Calcination Kinetics of α-Al2O3 by Multiple Scanning Method
With aluminum hydroxide powder as raw material,aluminum hydroxide was roasted into α-Al2 O3,and the phase transformation and microstructure change during the process were investigated.Then,the kinetics of the calcination process was calculated by simulation with multiple scanning method.It is found that the optimum conditions for aluminum hydroxide calcinated into α-Al2O3 are as follows:calcination temperature of 1200℃,time of 2 h,heating rate of 5℃/min.Three endothermic peaks can be observed during the calcination process of aluminum hydroxide,corresponding to three weightlessness stages.In the first stage of reaction,the function of mechanism is G(α)=[(1-α)-1/3-1]2,the average activation energy is 91.16 kJ/mol and the pre-exponential factor is between 17.00×109 and 44.03×109 min-1.In the second stage of reaction,the function of mechanism is G(α)=α2,the average activation energy is 106.2 kJ/mol and the pre-exponential factor is between 7.70×109 min-1 and 18.60×109 min-1.In the third stage of reaction,the function of mechanism is G(α)=α1/4,the average activation energy is 235.42 kJ/mol,and the pre-exponential factor is between 39.94×109 and 50.79×109 min-1.
NETL
NSTL
万方数据
