High-alumina refractory brick, that is,Refractory Bricks an aluminum silicate refractory material with an alumina content of more than 48%. It is formed and calcined from alumina or other raw materials with high alumina content. High thermal stability,Refractory Bricks refractoriness above 1770℃. Slag resistance is better. Sometimes there are black spots and black hearts on the surface of the high alumina refractory bricks received.
Causes and conditions of black cores in high alumina refractory bricks: The main impurity oxides in high alumina refractory bricks are iron oxide Fe2O3 and titanium oxide Ti2O3. It can be estimated from the reality that black core bricks become white after re-burning in an oxidizing atmosphere. The firing atmosphere and the impurity oxides of iron and titanium are the conditions for black core. However,Refractory Bricks when iron and titanium oxides coexist and exist alone,Refractory Bricks they have different effects on the color of the brick body. When titanium ions exist alone, the color is not obvious,Refractory Bricks and the high alumina brick body is slightly blue, while when iron ions exist alone, the brick body is orange-brown. However, even in an oxidizing atmosphere,Refractory Bricks the coloring and sintering of alumina can be increased to cause black cores. After three iron removal processes,Refractory Bricks efforts are made to reduce the iron content of refractory bricks.
Ways to deal with black cores in high-alumina refractory bricks: from the above,Refractory Bricks it can be seen that there are two processes for high-alumina refractory bricks to form black cores and turn white: one is the high-temperature recovery atmosphere to restore iron and titanium ions to color,Refractory Bricks and the other is at a lower temperature Low iron and titanium ions decolorize by de novo oxidation. Accordingly,Refractory Bricks the following methods can be used to prevent coloring: use strong magnetic separation to remove iron from high-titanium bauxite materials to prevent coexistence of iron and titanium ions;Refractory Bricks change the kiln location of high-alumina bricks and install them in the middle of the kiln as far as possible to prevent loading. In the vicinity of the fire box;Refractory Bricks increase the amount of hot air to form an oxygen-enriched operation to prevent the recovery atmosphere;Refractory Bricks in the cooling process,Refractory Bricks slowly lower the temperature, so that the low-priced iron and titanium ions are re-oxidized and decolorized.
