Freeze Lining at Umicore Hoboken—Progress and Challenges

In copper smelting and pyrometallurgy, refractory degradation is a major issue affecting operations, safety, and profitability. One solution is intense wall cooling using water-cooled copper blocks, which form a protective freeze lining of solidified slag on furnace walls. This layer protects the refractory and extends its life, even allowing operation with minimal or no refractory. However, freeze lining poses challenges, notably the risk of steam explosions that can occur especially if the cooling block gets damaged, exposing water (coolant) to the molten bath. Thus, adopting freeze lining should be gradual and based on fundamental knowledge and competence building, including at Umicore Hoboken. Current work addresses concerns about freeze lining, such as the impact of a dynamic slag composition on its thickness and stability. It also summarizes research on mitigating risks, like using alternative coolants to prevent steam explosions.