Refractory bodies of 65 wt% Al2O3were prepared from a mixture of calcined alumina and raw kaolin with the addition of Cr2O3up to 15 wt%. The Cr2O3addition effectively enhances slag resistance and reduces mullite formation. Petrographic analysis of the refractories after the slag test suggests that Cr2O3increases the viscosity of both the glassy phase in the refractory as well as the slag, thereby retarding slag penetration and reaction at elevated temperature.