铁渣熔体穿行焦炭床的渗碳机理

Carburization mechanism of molten iron-slag passing through coke bed

由于高炉炼铁工艺流程长、对冶金焦依赖性强,尤其是焦化、烧结、球团等原料制备过程中产生的环境问题,因此该工艺的发展受到严重制约。闪速炼铁工艺是近年来提出的一种新兴熔融还原炼铁技术,发展前景可期。不同于高炉炼铁,闪速炉中没有焦炭死料柱,其铁水渗碳量难以预估。为此,以金属化球团和工业焦炭为原料,设计实验研究焦炭床内铁渣熔体渗碳行为,并基于VB编程对铁渣熔体渗碳行为进行了数值模拟。实验结果表明,球团矿金属化率对终铁C含量有较大的影响,渗碳量(w[C],%)随着金属化率(x)的提高呈指数级增加。当焦炭床高度为50mm时,拟合而得w[C]=0.014 34+exp((x-84.2)/3.253 48);基于VB编程进行的数值模拟结果与高温实验结果吻合较好,相对误差在10%以内,可直观展示铁渣熔体流经焦炭床时碳含量的变化规律。

The development of blast furnace ironmaking process is seriously constrained for its long process and high reliability to metallurgical coke,especially the environmental problems arising from raw material preparation processes such as coking,sintering and pelletizing.Flash ironmaking process is a new promising smelting reduction ironmaking technology proposed in recent years.However,the carburization of hot metal in this process is difficult to predict,which is resulted from the lack of coke deadman in flash furnace compared to that in blast furnace.In order to study the carburizing behavior of molten iron-slag in coke bed,a series of experiments were designed using the metallic pellet and industrial coke as raw material,and the correspongding numerical simulation is carried out based on VB program.The experimental results show that the increase of metallization rate has an exponential increasing influence on the final carbon content of hot metal.When the height of coke bed is 50 mm,the relationship can be expressed as w[C]=0.01434+exp((x-84.2)/3.25348).The numerical simulation results based on VB are in good agreements with the high temperature experimental results,the relative errors are all bellow 10%.Furthermore,the change of carbon content in the flow of molten iron through the coke bed is visually displayed.