| abstract |
A high zirconia electrically fused cast refractory having long time durability with less cracking during production and in the course of temperature rising, excellent in productivity, less forming zircon crystals in the refractory itself and even in contact with molten glass, excellent in bubble foamability to molten glass, less generating cracks even undergoing heat cycles during operation of a glass melting furnace. A high zirconia electrically fused cast refractory comprises, as chemical component, 85 to 95% by weight of ZrO2, 0.4 to 2.5% by weight of Al2O3, 3.5 to 10.0% by weight of SiO2, 0.05% by weight or more of Na2O, 0.05 to 0.7% by weight of Na2O and K2O in total, 0.01 to 0.04% by weight of B2O3, 0.1 to 3.0% by weight of SrO or BaO when one of BaO and SrO is contained, 0.1% by weight or more of SrO and 0.1 to 3.0% by weight of SrO and BaO in total when both of BaO and SrO are contained, 0.01 to 0.2% by weight of CaO, 0.1% by weight or less of MgO, 0.01 to 0.7% by weight of SnO2, 0.3% by weight or less of Fe2O3 and TiO2 in total, less than 0.01% by weight of P2O5, and less than 0.01% by weight of CuO. |