Design, characterization, and incorporation of geopolymer binders in refractory ceramic compositions

Abstract The development of cement‐free refractories has gained attention in recent years. Geopolymers (GP) are cold‐setting binders that may be applied in the manufacturing of such ceramics. However, a systemic comparison between calcium aluminate cement (CAC) and GP‐bonded formulations is still necessary to understand the strengths and limitations of these novel binders. In this study, three GP were designed and characterized, and the most promising composition was incorporated into an alumina refractory. A corresponding CAC‐containing formulation was also evaluated as a reference material. The physico‐mechanical properties of the prepared ceramics were analyzed after heat treatments ranging from 40–1250°C. Among the designed GP, the sodium‐containing binder showed the best performance, although its addition to alumina refractory resulted in cured samples with low mechanical strength. However, with the progression of liquid formation, sintering, and densification during firing at 1100–1250°C, the GP‐bonded refractory displayed enhanced flexural strength, surpassing the performance of the CAC‐containing composition.