What is a low cement castable?

Low cement refractory castable refers to the refractory castable combined with calcium aluminate cement, the content of CaO is less than 2.5%, that is, the amount of calcium aluminate cement added is about 1/2 of the ordinary calcium aluminate cement castable. 1/3 of the castable. Castables with Cao content generally between 1.0 and 2.5% are called low-cement castables. The castable with Cao content less than 10% is called ultra-low cement castable.

The difference between it and ordinary refractory castables is that in the matrix of low cement and ultra-low cement, ultrafine powder (particle size less than 1m) with the same or similar chemical composition as the main material of the castable is used to replace part or most of the calcium aluminate cement. , At the same time adding a small amount of dispersant (water reducing agent) and a certain amount of deactivation accelerator, the low-cement and low cement castables  LLC have the following advantages:

(1) The lower content of CaO in the castable can reduce the eutectic phase generated in the material, thereby improving the refractoriness, high temperature strength and slag resistance

(2) The water requirement of the castable is only 1/2~1/3 of the ordinary refractory castable, so the porosity is low and the bulk density is high;

(3) There are few cement hydrates generated after molding and curing, and there is no problem that a large number of hydration bonds are destroyed during heating and baking, which reduces the strength at medium temperature, but gradually sinters with the increase of heat treatment temperature, and the strength also gradually increases.