Fused Cast AZS Exudation And Glass Defects

Fused cast AZS block is the most widely used refractory material in the demanding areas. It is thought as the leading cause of knot and cord defects. Fused cast AZS exudation in glass contact is the main cause of impaired performance of AZS under particular working conditions.
The main crystal phase of Fused cast AZS consists of corundum, baddeleyite and glass phase. The glass phase can reduce the expansion or shrinkage of ZrO2 within the above temperature range and prevent cracking. However, the glass phase is easy to be corroded and cause corrosion of the fused cast AZS and glass defects.
Fused cast AZS exudation exhibits a shiny "wet looking" appearance at the surface of blocks during heat-up process and beginning of a furnace campaign. This situation tends to stabilize all along the campaign life, with a generally moderate dripping of a viscous glassy phase into the smelted glass.
Fused cast AZS exudation at high temperatures, can lead to the formation of defects in the glass, especially during furnace start-up. It is only a short-term cause of glass defects. Fused cast AZS exudation from a glass contact surface is not very visible than that in the superstructure.
In the glass furnaces, a portion of the glass phase of fused cast AZS block exudes onto the superstructure surface during furnace heat-up, until the furnace has achieved stable temperature profile. The exuded glass, often containing small zirconia crystals, tends to run down into the glass bath. This is a major concern to glass producers since this glassy phase often causes defects, such as viscous knots and stones.
To solve this problem, low exudation fused cast AZS has been developed. With modification of chemical compositions and glass phase, it offers low exudation level and maintains all other positive characteristics of fused cast AZS.
Sunrise offers various refractory materials for glass furnaces including fused cast AZS, silica brick, fireclay brick, high alumina brick, silimanite brick, mullite brick, etc..
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