Refractory castables will pulverize, mainly because the binding agents refractory cement and silica powder will pulverize if they appear for too long. The aggregates and powder in refractories castables will not pulverize.
1. Excessive cement dosage is more likely to cause pulverization.
Since refractory cement will pulverize, castable manufacturers store the granules and powder with good raw material ratio separately. If the refractory cement reaches a certain time, only the binder will be replaced, otherwise all the ingredients in the entire castable ratio will be lost. Out of service.
Generally, during use, the self-pulverization of the castable is caused by the reaction of calcium aluminate cement hydration, which causes the material to peel off when touched by hand during the drying process, or the more it is touched by hand, the more it will peel off. Many phenomena.
Another phenomenon is that self-pulverization of refractory castables will occur in high-temperature and high-humidity environments, especially lightweight castables. This phenomenon is more likely to occur in heavy castables with too much cement than in heavy castables with a small amount of refractory cement. Chalk.
2. After the construction of refractory castables is completed
After the construction of the refractories castable as lining is completed, if self-pulverization is found during the maintenance period, it must not be put into use again. Otherwise, the surface of the lining will be affected in the mild case, and the entire kiln will not be able to be used normally in severe cases.
3. Under what circumstances is magnesia castable most likely to pulverize?
If it is an amorphous castable that combines phosphoric acid and water glass, there will be no self-powdering phenomenon. Magnesia castables can also self-powder. Magnesia castables are most likely to pulverize, especially when water is added and high temperature and humidity occur.
Therefore, hydraulic castables cannot be constructed when they are too wet. In addition, the production date must be accurate before construction. If the castable has been left for more than 6 months, the binder must be replaced. Otherwise, unexpected serious consequences may occur.
In short, no matter what kind of refractory castable it is, it must be carefully used at the correct time, so that the material can achieve good use effects.
