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系统分析了铁矿石还原性的影响因素以及铁矿石的气固还原动力学特征,铁矿石的化学成分、孔隙率和矿物组成对其还原性都有影响,总体来看,铁矿石中的碱性氧化物对铁矿石的还原有促进作用,而酸性氧化物对其还原有阻碍作用。提高铁矿石中微气孔的比例以及提高还原性好的矿物,如铁酸钙的含量可改善铁矿石的还原性;对于铁氧化物气固还原动力学的研究大多采用未反应核模型,在还原的不同阶段具有不同的限制性环节,比如在浮士体还原到金属铁阶段,前期还原反应由气体内扩散与界面化学反应混合控制,后期界面化学反应为还原反应的控制环节。总结前期的研究结果,结合当前资源现状提出了今后铁矿石还原行为的2个研究方向:①加强Al2O3、K2O、Na2O、ZnO等杂质元素和有害元素对铁矿石还原性影响研究;②加强高炉实际含铁原料,如烧结矿、球团矿和块矿的气固还原动力学研究。
The factors affecting the reducibility of iron ore and the gas-solid kinetic characteristics of iron ore are systematically analyzed. The chemical composition, porosity and mineral composition of iron ore have an impact on their reducibility. Generally speaking, iron ore The basic oxides in the reduction of iron ore has a catalytic role, while the acidic oxide has an inhibitory effect on the reduction. Improve the proportion of micro-pores in iron ore and improve the reduction of good minerals, such as calcium ferrite content can improve the reduction of iron ore; for the iron oxide gas-solid kinetics of mostly unreacted nuclear model, Different stages of reduction have different restrictive links. For example, in the stage of reduction of the fusilli to metallic iron, the early reduction reaction is controlled by the mixture of gas diffusion and interfacial chemical reaction, and the chemical reaction of the latter interface is the control of the reduction reaction. Summarizing the previous research results and combining with the present resources, two research directions of iron ore reduction in the future are put forward: (1) to study the effect of impurity elements and harmful elements such as Al2O3, K2O, Na2O and ZnO on the reducibility of iron ore; Gas-solid reduction kinetics of actual iron-bearing raw materials in blast furnace, such as sinter, pellet and lump ore.