摘要
对碳酸铈晶体形貌调控及结晶过程机理的探究,是获得特殊形貌的二氧化铈的前提。在未添加任何模板剂的情况下,通过控制结晶过程条件,制备出不同分支形态的碳酸铈晶体。同时,集成多种过程分析技术,对关键过程参数进行实时测量,探究碳酸铈的结晶机理。研究表明,反应结晶温度、碳酸氢钠溶液浓度以及滴加速率是影响碳酸铈晶体分支形貌的主要因素。利用pH计和浊度仪实时监控反应结晶过程的pH变化和浊度信号,使用在线显微镜实时观察反应结晶过程颗粒的动态形貌变化,在结晶过程中不同时间点取样进行离线形貌表征和XRD分析,联合证明了碳酸铈的结晶过程为首先无定形成核-然后无定形溶解-最后再结晶。其中转晶过程的差异导致碳酸铈不同分支形貌晶体的形成。
Manipulation and control of crystal shape and investigation on the fundamental mechanism of cerium carbonate crystallization are the prerequisite of obtaining ceria crystal with targeted morphology.In this work cerium carbonate crystals with varied branching morphology were prepared by controlling the crystallization process without adding any templates.Process analysis technology was applied to reactive crystallization of cerium carbonate to explore the crystallization mechanism.It revealed that the branching morphology of these microcrystals has a strong dependence on the reaction conditions,especially the reaction temperature,sodium bicarbonate solution concentration and feed rate.The pH and turbidity during the reaction crystallization process were monitored by a pH meter and a turbidity meter respectively.An on-line imaging probe was also utilized to monitor the evolution of particle morphology during reactive crystallization.Samples were taken at different times during crystallization and analyzed by X-ray powder diffraction and scanning electron microscope.The data revealed that the crystallization pathway of cerium carbonate is amorphous precursors nucleation-dissolution-recrystallization.The transformation process leads to the formation of cerium carbonate crystal with different branching morphologies.
作者
李钿
张扬
王学重
LI Tian;ZHANG Yang;WANG Xue-zhong(School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510640,China;Centre for Pharmaceutical and Crystallization Process Systems Engineering,School of Chemical Engineering,Beijing Institute of Petrochemical Technology,Beijing 102617,China)
出处
《稀土》
EI
CAS
CSCD
北大核心
2020年第1期1-10,共10页
Chinese Rare Earths
基金
国家自然科学基金重大研究计划(91434126)
国家自然科学基金重点项目(61633006)
广东省应用型科技研发资金项目(2015B020232007)
广东省自然科学基金面上项目(2014A0303113228)
广东省自然科学基金项目(2017A030310262)
中央高校基本科研业务费资助项目(2017MS092).
关键词
碳酸铈
分支形貌
过程监测
溶解-再结晶
cerium carbonate
branching growth
process analysis technology
dissolution-recrystallization
