Relationship between composition and properties of MgO-spinel castables

MgO-spinel castables may be very prospective materials for high temperature application where high resistance to basic slag attack is the primary requisite and especially where carbon pick up should be avoided. Using dead-burnt magnesia, sintered bauxite-based spinel and white fused alumina as starting materials and with superfine additives, MgO-spinel castable specimens with varying matrix composition have been prepared and investigated on workability, strength, permanent linear change after heating, slag resistance and thermal shock resistance. The results are correlated with composition and microstructure. It is found that the matrix composition (Al2O3/MgO ratio in particular) has noticeable influence on the properties of these castables and optimization of properties may be done by adequate adjustment of the matrix composition.