethite into magnetite, and the BET surface area of tailing was increased by 13.1676 m2·g−1. Finally, magnetic separation was used for effectively separating Fe3O4 and SiO2 form reduced iron tailing. This study provided an effective method to recovery iron form the disposed iron tailing for sustainable development of the mine environment.