ZnC₂O₄·2H₂O-MgC₂O₄·2H₂O在空气中的热分解动力学

ZnC 2 O 4 ·2H 2 O-MgC 2 O 4 ·2H 2 O在空气中的热分解动力学 Kinetics of the Thermal Decomposition of ZnC 2 O 4 ·2H 2 O- MgC 2 O 4 ·2H 2 O Mixture in Air 林传明 LIN Chuan-ming 1 2 first-author 陈栋华 CHEN Dong-hua 1 2 中南民族大学化学与材料科学学院/催化材料科学湖北省重点实验室 中南民族大学化学与材料科学学院/催化材料科学湖北省重点实验室 College of Chemistry and Material Science/Hubei Key Laboratory for Catalysis and Material Science, South-Central University for Nationalities College of Chemistry and Material Science/Hubei Key Laboratory for Catalysis and Material Science, South-Central University for Nationalities 中南民族大学化学与材料科学学院/催化材料科学湖北省重点实验室,湖北,武汉,430074 中南民族大学化学与材料科学学院/催化材料科学湖北省重点实验室,湖北,武汉,430074 通过热重微分热重法（TG DTG）、差示扫描量热法（DSC）、X 射线衍射（XRD）技术研究了固态物质ZnC2O4·2H2O MgC2O4·2H2O机械混合物（摩尔比3∶1）在空气中热分解的过程.TG DTG的曲线表明,其热分解过程TG曲线中4个明显的台阶与理论失重相吻合;XRD结果表明样品在800 ℃煅烧时有较好晶型的MgxZn1-xO的生成.同时,用Ozawa法和Kissinger Akahira Sunose （KAS）法求取活化能Ea,用热分解动力学机理函数求算的比较法判断出可能的机理函数.ZnC2 O4 热分解的活化能分别为151.08 kJ/mol （Ozawa法）、147.73 kJ/mol（KAS法）,MgC2O4热分解的活化能分别为164.17 kJ/mol（Ozawa法）、159.94kJ/mol（KAS法）;ZnC2O4和MgC2O4热分解反应过程都遵循随机成核和随后生长型机理函数Am（Avrami Erofeer）. The thermal decomposition processes taking place in the solid state oxalate mixture of ZnC 2 O 4 ·2H 2 O-MgC 2 O 4 ·2H 2 O （3∶1 mole ratios） have been studied in air using TG-DTG（thermogravimetry-derivative thermogravimetry）, DSC（differential scanning calorimetry） and XRD（X-ray diffraction） techniques. The results of TG-DTG curves showed that, the decomposition proceeded through four well-defined steps with TG curves closely corresponded to the theoretical mass loss. The decomposition behaviour of the oxalate mixture was in good agreement with that of the individual oxalates. The result of XRD showed that the product was mostly the mixture of ZnO and MgO when the sample calcined at 550 ℃ for one hour, and it indicated the poorly crystalline structure which MgO was obtained at this decomposition stage. The well-crystallized Mg x Zn 1-x O formed in the sample calcined at 800 ℃ for two hours. The activation energies were calculated through the Ozawa and Kissinger-Akahira-Sunose （KAS） methods, and the possible conversion functions had been estimated through the comparative method. The two kinds of activation energies for the decomposition of ZnC 2 O 4 were 151.08 kJ/mol （Ozawa method） and 147.73 kJ/mol （KAS method）. And two kinds of the activation energies for the decomposition of MgC 2 O 4 were 164.17 kJ/mol （Ozawa method） and 159.94 kJ/mol （KAS method）. The possible conversion functions for the （decomposition） of ZnC 2 O 4 and MgC 2 O 4 kept to the conversion function of Nucleation and Growth,（respectively.） MgC2O4·2H2O ZnC2O4·2H2O 热重微分热重法 差示扫描量热法 X射线衍射 热分解动力学 MgC2O4·2H2O ZnC2O4·2H2O TG-DTG（thermogravimetry-derivative thermogravimetry） DSC（differential scanning calorimetry） XRD（X-ray diffraction） thermal analysis kinetics O611 湖北省自然科学基金重点资助项目（2001ABA009） 2005-02-01 2021-04-01 2