Non-isothermal kinetic analysis of thermal dehydration of La_2(CO_3)_3·3.4H_2O in air  

La_2(CO_3)_3·3.4H_2O在空气中热脱水的非等温动力学分析(英文)

作　　者：张湘辉[1] 何川[2] 汪灵[1] 刘菁[1] 邓苗[1] 冯谦 

机构地区：[1]成都理工大学 材料与化学化工学院,成都610059 [2]中南大学 机电工程学院,长沙410012 [3]德国耐驰仪器制造有限公司 成都办事处,成都610017

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第10期3378-3385,共8页中国有色金属学报（英文版）

基　　金：Project(201011005-5)supported by the National Land and Resources Public Welfare Scientific Research Project of China;Project(41030426)supported by the National Natural Science Foundation of China;Project(20095122110015)supported by Specialized Research Fund for the Doctoral Program of Higher Education of China;Project(2010-32)supported by Scientific Research Foundation of the Education Ministry for Returned Chinese Scholars,China

摘　　要：The single phase La2（CO3）3·3.4H2 O 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.采用水热法合成单相La2（C O 3）3·3.4 H2O。采用XRD、FTIR以及DTA-T G对La2（C O 3）3·3.4 H2 O在3 0~1 0 0 0°C的热分解过程、中间及最终产物进行表征。在非等温条件下对L a2（C O3）3·3.4H2O在3 0~3 6 6°C范围内的热脱水动力学进行研究。采用Flynn-Wall-Ozawa及Friedman等转化法计算其反应活化能并对其反应阶段进行分析。采用多元非线性回归程序确定其最可能的反应机理及动力学参数。结果表明,L a2（C O3）3·3.4H 2O的热脱水为三步竞争反应,一个n序列初始反应后为n序列竞争反应（F nF nF n机理）。经最可能的反应机理计算所得的活化能与Friedman等转化法的计算结果非常接近,拟合后的TG及DTG曲线与原始曲线能较好地吻合。

关 键 词：La2（CO3）3·3.4H2O non-isothermal kinetics simultaneous thermal analysis dehydration reaction 

分 类 号：O643.1[理学—物理化学]