The alkaline, acidic and chlorine content components in the alkaline atmosphere will penetrate deeply into the high alumina brick. The service life is short, so high alumina fire bricks should not be used as linings in alkaline atmospheres.
1. Alkaline atmosphere erosion will cause cracks in high alumina bricks
The erosion of the alkaline atmosphere will cause multiple transverse cracks in the high alumina refractory bricks, and loose foam will appear on the surface of the high alumina firebricks to a thickness of 0-10mm. It will also cause the bricks to expand and alkaline components to be deposited on the upper surface of the high alumina fire bricks. The hot side of high alumina refractory bricks, that is, the use side, will be more severely corroded than the cold side. If the use surface is seriously eroded, the service life of the high alumina brick will be shortened.
Moreover, the silica content in high alumina bricks is higher than that in alkaline bricks. The higher the silicon content, the greater the amount of liquid phase generated, making it less suitable for use in alkaline atmosphere linings. Excessive liquid phase deforms the bricks and reduces their strength. The presence of free silica in bricks puts the bricks at greater risk of damage.
Once the free silica in the high alumina brick is exhausted, the intrinsic crystalline phase will be more severely eroded. At the same time, the thenardite and mullite in the bricks will react directly to form chert, which will further cause destructive expansion. Using high alumina fire bricks in alkaline atmosphere linings may cause the furnace lining to suddenly collapse.
2. High alumina bricks are neutral media
High alumina refractory bricks are refractory shaped products belonging to neutral medium and are generally used in neutral atmosphere. If used in an alkaline atmosphere, alkali erosion will cause the lining of the brick to expand and reduce its strength. When various indicators are reduced, the internal changes of the brick will occur. After the internal changes, the brick lining will peel off or even peel off. This will cause the lining to collapse suddenly, causing the furnace lining to be unable to be used normally.
Therefore, do not use high alumina bricks for lining in alkaline corrosive atmosphere. The selection of alkaline refractory bricks is consistent with the alkaline atmosphere, the atmosphere is unified, and the alkaline-resistant refractory bricks have a long service life, reducing the frequency of lining changes and reducing production investment.
