As well as MgO–MA bricks, MgO–MA castables have been developed. Firstgeneration
MgO–MA castables were developed using phosphate binders (32).
Fused alumina clinkers were added to obtain a slightly positive permanent
volume change once fired at 16008C. Phosphate binders were supposed to
improve the hydration resistance of MgO fines. On adding Al2O3, slag penetration
resistance improved slightly, but structural spalling resistance improved
significantly although hot strength deteriorated. Corrosion resistance tended to
decrease with Al2O3 addition but was still better in basic slags when compared
to a pure alumina castable.