High Temperature Corrosion Mechanisms of Refractories and Ferro-Alloy Slags

Refractory linings in pyrometallurgical furnaces are attacked by various process phases (e.g. metal, slag, gas). However, refractories are the barrier between these phases and the environment: refractory damages and consequent furnace failure can cause severe damages including potential danger for workers/operators. Hence, refractory corrosion and attack of molten phases require attention to study the mechanisms and effects on refractory performance and lifetime. This is of special importance in ferroalloys production, where temperatures are generally even higher than in base metal processes and the corrosion effects therefore more pronounced.To understand the nature of the reactions involved in refractory corrosion, it is crucial to have an understanding of the chemical equilibria and the thermodynamics of the reactions.The present work studies the high-temperature interactions between refractories and molten slags, comprising theoretical thermodynamic analysis (FactSage™) and experimental work (hot-stage microscopy) to better understand the corrosion mechanisms and draw implications for improving the refractory performance and lifetime.The results will provide a framework for investigating refractory corrosion processes and trigger research efforts in the area of thermodynamic applications, optimizations and simulations in high-temperature processes.