Thermal conductivity of used copper converter bricks

Peirce-Smith converters are commonly used in copper smelting and have a refractory lining of MgO-based bricks. There are multiple possible sources of refractory degradation, one of which is the thermal stress generated during operation. This is thought to be aggravated by the infiltration of metal into the brick structure, which is believed to increase the thermal conductivity of the refractory. In this work, 10 postmortem magnesia-chrome refractory bricks taken from a Peirce-Smith converter in Boliden Harjavalta were studied using laser flash analysis, thermodynamic modeling utilizing FactSage software, and mineralogical observations. Slag interaction was found to have occurred at the hot face of several bricks. Infiltration of metal and matte was found to increase the thermal conductivity of the brick, but the difference between samples with and without metal/matte infiltration was not as significant as expected. The thermal conductivity of the postmortem bricks without metal/matte infiltration was found to be 3-4 W/(m·K) at 800 °C, whereas the thermal conductivity of samples with metal/matte infiltration was found to be between 3 W and 6 W/(m·K) at 800 °C.