What role does refractory aggregate play in refractory castables?

Refractory aggregate and matrix material
The mass ratio of refractory aggregate to matrix material is to use different kinds of refractory aggregates to make refractory castables under the same matrix composition. The mass ratio of matrix material to aggregate is generally 7:3, among which is super The volume density of bauxite clinker is relatively small, the particles are angular, and the pores are relatively large, so the water demand is relatively large when mixing.
White corundum
After talking about the special grade bauxite, let’s talk about white corundum. White corundum is a very good aggregate. Its bulk density is not too large, but its water absorption rate is relatively large, and its particles have more edges and corners, so stir The water consumption is larger than that of alumina.
Coarse aggregate
Before this, it was said that adding coarse aggregates to the refractory castable greatly improved the anti-flaking performance and thermal shock resistance of the refractory castable. Then we did an experiment and found that adding coarse bones to the castable After filling, the shape of the cracks shifted and branched, which restrained the long cracks and changed the direction, organized the propagation of cracks in the matrix, and improved the spalling resistance and thermal shock resistance of the castable.
However, if too much coarse aggregate is added to the castable, it will have a counterproductive effect. Too much will reduce the anti-stripping performance of the castable and affect the normal use of the castable. Therefore, it must be appropriate when adding coarse aggregate. Not too much.
Refractory aggregate
Refractory aggregate is an indispensable raw material for refractory castables. It affects the physical mechanics and high-temperature performance of the castable. Therefore, when using it, it must be reasonable according to the actual use and the technical formula given by the castable manufacturer. The choice of refractory aggregate varieties, critical particle size and particle gradation.