Corundum castable is a kind of high alumina refractory castable. Because of its stable high-temperature performance, good wear resistance and corrosion resistance, it is commonly used in the lining of a variety of high-temperature industrial kilns. It is an amorphous refractory prepared by mixing electric fused brown corundum as the main refractory aggregate, adding a variety of ultra-fine powder and calcium aluminate cement binder in proportion.
Corundum castables are widely used, and the quality of on-site construction is closely related to the quality of corundum castables. The following is the on-site construction instructions of corundum castables:
- Before the construction of corundum castable, three supplies and one leveling shall be achieved, and the construction equipment and construction surface must be clean and tidy.
- The temperature during construction shall be about 30 ℃, and construction shall not be carried out under the construction environment lower than 5 ℃.
- Clean drinking water with pH value of 6-8 shall be used. The amount of water added shall be accurately weighed, and the amount added shall be 4-6% of the total amount, which can be increased or decreased according to the actual situation.
- It is recommended to use a forced mixer to mix the aggregate, powder and binder of corundum castable evenly, and the mixing tools must be clean.
- Mixing sequence: mix the aggregate and powder for 3 minutes, add the specified amount of water after uniformity, and then mix evenly for 6 minutes. When discharging, ensure that the mixture has sufficient fluidity.
- The mixed corundum refractory castable must be used within 30min during pouring. The castable that has lost fluidity cannot be reused to avoid waste.
- The pouring thickness shall be based on the actual kiln lining requirements or design requirements to ensure uniform pouring and dense vibration.
- The pouring surface of all Abrasives shall be coated with a layer of engine oil in advance, and the embedded metal parts shall be painted with a layer of 2mm thick asphalt paint.
When pouring, install the mold first. After installation, pour the corundum castable into the mold and put it into use after curing, drying and demoulding.
The construction steps of corundum castable are roughly the same as those of other refractory castables. The pouring construction of castable is also a major factor affecting the service life of refractory castable, so the on-site construction process is also very important.