The cooling zone is for cooling the glass liquid evenly to the molding temperature. Its structure is similar to that of the melting zone, but the requirement for refractory materials is different.
In the cooling zone, the temperature is lower and the corrosion is not so severe as that of the melting zone. The glass liquid is withdrawn from the tank at the outer end of this zone to the molding zone. Refractory materials used in this zone are required not to contaminate the glass liquid.
As fused cast alumina block ?-? does not contain ZrO2, it is not stable at high temperature. However, as it contains only 1-2% glass phase, it has better corrosion resistance than fused cast AZS block under 1350?, so it is the ideal refractory material for the cooling zone. Fused cast AZS block 33# is also used in this zone. Other refractory materials used include ?-? Al2O3 ramming mass and silica brick.
Fused cast alumina block ?-?, fused cast AZS block 33# and ?-? Al2O3 ramming mass barely produce any blistering or stones and cause no contamination to glass liquid. They are usually used in glass contact areas and other demanding areas.
Fused cast alumina block ?-? is generally used in the sidewall and paving block of the refining zone and cooling zone. Under the paving block, ?-? Al2O3 ramming mass is used. Then under the two layer, a layer of large fireclay bricks are used.
Fused cast AZS block 33# is used in the glass contact part of the sidewall. The breast wall, the part of sidewall that is not in direct contact with glass liquid, always employs fused cast alumina block ?-?.
Except those demanding areas, other parts (crown, suspended wall, channel, etc.)always use silica bricks.
The cooling zone generally achieves the cooling of glass liquid by radiating the heat through its surface, so insulating materials are always not used in this zone except the channel and the tank bottom.