The Use of Refractory Materials in the E Glass Unit Kiln

The corrosion of refractory materials may lead to the shutdown of unite kilns. The selection of refractory materials for the unit kiln should be based on the quality of the glass melting and the service life of the unit kiln. 

Refractory materials are subjected to high temperature, thermal shock and physical and chemical attack and mechanical scouring action of flame, powder and molten glass. Over time, refractory materials will gradually be peeled off, melt into the molten glass and cause defects such as bubbles, stripes and stones. In serious cases, it may make the drawing operation difficult. 

 

The main refractory materials used in the unit kiln include:

1) Dense chrome brick

It has excellent corrosion resistance to E glass at high temperature and does not pollute glass liquid, so it has been the preferred choice in the unit kiln of E glass. 

 

Dense chrome brick is made by isostatic molding. It has high density. It has a high content of Cr2O3 (>94%), low porosity (<15%) and high bulk density (>4.24g/cm3). Its corrosion loss is 1/10 of dense zircon brick. It is used in the sidewall and bottom of the melting zone and sidewall of the main channel and the transition channel in the unit kiln of E glass. 

 

2) Dense zircon brick

It is used in the bottom of the melting zone, the transition channel and forming channel, flow tank of the forming channel and brushing lining. Besides, it is also used as the back lining brick of the dense chrome brick. It has high temperature resistance, but its corrosion resistance to glass liquid is as good as dense chrome brick. It is made by isostatic molding. It has high content of ZrO2 (>65%), low porosity (<2%) and bulk density (4.25g/cm3). when the temperature of the E glass unit kiln is over 1370℃, it begins to be corroded. 

 

3) Standard zircon brick

It is used in the breast wall and back wall of the feeding port, observation hole, breast wall of the flame space, the top cover brick and the burner brick. It contains 66% ZrO2 and has a high bulk density of 3.7g/cm3. It has good thermal stability and spalling resistance. 

 

4) Sintered mullite brick

It is mainly composed of Al2O3 (>74%) and SiO2 (22.2%). Its bulk density is about 2.5g/cm3. It is mainly used in the back lining of standard zircon brick, the breast wall and front wall of the melting zone, the inner lining of the channel and fuel, the crown feet, the outer brick of the discharge opening and exterior wall of the fuel inlet of the heat exchanger. 

 

5) Fused cast AZS

It is composed of ZrO2 (34%), Al2O3 (49.2%) and SiO2 (15.9%). It has a bulk density of 3.85g/cm3. It is mainly used in the burner brick and feeding port brick of the melting zone. 

 

6) Fused cast ACS

It is composed of Cr2O3 (28.3%), Al2O3 (58.3%) and MgO and Fe2O3 (5.2%). It has a bulk density of 3.4g/cm3. It is mainly used as the flue interfaces brick in the inlet of the heat exchanger.