Use of Fused Cast AZS Refractories in Glass Industry

Fused Cast AZS refractories are also called fused cast refractory which is abbreviated as AZS because it contains Al2O3－ZrO2－SiO2. They are a good alternative in refractory materials for the glass industry because they can withstand the aggressive conditions during liquid processing of glass. 

The term Fused Cast refers to a manufacturing process in which the ceramic bonding is obtained by the solidification of a mixture which has been melted in an electric furnace and cast in liquid state into molds. AZS refractory is made from pure alumina powder and Zircon sand. 

The glass industry has serious problems of contamination because during the initial melting glass, the refractory brick can be attacked in the most vulnerable points as in the matrix that surrounds the gross particles. The dissolution process of the matrix frees the gross particles and they remain floating in the glass, passing subsequently to the final product. AZS refractories can avoid this is problem well due to their good erosion resistibility to molten glass. 

Fused Cast AZS Refractories are the most widely used materials in glass melting furnaces. They can be classified by their zirconia content, which basically defines their corrosion resistance, into 3 types: AZS-33#, AZS-36# and AZS-41#.  

The compact microstructure of AZS-33# enables it to have very good corrosion resistance to molten glass. It very rearely results in stoning and has very limited chances to cause blistering and othe defects to glass, so it is the most common product used in the glass furnace for superstructure, working pool side wall, paving blocks, feeder channels, tank bottoms, C-shaped block and doghouse crown,etc.
Despite of the similar eutectic crystal as AZS-33#, it has more free baddeleyite crystals in chain structure and less vitreous phase, which further improve the corrosion resistibility and reduce the potential defects in glass, so it is recommended to be used in sections where glass flow is faster and temperature is higher, such as melter sidewall, paving, front wall, back wall, top crown, doghouse, and superstructures in glass melting furnace.