Chemical Reaction of Glazed Refractory with Al-deoxidized Molten Steel

Abstract

A high alumina refractory, glazed by typical ladle slag of CaO-MgO-Al(2)O(3)-SiO(2) was investigated to understand the influence of the glazed refractory on the generation of non-metallic inclusions in Al-deoxiclized molten steel at 1 600 degrees C. The variations of microstructure and chemistry of the glazed refractory with reaction time were studied. Thermodynamic analysis was simultaneously carried out to understand the complex chemical reactions. During the reaction between the glazed refractory and molten steel, two chemical reactions were observed: between glaze and molten steel, and between glaze and original refractory. By the chemical reactions, SiO(2), in the glaze was reduced to [Si] by [Al] in molten steel. The glaze layer also gradually changed from the liquid CaO-MgO-Al(2)O(3)-SiO(2), phase with small amount of embedded spinel particles to the liquid CaO-MgO-Al(2)O(3) phase with embedded spinel and CaAl(4)O(7) particles. Severe erosion was observed in the porous spinel area of a refractory. Spinel inclusions were found as major inclusions originated from the glazed refractory. The erosion mechanism of the glazed refractory was proposed in the present study.