Reactions between magnesia-chrome refractories and copper converter slags: Corrosion behavior and prevention by Fe-rich layer formation

Magnesia-chrome refractories act as a lining for electric furnaces when valuable metals are recovered from copper converter slags. However, the lifetime of refractories does not exceed six months. To address the leakage problem, the corrosion behavior of a magnesia-chrome refractory immersed in a copper converter slag at different temperatures was investigated by adopting static corrosion test. The thermodynamic simulations of solubility and reactions of the slag with the refractory were first conducted. The laboratory corroded samples showed that Fe and Si penetrated the refractory material, resulting in material dissolution and reactive corrosions. Meanwhile, an Fe-rich layer formed at the slag-refractory interface which could prevent further corrosion. Given the Fe3O4 content, 1300 degrees C was concluded as the optimal temperature to facilitate the formation of the protective layer. The laboratory findings were in agreement with the simulation well. On the basis of the corrosion behavior, this study proposed a novel approach that prolongs the lifetime of furnaces.