The non-isothermal kinetics of mullite formation from both non-mixed and mixed with different rare earth oxides（Pr6O11 and Er2O3） kaolinite were studied by comprehensive thermal analysis technologies and X-ray diffr...The non-isothermal kinetics of mullite formation from both non-mixed and mixed with different rare earth oxides（Pr6O11 and Er2O3） kaolinite were studied by comprehensive thermal analysis technologies and X-ray diffraction（XRD）. Meanwhile, Kissinger equation, Ozawa equation and JMA modified equation（I） and（II） were employed for analysis of the effects of Pr6O11 and Er2O3 on the kinetics of kaolinite in phase transformation at high temperatures. The results showed that the addition of two kinds of rare earth oxides influenced the crystallization kinetic parameters of kaolinite. Crystallization activation energies and frequency factors of the kaolinite mixed with Pr6O11 were obviously decreased compared with the kaolinite with none, but the kaolinite mixed with Er2O3 weakly decreased. Crystallization behaviors were not changed, belonging to volume crystallization. Mullite formation from kaolinite was suppressed while generation of cristobalite was promoted by Pr6O11, and effect of Er2O3 on mullite formation from kaolinite under high temperature was not evident.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(51264009)the Natural Science Foundation of Jiangxi Province of China(20122BAB206023)
文摘The non-isothermal kinetics of mullite formation from both non-mixed and mixed with different rare earth oxides（Pr6O11 and Er2O3） kaolinite were studied by comprehensive thermal analysis technologies and X-ray diffraction（XRD）. Meanwhile, Kissinger equation, Ozawa equation and JMA modified equation（I） and（II） were employed for analysis of the effects of Pr6O11 and Er2O3 on the kinetics of kaolinite in phase transformation at high temperatures. The results showed that the addition of two kinds of rare earth oxides influenced the crystallization kinetic parameters of kaolinite. Crystallization activation energies and frequency factors of the kaolinite mixed with Pr6O11 were obviously decreased compared with the kaolinite with none, but the kaolinite mixed with Er2O3 weakly decreased. Crystallization behaviors were not changed, belonging to volume crystallization. Mullite formation from kaolinite was suppressed while generation of cristobalite was promoted by Pr6O11, and effect of Er2O3 on mullite formation from kaolinite under high temperature was not evident.
