Abstract

Al2O3-chromite refractories have been proven to be more resistant against fayalitic (FeO-Fe2O3-SiO2) slags than MgO-chromite refractories in the primary copper smelting process. It is therefore expected that such Al2O3-chromite refractories could be used in the lining of secondary copper smelters to extend the lifetime of these furnaces. However, secondary raw materials are introduced in secondary copper production processes compared to primary copper production, leading to changes in the composition of the slag. ZnO, for example, can be present in the secondary smelting slag forming a ZnO-containing fayalite (ZFS) slag.  With ZnO present in the slag, both the physical and chemical properties of the slag are varied, which can consequently affect the corrosion behaviour of Al2O3-chromite refractories. Therefore, the interactions between Al2O3-chromite refractories and ZnO-containing fayalite slags was investigated in this work by static refractory finger tests and Al2O3 crucible tests at 1200 °C under Ar atmosphere. The microstructure of the corroded refractory samples and the slag composition were analyzed by electron probe micro-analysis equipped with wavelength dispersive spectroscopy (EPMA-WDS). The influence of the ZnO level on the Al2O3 dissolution and the Al2O3/slag interfacial reactions was studied. The experimental results from the Al2O3 crucible tests were interpreted and supported by thermodynamic calculations.