Effect of Al2O3, MgO and SiO2 on Sintering and Hydration Behaviors of CaO Ceramics

Abstract

CaO ceramics were prepared by conventional sintering process and their hydration behaviors were evaluated by measuring weight increment on saturated water vapor pressure at ambient temperature. CaCO₃ and limestone were used as CaO source materials and Al2O₃, MgO and SiO₂ were added as sintering agents. Al2O₃ was a liquid phase sintering agent to increase densification and grain growth rates, whereas MgO and SiO₂, densification and grain growth inhibitors. Regardless of composition, all of the prepared CaO ceramics showed the improved hydration resistance as bulk density increased. Especially, when bulk density was more than 3.0 g/㎤, there was no weight increment after 120 h of hydration. Therefore, to decrease contact area between CaO and water vapor by increasing bulk density with the Al2O₃ sintering additive was effective for the improvement of CaO hydration resistance.