中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 10 October 2014 |
（1. College of Materials and Chemistry and Chemical Engineering,
Chengdu University of Technology, Chengdu 610059, China;
2. College of Mechanical and Electrical Engineering, Central South University, Changsha 410012, China;
3. NETZSCH Scientific Instrument Trading Co., Ltd., Chengdu Branch, Chengdu 610017, China）
Abstract:The single phase La2(CO3)3·3.4H2O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2(CO3)3·3.4H2O from 30 to 1000 °C were characterized by XRD, FTIR and DTA-TG. The kinetics of dehydration of La2(CO3)3·3.4H2O in the temperature range of 30-366 °C was investigated under non-isothermal conditions. Flynn-Wall-Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La2(CO3)3·3.4H2O is a kind of three-step competitive reaction, and controlled by an n-order initial reaction followed by n-order competitive reaction (FnFnFn model). The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG-DTG curves very well.
Key words: La2(CO3)3·3.4H2O; non-isothermal kinetics; simultaneous thermal analysis; dehydration reaction
