(广东省稀有金属研究所，广东省稀土开发及应用重点实验室，广州 510650)
摘 要: 针对南方离子型稀土中铀、钍的放射性水平开展了调查，并根据南方离子型稀土生产过程中放射性元素铀、钍的分布、走向规律特点，首次提出采用环烷酸萃取剂预先萃取分离浸矿原液中的铀、钍。考察料液酸度、萃取相比、萃取时间、萃取剂皂化度及萃取级数对萃取的影响规律，并对反萃实验进行研究。实验表明：REO=1.75 mol/L的稀土料液，采用15%环烷酸+15%异辛醇+70%磺化煤油(体积分数)萃取剂体系，在最佳萃取条件下：料液酸度pH为1.0~3.5，萃取时间10 min，萃取相比O/A=2:1，采用边萃取边皂化方式，按6 mL/min速度加入0.6 mol/L NaOH溶液(VNaOH:Vextractant=1:100)单级铀萃取率达98.6%，钍萃取率达33.3%，负载有机相采用5 mol/L盐酸按相比(O/A)20:1三级逆流反萃，铀、钍反萃取率均达100%。
关键字: 南方离子型稀土；放射性；环烷酸；萃取；铀；钍
（Guangdong Province Research Institute of Rare Metals, Guangdong Province Key Laboratory of Rare Earth Development and Application, Guangzhou 510650, China）
Abstract:The radioactivity level of U and Th in ion-adsorption rare earth was surveyed. And basing on the distribution and movement law characteristics of radioactive elements U and Th in the production process of ion-adsorption rare earth, extraction and separation of U and Th in rare earth leaching liquid beforehand by Naphthenic acid were put forward. The effects of feed acidity, extraction time, extraction phase ratio, extractant saponification degree on the extraction and stripping experiments were investigated. The results show that with 15% (volume fraction) naphthenic acid and 15% isooctyl alcohol in 70% sulphonated kerosene as extractant, the extraction ratios of U and Th from the solution (REO=1.75 mol/L) with pH 1.0-3.5 reach 98.6 % and 33.3%, respectively, in single-stage extraction process with O/A ratio of 2:1 for 10 min which is added 0.6 mol/ L NaOH solution(VNaOH:Vextractant=1:100) at speed of 6 mL/min at the same time.The U and Th in loaded organic can be stripped completely using 5 mol/L HCl solution in three-stage counter current stripping process with O/A ratio of 20:1.
Key words: ion-adsorption rare earth; radioactivity; naphthenic acid; extraction; U; Th
