铁矿石焙烧动力学研究现状及发展

Present Situation and Prospects of Research on Kinetics Study of Iron Ore Roasting

焙烧—磁选法是处理低品位难选氧化铁矿石的有效方法。归纳了铁矿焙烧过程动力学研究常用的3种表征方法,着重介绍了基于热重分析技术的静态法和动态法在铁矿石焙烧过程动力学研究方面的运用。总结了磁化焙烧、直接还原和深度还原过程动力学近年来的研究成果。指出菱铁矿磁化焙烧过程根据TG和DTG曲线可分为两个阶段,其反应机理分别符合随机核化和核生长机理;铁矿石直接还原过程根据TG和DTG曲线分为几个阶段,再由各阶段活化能的差异分为缓慢反应阶段和快速反应阶段,由此可以找出焙烧过程的限制环节;赤铁矿在深度还原过程中经历缓慢反应—快速反应—趋于平衡3个阶段,整体反应符合随机成核及长大模型,活化能约为320 k J/mol。指出今后应加强对实际矿石磁化焙烧动力学的研究,为实际难选矿磁化焙烧关键技术提供理论支撑;还应注重焙烧过程热力学与动力学研究的结合,对焙烧过程进行计算机模拟等方面的研究。

Roasting-magnetic separation is an effective way to treat low grade and refractory iron oxide ore. Three commonly used representation methods about dynamics research on iron ore roasting process was concluded,application of both static and dynamic methods used in iron ore roasting process based on the thermogravimetric analysis technology was emphasized. Dynamics research on magnetization roasting,direct reduction and deep reduction process lately is summarized. It is pointed out that magnetization roasting process of siderite can be divided into two stages according to the TG and DTG curves,and its reaction mechanism meets random nucleation and growth mechanism respectively; Direct reduction process on iron ore can be divided into several stages according to the TG and DTG curve,and then classified into slow or rapid reaction stage,from which restricted link of the roasting process will be identified; Hematite will endure three stages,including slow reactionquick reaction-tendency to equilibrium stage,in the process of deep reduction,the overall reaction fits the random nucleation and growth models,the activation energy is about 320 k J / mol. It is pointed out that dynamics research on magnetization roasting about natural ore should be emphasized in the future,and provides theoretical support for refractory iron ore roasting key technology. Closely attention should also be paid on combination of thermodynamics and dynamics research during roasting operation,as well as computer simulation research during roasting.