Effect of ZnO level in secondary copper smelting slags on slag/magnesia-chromite refractory interactions

To determine the effect of ZnO in ZnO-containing fayalite (ZFS) slags on the degradation of magnesia-chromite refractories, the corrosion behaviour of a direct-bonded magnesia-chromite refractory was studied by rotating refractory finger tests at 1200 °C under reducing atmosphere. In addition, MgO crucible tests at these conditions were performed to investigate in particular the effect of ZnO on the slag/MgO interaction. The dissolution of MgO from periclase into the ZFS slags is not enhanced by increasing the ZnO content in the slags. (Fe,Mg,Zn)2SiO4 olivine and (Fe,Mg,Zn)O solid solution are the only two products in the slag/MgO interfacial reactions, even when the ZnO content in the ZFS slag reaches 16.7 wt%. The diffusion of ZnO into the chromite grains to form the (Fe,Mg,Zn)(Fe,Al,Cr)2O4 spinel was favoured with increasing the ZnO content in ZFS slags.