Influence of Silicon on Desulfurization of Al-Killed Steel by CaO-Al2O3 Slag Contained FeO and MnO

摘要

Industry trials of slag-washing desulfurization in LD tapping process are performed to study the influence of silicon on desulfurization of Al-killed steel using CaO-Al2O3 slag contained FeO and MnO. Influence of silicon on desulfurization is found to be great, while the influences of aluminum and manganese on desulfurization are negligible. Oxygen activity at slag-steel interface together with the (FeO+MnO) content in slag, decreased with the rise of silicon content, which is considered as the main reason of different desulfurization efficiencies between Si-free steel and Si-containing steel. Oxygen activity at slag-steel interface is reduced more sharply by increasing the silicon content than that by increasing the aluminum content. As a result, desulfurization efficiency can be enhanced significantly with the rise of silicon content, rather than the aluminum content. Furthermore, the influence of silicon on desulfurization can be magnified if the slag contained FeO and MnO, while negligible for the slag with few FeO and MnO.