高炉富氢冶炼时渣-焦界面的润湿行为

Wetting behavior of slag-coke interface during hydrogen-rich smelting in blast furnace

高炉富氢冶炼后焦炭的气化反应行为发生了较大变化,改变了渣-焦界面润湿性,这对高炉的透气、透液性有着重要影响。利用渣-焦界面接触角测定试验研究了不同条件对渣-焦界面润湿性的影响规律,利用激光共聚焦显微镜对焦炭表面的三维形貌进行表征并分析了渣-焦界面作用机理。结果表明,随着焦炭与H2O反应时间的增加,焦炭表面孔隙率逐渐增大,熔渣在焦炭表面的润湿驱动力增强,使熔渣与焦炭表面的接触角、界面张力和界面反应速率均随之降低,界面黏附功增大,熔渣在焦炭表面的润湿性改善。随着熔渣碱度的降低以及w(FeO)的增大,熔渣与焦炭表面的接触角和界面张力降低,界面反应速率和界面黏附功增加,熔渣在焦炭表面的润湿性改善;碱度在1.1~1.3变化时渣-焦界面润湿性变化幅度相对较小,w(FeO)由5%增加至10%时润湿性改善最明显;熔渣碱度降低以及w(FeO)增大均使熔渣对焦炭表面的溶蚀作用增加,使焦炭表面孔隙率和孔隙深度均明显增大,大气孔增多,熔渣对焦炭的黏附作用增强,不利于高炉生产。

After hydrogen-rich smelting in blast furnaces,the gasification reaction behavior of coke has undergone significant changes,which directly affects the wettability of the slag-coke interface,and has a significant impact on the permeability and liquid permeability of blast furnaces.The influences of different conditions on the wettability of slag-coke interface were studied by measuring the contact angle of slag-coke interface.The three-dimensional morphologies of the coke surface were characterized using a laser confocal microscope and the mechanism of the slag-coke interface was analyzed.The results indicate that with the increase of reaction time between coke and H_2O,the surface porosity of coke increases,enhancing the wetting driving force of slag on the coke surface,reducing the contact angle,interfacial surface tension,and interfacial reaction rate between slag and coke surface.The interfacial adhesion work increases,and the wettability of slag-coke on the coke surface improves.As the slag basicity decreases and w(FeO)increases,the contact angle and interfacial tension between the slag and coke surface decrease,the interfacial reaction rate and adhesion work increase,and the wettability of slag-coke improves.The change in wettability is relatively small when the basicity ranges from 1.1 to 1.3,and the improvement in wettability is most significant when w(FeO)increases from 5%to 10%.The decrease in basicity and the increase in w(FeO)both increase the corrosion effect of slag on the coke surface,resulting in a significant increase in surface porosity and pore depth of coke,increase in atmospheric pores,and enhanced adhesion effect of slag on coke,which is not conducive to blast furnace production.