双官能团（P=O,N）萃取剂的设计合成、萃淋树脂的制备及其分离稀土的研究

High purity of rare earths has an irreplaceable role in high-tech fields, but rare earths preparing with single functional group extractants can’t meet the special requirements of high performance materials. To solve this problem, this project design and synthesis bi-functional group extractants, which combine the advantage of phosphonic extractants and amine extractants. Phosphonic extractants exhibit excellent separation performance toward rare earths and amine extractant show low extraction acid and easy stripping acid. Systematic thermodynamic and kinetic research on separation rare earths using bi-functioned extractants will be carried out and the separation factors between adjacent rare earths will be calculated; functional resins will be prepared by fixing the novel extractant by chemical bond, the separation factors of adjacent rare earths will be studied. During solvent extraction and adsorption process, analysis method will be used to clarify the synergistic effects between two functional groups and binding modes with metal ions and explaining the mechanism in extraction and adsorption process. Selection of the factors that can improve the separation efficiency of rare earths, such as extractant structures, the experimental conditions and so on. This project will not only provide a new way to design high efficiency extractant, but also provide a scientific basis for preparation of high purity rare earths.

高纯稀土在新材料制备中具有不可替代作用，开发高纯稀土对材料领域的发展有着重大意义，但目前常用的单一官能团萃取剂制备的稀土纯度尚不能完全满足高性能材料的要求。针对这一问题，本项目拟将磷/膦类萃取剂对稀土离子具有优异萃取分离能力的优势和胺类萃取剂萃取酸度低、反萃容易的特性结合起来，设计合成同时含有膦酰基以及胺基两种官能团的萃取剂；系统研究该类化合物萃取稀土的热力学和动力学机理，比较其对稀土的分离性能；进一步将该萃取剂通过化学反应键合到树脂上，研究功能化萃淋树脂对相邻稀土元素的分离系数；利用现代分析方法阐明萃取、吸附过程中官能团之间的内协同效应以及它们与金属离子的结合结构，进一步阐释萃取、吸附机理，进而指导萃取剂的合成并优化对稀土离子的萃取工艺。该研究不仅为高纯稀土元素的制备打下基础，同时也为新型高效萃取剂的设计合成提供了新的思路。

本项目针对我国传统工业萃取剂分离系数小、反萃酸度高等问题，提出将磷/膦类萃取剂对稀土离子具有优异萃取分离能力的优势和胺类萃取剂萃取酸度低、反萃容易的特性结合起来，合成同时含有两种官能团的萃取剂及萃淋树脂。按照项目计划书，采用曼尼希方法合成了多种双官能团萃取剂，采取多种化学表征手段对基于新型双官能团萃取剂的稀土分离体系展开了深入研究，阐明了稀土萃取机理。筛选出分离系数高于P507，饱和容量高于Cyanex272，反萃酸度低于P507，综合萃取性能优良的新型萃取剂EEAMPA。研究表明其对相邻重稀土元素的分离系数βTm/Er, βYb/Tm, βLu/Yb 分别为1.97, 2.37, 1.63, 可对重稀土离子进行高效分离。为提高树脂的稳定性，利用化学反应将筛选出的官能团键合到树脂上，制备了双官能团萃淋树脂。研究了双官能团树脂对金属离子的吸附动力学、饱和吸附容量、反萃酸度以及树脂的循环稳定性。采用红外光谱、扫描电镜等化学方法对树脂吸附前后进行表征，阐明了吸附机理。上述研究有助于为制备单一高纯稀土离子的分离工艺提供数据支撑和科学依据。