Effect of Cl on Softening and Melting Behaviors of BF Burden

Abstract

The high-temperature simulation tests of softening and melting zone under different w(Cl-) were carried out, and based on the density functional theory, the influence mechanisms of chlorine on softening and melting behaviors of BF burden were analyzed. The results show that with the increase of w(Cl-) which bring in by sinter, the softening start temperature and softening end temperature of BF increase, and the softening temperature range becomes small, the melting start temperature increases, the dropping temperature decreases, the melting temperature range becomes small too. The softening and melting zone of BF narrows. With the increase of w(Cl-), the maximum pressure difference and the comprehensive permeability index both decrease, the permeability of the softening and melting zone enhances. The main reason for the increase of permeability is that the chlorine atom makes the Fe-O bond length increase, the stability of the structure is destroyed, the adsorption capacity of CO molecule on FeO surface is promoted, the reducing speed of FeO increases. Although chlorine can effectively reduce the reduction degradation of sinter in the BF and improve the permeability of the softening and melting zone, the metallurgical enterprises should still eliminate or reduce the chlorine element into the BF.

Keywords

• blast furnace
• chlorine
• softening and melting behavior
• adsorption