Abstract
Calcium zirconium aluminate, Ca7ZrAl6O18, is only the ternary compound of CaO, Al2O3 and ZrO2 with hydration reactivity. Calcium zirconium aluminate is conventionally synthesized by a solid-state reaction processing using CaCO3, Al2O3 and ZrO2, as starting materials at temperatures exceeding 1400 °C. In the present study, Ca7ZrAl6O18 along with some admixture phases was prepared by modifying co-precipitation method using ammonia solution, NH3(aq) or saturated oxalate ammonium solution in concentrated ammonia solution, (NH4)2C2O4–NH3(aq) as a precipitation agent. Crystalline Ca7ZrAl6O18 phase was detected at relatively low temperature (~900 °C) together with other intermediate crystalline products. Formation of the final product of Ca7ZrAl6O18 powders, with CaZrO3 and Ca12Al14O33 as accessory phases, requires heat treatment at 1200 °C for 5 h. Two novel approaches for the synthesis of Ca7ZrAl6O18 affect its further hydration behaviour. Ca3 [Al(OH)6]2 or C3AH6 with a hitherto unknown rounded crystal habit was formed within the cement pastes made of Ca7ZrAl6O18, which was synthesized by the modifying co-precipitation method using (NH4)2C2O4–NH3(aq) as a precipitation agent.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call