采用失重法研究了500~600℃条件下,H2还原铁矿微粉的反应过程.针对气体浓度及反应热对铁矿粉还原过程的影响,提出了传热、传质与反应耦合动力学模型,以模拟铁矿微粉气相还原过程.通过数值计算得到矿粉在不同温度下还原率随时间的变化规律,同时模拟了矿粉内温度变化与分布,以及气体浓度在微粒内部的分布与变化.模拟结果表明,矿粉在600℃下完全还原时间仅为20min,气体在15min后全部扩散到粉粒中心.
Weight loss method was used to study the reduction of fine iron ore with hydrogen at the temperatures from 500 to 600 ℃.Considering the effects of gaseous concentration and reaction heat,a non-isothermal kinetics model coupling heat and mass transfer with chemical reaction was developed to simulate the reduction process of fine oxide ore.Reduction degrees at different temperatures and times were obtained through numerical calculation.Distribution and variation of temperature and gas concentration inside the fine iron oxide particles were also simulated.The simulation result showed that fine ore particles were completely reduced within 20 min at 600 ℃,and hydrogen diffused to their center within 15 min.