基于FactSage计算的稀土氯化物溶液直接制备稀土氧化物热力学分析  

Thermodynamic Analysis of Phase Diagrams Simulated by FactSage in Process of Rare Earth Oxides Production by Spray Pyrolysis Method

作　　者：郭小惠[1] 苏欢欢 伍永福[1,2] 吴文远 Guo Xiaohui;Su Huanhuan;Wu Yongfu;Wu Wenyuan(Inner Mongolia Key Laboratory of Coal Chemical Engineering&Comprehensive Utilization,Inner Mongolia University of Science&Technology、Baotou 014010,China;School of Metallurgy,Northeastern University,Shenyang 110819,China)

机构地区：[1]内蒙古科技大学内蒙古煤化工与煤炭综合利用重点实验室,内蒙古包头014010 [2]东北大学冶金学院,辽宁沈阳110819

出　　处：《中国稀土学报》2020年第6期788-797,共10页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(51464041);内蒙古自然科学基金项目(2018MS05009)资助。

摘　　要：稀土氯化物溶液直接热解制备稀土氧化物,由于其工艺流程短绿色环保越来越受到人们的重视,然而其化学反应过程本质分析不清制约该工艺的进一步推广。利用FactSage软件从热力学角度分析了温度和载气组成及浓度对热解反应产物的影响,建立了轻稀土氯化物水溶液经喷雾热解法生产轻稀土氧化物这一工艺过程的相图。研究发现:La,Nd,Sm和Eu氯化物发生热解反应的转变温度随原子序数的增加而降低;Ce和Pr氯化物热解过程中因发生价态变化需要有O2的参加,其反应温度低于相邻的元素;La和Nd氯化物需经氯氧化物中间产物生成氧化物,其反应温度最高。对所有喷雾热解过程,低氯化物浓度和高O2浓度(分压)都有利于氧化物的生成。对于有氯氧化物生成的LaCl3,加入双氧水H2O2对转化温度降低的作用不大,是由于软件自身的缺陷所造成的。The one-step production of rare earth oxides(REOx)from rare earth chlorides(RECl3)by spray pyrolysis method has attracted much attention due to its short,green and eco-friendly process.However,the further promotion of this process was impeded by the ambiguous understanding about the fundamental issue on its chemical reaction.Consequently,the phase diagrams of this process were simulated by FactSage software.The influences of temperature,carrier gas composition and pressure on reaction products were analyzed via thermodynamics.Through theoretical calculation,the conversion temperature of light rare earth chlorides like LaCl3,NdCl3,SmCl3 and EuCl3 decreases with the increase of atomic number.While CeCl3 and PrCl3 can convert at lower temperature compared with their adjacent elements,and it is due to the participation of O2 in the reaction.The valence states of Ce and Pr change from RE+3(in chlorides)to RE+4(in oxides)at the oxidation of O2.The formation temperature of La2O3 and Nd2O3 is higher than that of other rare earth oxides,because they are formed indirectly from LaCl3 and NdCl3 via LaOCl and NdOCl as intermediates.For all spray pyrolysis processes,lower chloride concentration and higher oxygen concentration(partial pressure)are beneficial to the formation of oxides.For LaCl3,the addition of H2O2 has little effect on the reduction of conversion temperature,which is due to the defects of the FactSage software itself.

关 键 词：喷雾热解 稀土氧化物 相图 热力学分析 FactSage软件 

分 类 号：TF845.6[冶金工程—有色金属冶金]