摘要
Calcium aluminate cement(CAC)is a commonly used binder for refractory castables.There has been a long-running debate on the transformation mechanisms of calcium aluminate cement hydrates through solid-state reaction or solutionprecipitation.In order to demonstrate the conversion mechanism of CaO Al2O310H2O(CAH10)to 3CaO Al2O36H2O(C3AH6)and Al2O33H2O(AH3),the CAC pastes cured at 10℃to produce CAH10 was further cured at 60℃with and without free water.The hydration of the pastes was halted by freezing-drying,and the phases and microstructure of hydrates were investigated by XRD and SEM,respectively.The results indicate that CAH10 converts into C3AH6 and AH3 in water presence at 60℃,but does not transform into C3AH6 and AH3 without water,demonstrating that conversion of CAH10 into C3AH6 and AH3 does not happen through solid-state reaction,but takes place through preceding dissolution of CAH10 and subsequent precipitation of AH3 and C3AH6 from the solution.
Calcium aluminate cement（CAC）is a commonly used binder for refractory castables.There has been a long-running debate on the transformation mechanisms of calcium aluminate cement hydrates through solid-state reaction or solutionprecipitation.In order to demonstrate the conversion mechanism of CaO Al2O310H2O(CAH10)to 3CaO Al2O36H2O（C3AH6）and Al2O33H2O（AH3）,the CAC pastes cured at 10℃to produce CAH10 was further cured at 60℃with and without free water.The hydration of the pastes was halted by freezing-drying,and the phases and microstructure of hydrates were investigated by XRD and SEM,respectively.The results indicate that CAH10 converts into C3AH6 and AH3 in water presence at 60℃,but does not transform into C3AH6 and AH3 without water,demonstrating that conversion of CAH10 into C3AH6 and AH3 does not happen through solid-state reaction,but takes place through preceding dissolution of CAH10 and subsequent precipitation of AH3 and C3AH6 from the solution.
基金
the National Natural Science Foundation of China (51572244 and U1604252, 51672255) for the financial support
