Alumina–zircon refractory materials for lining of the basin of glass furnaces: Effect of processing technique and TiO2 addition

Three batches composed of calcined alumina and Egyptian zircon sand were designed to produce refractory materials containing alumina–mullite–monoclinic zirconia composites as lining materials for the basin of electric glass furnaces. They were processed by gelcasting technique and compared with those prepared by semi-dry pressing process and the commercially used fusion casted ones. The effect of firing temperature (1600 °C) and the addition of 2% TiO2 on the composition and characteristics of the fired bricks were studied. The changes in phase composition and microstructure of the fired bricks were followed through X-ray diffraction analysis and scanning electron microscope. The sintering parameters, spalling resistance and corrosion against soda lime glass melt of such bricks were also determined. The results indicated that mullite, corundum and monoclinic zirconia represent the main mineral constituent of the fired bricks. The fired bricks processed by the gelcasting technique exhibited superior properties in comparison with those processed by the semi-dry pressing process. This appeared clearly in the samples consisting of 40% alumina and 60% zircon with 2% TiO2 additive. Such bricks were found to have comparable properties with the fusion-casting refractory bricks currently used in lining the basin of the electric glass melting furnaces.