A basic alumina-spinel low cement castable (LCC) composed of sintered bauxite, reactive alumina, calcined alumina, calcined magnesia, microsilica, and high alumina refractory cement was prepared (castable A) to which 5% sodium hexa-meta phosphate was later added (castable B) to prepare samples for heat treatment at 110ºC, 900ºC, and 1400ºC. Bulk Density (BD), Apparent Porosity (AP), and Cold Cr...