刘 超 赵 龙＊, 韦悦周 何林峰 唐方东

(1上海交通大学核科学与工程学院，核能化工实验室，上海200240)

(2上海市计量测试技术研究院，化学与电离辐射计量技术研究所，上海201203)

TODGA/[C2mim][NTf2]萃取Th4+

刘 超1赵 龙＊,1韦悦周1何林峰2唐方东2

(1上海交通大学核科学与工程学院，核能化工实验室，上海200240)

(2上海市计量测试技术研究院，化学与电离辐射计量技术研究所，上海201203)

The extraction behavior of Th4+from nitric acid solution with N,N,N′,N′-tetraoctyldiglycolamide (TODGA)dissolved in hydrophobic ionic liquid[C2mim][NTf2]was studied.The effect of contact time,acidity,Th4+concentration，TODGA concentration and temperature on the extraction performance of TODGA/[C2mim][NTf2] system were investigated.For comparison,the same experiment in TODGA/isooctane system was also done.The results showed that the extraction of TODGA/[C2mim][NTf2]system against Th4+was endothermic reaction and could balance within 5 min at 50℃.The extraction efficiency decreased first and then increased with the increasing of acidity and Th4+concentration as well as decreasing of TODGA concentration.It was found that TODGA/[C2mim][NTf2]system had better extraction efficiency than TODGA/isooctane system especially at low acidity.The extraction mechanism was suggested that at low acidity the extraction proceed via ion exchange mechanism to a coordination compound，and the mechanism at the high acidity was neutral complex.

Th4+;N,N,N′,N′-tetraoctyldiglycolamide;ionic liquid;extraction

钍(232Th)是一种存在于自然界中天然放射性元素，其在自然界的储量非常丰富，约为铀(U)储量的3倍多。232Th本身不易裂变，但可以通过吸收中子经过一系列的核反应(232Th→233Th→233Pa→233U)生成人工易裂变核素233U，具有很好的核性能。因此，232Th可能在未来有效地克服铀资源的不足，使其在核能方面有很广阔的应用前景。

目前，钍的分离方法主要有色谱萃取法、液液萃取法[1-4]等。色谱萃取法具有占地少，易操作等优点，但是也存在萃取时间长、吸附容量低、色谱柱制备困难等缺点；而液液萃取法由于具有快速，选择性好和高容量等优点，是目前分离工艺中最常使用的方法。但是，液液萃取体系中，使用的稀释剂多为有机溶剂，使用中会存在一定的安全性问题，特别是会出现易劣化，溶解性和溶剂挥发等问题。因此稀释剂的选择对液液萃取体系来说很重要。

室温离子液体由体积相对较大的结构不对称的有机阳离子和相对较小的无机阴离子构成，在室温或近于室温下呈液态。相对于传统有机溶剂而言，它具有多方面的优点，如：低挥发性、低熔点、液态温度范围宽；……