What are the differences between corundum bricks and chrome corundum bricks?
Corundum bricks are made of alumina as the main raw material. Refractory bricks with a content of more than 90% can be called corundum refractory bricks, but It also have different contents. Pure corundum and high alumina bricks are refractory bricks with a certain proportion of corundum; chrome Corundum bricks are made by adding different proportions of Cr2O3 to raw materials with high aluminum content. Their raw material ingredients are different.
However, the production of these two types of bricks is basically the same. They must be formed by high pressure and sintered at high temperature. However, the sintering temperature is slightly different, and the temperature of chrome corundum bricks will be about 20°C higher. However, if the chromium corundum firebricks used at the bottom of the glass kiln are cast, the price will be several times higher than that of sintered corundum refractory bricks. Even if the two bricks are made by the same sintering method, the price of chrome corundum brick is relatively higher than that of corundum brick.
1. Temperature and intensity are different
The service temperature of corundum bricks is around 1600℃; the service temperature of chrome corundum bricks is around 1700℃, and the load softening temperature is also different. Corundum firebricks are at 1600℃, and chrome corundum fire bricks are ≥1700℃. The service temperature of chrome corundum firebricks is better than that of corundum fire bricks.
The highest compressive strength of corundum refractory brick is about 100MPa, the normal temperature compressive strength of chromium corundum is about 120MPa, and the compressive strength of chrome corundum brick is also obviously higher than that of corundum fire brick.
2. Different thermal shock stability
As the Cr2O3 content increases, the thermal shock stability of chromium corundum fire bricks decreases. The thermal shock stability of chromium corundum firebricks with lower Cr2O3 content is better than bricks with higher Cr2O3 content. Generally speaking, the Cr2O3 content of chromium corundum refractory bricks is between 12% and 20%; especially AKZ type chromium corundum fire bricks, the thermal shock stability will be improved by adding a small amount of additives that produce phase changes. However, the thermal shock stability of corundum bricks is not as good as that of chrome corundum bricks. To adjust thermal shock stability, a certain proportion of silicon carbide must be added.
3. Different resistance to slag erosion
Corundum refractory bricks are not as resistant to slag erosion as chrome corundum bricks. When corundum bricks are severely eroded by molten slag, the slag will penetrate into the bricks and penetrate to the surface along the pores inside the bricks; chrome corundum firebricks are almost not corroded by molten slag. The edge of the inner hole is clearly demarcated from the residue and rarely penetrates into the brick. However, at lower temperatures, the slag resistance of corundum fire bricks is also acceptable. This depends on the furnace type and furnace lining used, and is determined by the temperature and degree of corrosion.
4. Different usage situations:
Chrome corundum bricks are used in glass kiln bottoms, garbage incinerators, gasifier linings, etc. Corundum bricks are used in cracking and reforming furnaces in the petrochemical and fertilizer industries, and steelmaking furnaces and blast furnaces in the metallurgical industry. Corundum refractory bricks are cheaper than chromium corundum fire bricks. When the temperature is suitable, in order to reduce production costs, it is also a reasonable choice to choose corundum firebricks.
The difference between corundum refractory bricks and chrome corundum bricks makes them play different roles in different environments and process requirements. Choosing the right materials can increase the longevity and effectiveness of your equipment. To reduce costs, when choosing which brick to use, the characteristics and differences between corundum bricks and chrome corundum firebricks should be taken into consideration to meet the furnace lining needs.
