锌离子路易斯酸熔盐体系从粗四氯化锆中除铝机制研究

Research on Aluminum Removal Mechanism from Crude Zirconium Tetrachloride by Zinc-Ion Lewis Acid Molten Salt System

为了降低传统沸腾氯化法制备的粗ZrCl_(4)中Al杂质含量,达到高品质锆前驱体的精度要求,开发了适合粗ZrCl_(4)高效除Al的锌离子路易斯酸熔盐体系,使其中的杂质Al含量由0.16%降低至0.001%。同时,根据路易斯酸熔盐体系与粗ZrCl_(4)中Al^(3+)的反应,通过基于密度泛函理论的CASTEP模块对Al^(3+)在复盐中的结合量和结合能进行分析,进而确立粗ZrCl_(4)除Al机制。Al^(3+)结合量的降低和结合能的升高有助于Al^(3+)从复盐中脱离,从而降低粗ZrCl_(4)中Al含量。通过实验与理论计算验证了锌离子路易斯酸熔盐体系能够从粗ZrCl_(4)中有效除Al。本研究可为制备高品质核级锆提供新思路和理论基础。

In order to reduce the content of Al impurity in the crude ZrCl_(4) prepared by traditional boiling chlorination process and meet the accuracy requirement of high-quality zirconium precursor,the zinc-ion Lewis acid molten salt system suitable for high efficiency removal of Al from crude ZrCl_(4) was developed.As a result,the content of Al impurity is reduced from 0.16%to 0.001%.According to the reaction of Lewis acid molten salt system with Al^(3+)in crude ZrCl_(4),the binding amount and binding energy of Al^(3+)in composite salts were analyzed by CASTEP module based on density functional theory,and then the Al re-moval mechanism from crude ZrCl_(4) was established.The decrease of the binding amount of Al^(3+)and the increase of the binding energy contribute to the separation of Al^(3+)from the composite salts,thus reducing the Al content in the crude ZrCl_(4).It is proved that the zinc-ion Lewis acid molten salt system can effective-ly remove Al from the crude ZrCl_(4) by experiments and theoretical calculation.This study can provide a new idea and theoretical basis for the preparation of high-quality nuclear-grade zirconium.