Generally for soda-lime-silica glass, AZS 36# is used in the upper part of the sidewall of the middle or rear melting zone. When the electric boosting and bubbling are used, the electrode brick and the bubbling brick are seriously corroded and the electrode brick is required to have good electrical insulation, so AZS 41# block is used. In this case, fused cast mullite block cannot be used in the lower part of the sidewall, because the electric boosting and bubbling technology will strongly corrode the lower part of the sidewall. When melting Fe2O3, CoO and C colored glass without the electric boosting and bubbling technology, fused cast mullite block can be used in the lower part of the sidewall. 

 

In the horizontal direction, the front, middle and back parts are subjected to different corrosion conditions. The feed port and the middle part of the furnace are the most susceptible to damage. Next is the back sidewall. The fused cast AZS sidewall near the throat is lightly damaged. However, in the dual-chamber melting furnace, there is an aliform wall near the throat. Refractory bricks here are easy to be damaged. 

 

In the vertical direction from top to bottom, the upper layer of molten glass, due to high temperatures, strong flow and intense chemical reaction, it is eroded severely. Especially the liquid level is in the junction of gas, liquid and solid phase. There is the erosion by glass water and powder material. Therefore, it is one of the weakest points in the glass furnaces. 

 

For other types of glass such as glass containing K2O, Li2O, MgO, BaO, PbO, A12O3, B2O3 and F, with a few exceptions, the sidewall bricks can be selected as described above. The exception is the high silicon low alkali or alkali-free glass. For the high silicon low alkali or alkali-free glass furnaces, quartz brick and white foam brick are used in the sidewall. Dense zircon brick and AZS 36# are also used here in foreign countries and dense zircon brick has better corrosion resistance than the AZS 36#.