Alumina-rich refractory concretes with added spinel, periclase and dolomite: A comparative study of their microstructural evolution with temperature

Three processing routes for obtaining refractory castables within the alumina-rich zone of the Al2O3–MgO–CaO ternary phase equilibrium diagram were studied starting from mixtures of: (a) calcined alumina, synthetic spinel and calcium aluminate cements, (b) calcined alumina, magnesia and calcium aluminate cement, and (c) calcined alumina, dolomite and calcium aluminate cement. The evolution of the phases and microstructure was studied as a function of temperature and the processing route for both refractory concretes and their corresponding matrices (<125 μm).