Fused cast AZS block is also called fusion cast AZS block and fused cast Al2O3-ZrO2-SiO2 block. AZS is the abbreviation of Al2O3, ZrO2 and SiO2. Fused cast AZS block is composed of 50%-70% Al2O3, 20%-40% ZrO2 and a small amount of SiO2 and other components. Based on the ZrO2 content, it can be divided into AZS 33#, AZS36# and AZS 41#. The most commonly used is AZS 33#, which has a density of 3.1-3.4g/cm3 and maximum service temperature of 1700 degree. Based on the position of the electrode, the melting methods of fused cast AZS can be classified into the reducing method and the oxidizing method. The electrode of the reducing method is inserted into the melt, while the electrode of the oxidizing method is over the liquid level. Products made by different methods have different mineral composition as well as different proportions and different content of reducing substances (C, H) . All these will affect the exudation temperature exudation amount of glass phase. Now most manufacturers adopt the oxidizing method, since it can reduce the carbon content to 0.003%-0.006% by long arc melting and blowing oxygen to the melt. Compared to the reducing method, it can produce fused cast AZS block with higher corrosion resistance to molten glass and higher exudation temperature.