COREX用焦在铁水中的渗碳特性

 钢铁工业是支撑国民经济发展的基础产业,同时也属于资源和能源密集型行业,随着国家严格的环保政策的逐渐实施,其面临的资源和环保要求日益增加。传统高炉炼铁生产工艺由于存在能耗高、污染物排放多的弊端,发展受到了限制,因此非高炉炼铁工艺的研究和应用日益受到钢铁行业的重视。系统研究了COREX熔融还原非高炉炼铁工艺使用的顶装焦、捣固焦和气煤焦在铁水中渗碳特性,并分析了3种不同样品在铁水中的渗碳动力学行为。研究结果表明,高温铁水与碳原子接触时发生渗碳反应的吉布斯自由能远小于Fe₃C生成反应的吉布斯自由能,焦炭与高温铁水接触被消耗的过程以渗碳反应为主。顶装焦、捣固焦和气煤焦3种焦炭样品与高温液态铁水接触后迅速发生渗碳反应,铁水中碳含量快速增加,但铁水中碳含量增加的幅度随着铁水中碳含量的升高而快速降低,在渗碳反应时间超过120 min后铁水中的碳含量基本保持恒定。3种焦炭在铁水中的渗碳速率由高到低分别为气煤焦、顶装焦和捣固焦,铁水温度对渗碳过程具有明显的影响,随着温度的升高,渗碳速率和最终铁水中的碳含量增加。动力学分析表明,捣固焦在铁水中的渗碳活化能最高,顶装焦次之,气煤焦最小。

Coke dissolution characteristics in molten iron of COREX

Iron and steel is the basic industry supporting the development of national economy, but it was also belongs to the resource and energy intensive industry. With the gradual implementation of the national environmental protection policy, it is faced with increasing resources and environmental protection. Due to the disadvantages of high energy consumption and high pollutant discharge, the development of the traditional blast furnace ironmaking process has been greatly restricted, and the non-blast furnace ironmaking process attracts more and more attention. The dissolution characteristic and kinetic behavior of different cokes are investigated in molten iron. The results showed that the process of coke and hot metal contact consumption is dominated by dissolution reaction, because the Gibbs free energy of dissolution reaction occurs when the hot metal contact with carbon atoms is much smaller than that of the formation reaction of Fe₃C. The rapid dissolution reaction occurred after coke contacting hot metal. The content of carbon in hot metal increased rapidly, but the increased range decreased rapidly with the high carbon content. After the dissolution reaction time exceeds 120 min, the carbon content in hot metal basically remains constant. The order of the dissolution reaction rate of different coke from high to low was stamp-charging coke, top-charging coke and gas coal coke. The temperature of hot metal had an obvious effect on the dissolution reaction. With the increase of temperature, both the dissolution reaction rate and the amount of carbon in hot metal increased. At last, the average activation energy of stamp-charging was largest, followed by top-charging coke, and that of gas coal coke is the smallest by kinetic analysis.