School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, PR China; State Key Laboratory of Mineral Processing, Beijing 100160, PR China; National-Local Joint Engineering Research Center of High-Efficient Exploitation Technology for Refractory Iron Ore Resources, Shenyang 110819, PR China.
School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, PR China; State Key Laboratory of Mineral Processing, Beijing 100160, PR China.
J Hazard Mater. 2021 Feb 15;404(Pt B):124067. doi: 10.1016/j.jhazmat.2020.124067. Epub 2020 Oct 6.
Recycling iron tailings is significant for environmental security and resource recovery, as they contain iron-rich minerals. Given the complex composition of iron minerals and the low grade of iron present in the tailings, innovative suspension roasting-magnetic separation (SRMS) technology was proposed to treat iron tailings that would separate out the iron minerals for recovery. In this study, the reduction kinetics, phase transformation, and structure evolution of the iron tailings were investigated to explain the mechanism behind magnetite production from iron tailings. These studies were conducted using chemical analyses, X-ray diffraction, Brunauer-Emmett-Teller specific surface area, and scanning electron microscopy. The results showed that high temperatures during the suspension reduction process were conducive to improving the reduction rate of the iron tailings. The best kinetics model for this reduction reaction of iron tailings is the P1 model, which demonstrated a linear increase in the conversion degree with the extension of the reaction time. The corresponding mechanism function was f(α) = 1, the apparent activation energy (E) was 51.56 kJ/mol, and the kinetics equation was k = 3.14exp(- 51.56/RT). Using the SRMS technology, magnetite gradually formed from hematite, starting at the outer particle layers and moving inward toward the core. The microcracks and pores in the surface of the particles increased, which promoted CO penetration into the particles where it reacted with the hematite. Our results provide important insight into the efficient and clean recycling of iron tailings.
回收铁尾矿对环境安全和资源回收具有重要意义，因为它们含有富含铁的矿物质。鉴于铁矿物的复杂组成和尾矿中铁的低品位，提出了创新的悬浮还原-磁选（SRMS）技术来处理铁尾矿，以分离出可回收的铁矿物。在这项研究中，研究了铁尾矿的还原动力学、相变和结构演化，以解释从铁尾矿中生产磁铁矿的机制。这些研究使用化学分析、X 射线衍射、BET 比表面积和扫描电子显微镜进行。结果表明，悬浮还原过程中的高温有利于提高铁尾矿的还原速率。该铁尾矿还原反应的最佳动力学模型是 P1 模型，该模型表明转化率随反应时间的延长呈线性增加。相应的机制函数为 f(α) = 1，表观活化能（E）为 51.56 kJ/mol，动力学方程为 k = 3.14exp(- 51.56/RT)。使用 SRMS 技术，磁铁矿逐渐从赤铁矿形成，从外颗粒层开始向内芯移动。颗粒表面的微裂纹和孔隙增加，促进了 CO 渗透到与赤铁矿反应的颗粒内部。我们的结果为铁尾矿的高效清洁回收提供了重要的见解。
