Degradation mechanisms and use of refractory linings in copper production processes: A critical review

The use and degradation of refractory linings in copper furnaces are discussed, thereby describing the main steps taken at the research, development and industrial level to minimize refractory wear. Which combination of chemical, thermal and mechanical degradation mechanisms is dominant depends on many factors such as the furnace type, the lining design, including the selection of the refractory type, and the process conditions. Magnesia-chrome bricks are widely used to line copper furnaces, despite the potential risk for the formation of hexavalent Cr under specific conditions, typically in the presence of alkali or alkaline earth oxides. To understand and predict refractory degradation, both post-mortem investigations and lab scale tests are considered to be helpful tools, thereby supported by phase diagram investigations and thermodynamic and kinetic calculations. This review concludes with refractory selection and use on the industrial level, including the waste and recycling management of spent refractories.