Reactions Between MgO-C Refractory, Molten Slag and Metal

Abstract

The behavior of MgO-C refractory-slag-metal system, which is caused by the reactions such as the dissolution of MgO and graphite in the refractory into slag and metal respectively and the generation of gas bubbles, was observed directly by using a high temperature X-ray radiographic apparatus and analysed theoretically. The local corrosion is regarded as due to the cyclic dissolution of MgO and graphite in the refractory into slag and metal phase respectively. The local corrosion is greatly influenced by the generation position of gas bubbles and the number of gas bubbles generated. Bubbles generated in the refractory-slag-metal three-phase boundary restrain the local corrosion, while bubbles generated at the refractory-metal interface enhance the local corrosion. Gas bubbles form mainly according to the reaction between (FeO) in the slag film and C_(s) in the refractory contacting with the slag film: (FeO)+C_(s)=Fe_(l)+CO_(g). Some fundamental principles to improve MgO-C refractory were put foward.