Alkaline refractory castable needs to be solved

The results of practical and experimental studies on the development of alkaline refractory castable show that a complete alkaline refractory castable needs to solve the following problems:

(1) Sufficient available time.

(2) The alkaline fine powder does not hydrate during drying.

(3) Good volume stability in the case of multiple thermal cycles.

(4) Less slag penetration during use.

(5) No structural spalling occurs when in contact with basic ferrite (iron-containing oxide slag). Alkaline refractory castable, because it is easy to dissolve Ca2+ and Mg2+ from the main raw material, they will condense the highly dispersed active substances such as uf-Al2O3 and uf-SiO2, resulting in too fast hardening rate, short service time, and difficult to obtain dense construction (casting) body. The solution is to select a better integrator to seal these cations to control the condensation rate of the active substance in the dispersed state, so as to obtain a dense construction (pouring) body.

Another problem with the existence of alkaline refractory castables is the possibility of cracking during the drying process to destroy the construction (casting) body, because MgO produces hydration during the drying process. Because the dissolution reaction of MgO in water and the direct hydration reaction of water vapor will lead to the structural damage of alkaline refractory construction body. As an important measure to improve the hydration resistance of alkaline refractory castables, the correct selection of additives is usually recommended (uf-SiO2, that is, active SiO2 ultrafine powder). Another benefit of adding uf-SiO2 to basic refractory castable is that it reduces the infiltration of molten slag into the basic refractory castable.