The main role of the ZrO2–MgO–CaO and ZrO2–MgO–CaO–SiO2 systems in the field of refractories

The increasing severity of the working conditions of refractories together with the necessity of available and economically feasible raw materials have changed the design approaches towards materials experiencing “in situ” modifications during use. The systems ZrO2–MgO–CaO and ZrO2–MgO–CaO–SiO2 are key ones in refractory technology due to the high temperatures for liquid formation involved. Apart from the well-known ZrO2, MgO, MgO-C and MgO·CaO commercial refractories, calcium zirconate (CZ, CaZrO3)-based materials have been proposed due to the low thermal conductivity and high refractoriness of CZ. Naturally occurring minerals as dolomite, baddeleyite or zircon are potential raw material candidates for the fabrication of relatively low cost MgO-CZ-based refractories. This work discusses guidelines for the formulation of basic refractories with CZ-based matrices. The effect of composition on the microstructural development, the mechanical behaviour and the corrosion resistance against cement clinker are discussed.