湿法分离锆铪的研究进展

Research Progress in Hydrometallurgical Separation of Zirconium and Hafnium

锆铪分离是制备核级锆和铪的技术关键。简单综述了工业上生产核级锆铪的主要溶剂萃取分离工艺,即甲基异丁基酮(MIBK)法、磷酸三丁酯(TBP)法、三辛胺或三烷基叔胺(TOA或N235)法,并对各种工艺流程的优劣进行了技术分析,重点介绍了中性萃取体系、酸性萃取体系、螯合萃取体系、碱性萃取体系和协同萃取体系等溶剂萃取分离锆铪技术的新进展。另外,还阐述了其他锆铪湿法分离的方法如分步结晶和沉淀法、吸附分离法、膜分离法、微溶剂萃取法、双水相萃取法和液膜萃取法对锆铪进行富集和分离的现状。可以发现,新开发的锆铪湿法分离技术大都是优先分离锆铪原料中含量较多的锆,且大多仅进行了分离工艺的研究,而对锆铪分离的机制、热力学和动力学的相关研究较少。为了提高分离效率和保护环境,开发优先萃取铪且环境友好型的绿色分离体系显得尤为必要。

The separation between zirconium and hafnium is the key technology to prepare nuclear-grade zirconium and hafnium. Several solvent extraction separation processes to produce nuclear-grade zirconium and hafnium in industry, such as methyl isobutyl ketone （MIBK）, tributyl phosphate （TBP） and trio etylamine or trialkyl tertiary amine （TOA or N235 ） methods, were briefly reviewed, and their advantages and disadvantages were discussed in the view of technology. Besides, several latest research progress in zirconium and hafnium separation by solvent extraction methods, such as neutral extraction system, acidic extraction system, chelating extraction system, alkaline extraction system, and synergistic extraction system, were emphatically introduced, respectively. In addition, some of other hydrometallurgical separation techniques, including fractional crystallization and precipitation method, adsorption separation method, membrane separation method, micro solvent extraction method, aqueous biphasic system method and liquid membrane method were also presented. It could be found that newly developed hydrometallurgical separation methods were mainly focused on the separation of zirconium prior to hafnium. Moreover, most of works were mainly concerned with separation process rather than mechanism, thermodynamic and kinetic. In order to improve the separation efficiency and protect environment as well, the development of a new extraction system separating hafnium as well as friendly to environment was particularly on the trend.