Castable refractories is composed of refractory cement and refractory aggregate, so cement is also playing an important role in refractory castable, low apparent porosity, high refractoriness, high softening temperature under load, high temperature strength, good thermal shock stability.However, if the cement dosage is not well controlled, it will also cause the deterioration of refractory castable performance.
1, in order to complete hydration of cement, excessive addition of water (10%~15%) during mixing results in high apparent porosity of ceramic castable refractories, resulting in decreased density.
2. Calcium aluminate hydrate has a strong effect of dehydration and recrystallization in the medium temperature stage, which destroys the structure of hard point in the castable and makes the strength of refractory castable drop sharply in the medium temperature stage.
3, cement binder will bring more calcium into the castable, leading to the decline of the load softening temperature of ceramic refractory castable, thermal shock stability index deterioration.
Therefore, according to the situation, to control the amount of cement, can significantly improve the service life of refractory castable.