The aim of this proposal is to investigate at very high temperatures the effect of the used raw materials on the kinetics of in situ reactive sintering of alumina and magnesia to form improved spinel-based and ultra-low cement content refractory ceramics of interest for the steel industry. In particular, we aim to understand the effects of the shape and of the crystallographic nature of the used alumina powder in the reactive process, and the thermo-mechanical behaviour of the final material at temperatures up to 1500°C.