A 95 V

A new alternative to α – β fused cast alumina for soda lime glass contact applications

α – β Fused cast alumina, is often used in glass contact applications (channel blocks), in place of AZS fused cast. Because of the presence of corundum (alpha alumina) phase, α – β fused cast alumina exhibits a good corrosion resistance, though not at the level of baddeleyite, against glass contact. In addition, most importantly, it does not develop a passivation layer like AZS fused cast refractory (which can cause knots and cords) and, since there is no zirconia, it cannot give specific defects like cat-scratches.

The drawback compared to AZS fused cast, is temperature, because when it rises over 1350°C, glass corrosion speed increases rapidly.

Being a fused cast refractory, α – β alumina requires a slow and expensive production process, even more complex than AZS fused cast, because of the higher melting point of the raw materials. This is reflected in the high price and long delivery times of the finished product.

Market alternatives to α – β fused cast alumina, are high alumina (> 95% Al2O3) bonded refractories; these materials are less expensive, but, due to their structure and porosity, are normally less resistant to glass corrosion and potentially capable of producing more defects.

This paper will compare A 95 V, S.I.G.MA. latest development of bonded high alumina refractory, against various α – β fused cast alumina samples, to show that the alternative is today possible.

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