焦炭床内铁水渗碳行为

摘要：高炉冶炼过程中铁水最终渗碳量接近饱和，相比而言，闪速炉中没有固体炉料的压迫作用，无法发生像高炉炉缸内死料柱根部与铁水之间的渗碳反应，最终渗碳量难以预料。为此，以电解铁和化学纯石墨为原料，利用管式电阻炉升温到1855K熔化铁块，以高纯Ar作为保护气体研究焦炭床内铁水渗碳行为，并对铁水渗碳行为进行数值模拟，为闪速炼铁工业化打下基础。实验结果表明，终铁C含量随焦炭粒度增大和渗碳床高度降低而减小，且铁水初始C含量对终铁C含量具有较大影响。对于不同条件下铁水渗碳反应中C元素的迁移规律，基于VB编程技术进行了数值模拟，模拟结果与高温实验结果较吻合，相对误差在3%以内。渗流速度控制因子始终控制在05左右，即铁水在焦炭床中的平均速度为初始滴落速度的一半左右。

Carburizing behavior of molten iron in coke bed

The final C content of molten iron in the blast furnace smelting process is close to saturation, while that in flash ironmaking process is unexpected, since there is no solid charge pressing the deadman and consequently no carburization reaction that occurs between the deadman bottom and the hot metal. In order to study the process of coke dissolving into the molten iron in coke bed, a series of experiments and relevant numerical simulations were carried out. Electrolytic iron and chemically pure grapaite were used as raw meterials, and a tubular resistance furnace was employed to heat the samples up to 1823K until melting them. The high purity Ar was injected as protective gas throughout the experiments. The experimental results show that the C content in the final iron decreases with increasing the coke particle size and reducing the height of the carburized bed. The initial C content in the molten iron has a great influence on the final carburization value. To clarify the migration law of C element in the process of molten iron carburizing reaction under different conditions, the numerical simulations were conducted based on VB programing technology. The simulated results are in good agreement with the high temperature experimental data, with the relative error of below 3%. The percolation velocity control factor is at about 05, in other words, the average velocity of molten iron in the coke bed is about half of the initial dropping velocity.