Spinel saturation of a PbO based slag as a method to mitigate the chemical degradation of magnesia-chromite bricks

Abstract

For nonferrous smelters, the chemical wear of the magnesia-chromite bricks caused by the direct contact with the slag leads to regular replacement of the lining before complete failure. This is a costly and time intensive procedure. Increasing the lining’s lifetime, by reducing the chemical wear, would result in a reduction of both the installation cost and the production losses. In this paper, the potential of changing the slag composition to limit the chemical dissolution rate by saturating the slag in spinel components is investigated by isothermal static finger tests. When saturating the slag in spinel by adding Fe2O3, a spinel layer forms at the interface between the refractory sample and the liquid slag. As the dissolution of MgO from the refractory in the slag is now controlled by solid state diffusion through the new spinel layer, the chemical wear rate is substantially decreased, thereby increasing the lifetime of the lining.