Magnesia hydration is an important concern when it is added to refractory castables. The volumetric expansion that follows this reaction can cause the material’s breakdown. Recent reports in literature suggest that if this reaction could be halted or slowed down, significant benefits in castables properties would be attained. In this work, microsilica addition was employed as a magnesia anti-hydration technique (MAHT). Using apparent volumetric expansion (AVE) and mechanical strength measurements, the drying behavior and X-ray diffraction, an anti-hydration mechanism based on the generation of protective magnesium silicate coating is proposed. Its limitations and effects upon castables processing were also evaluated.
magnesia; hydration; microsilica; refractory castables
