(廣東省稀有金屬研究所，廣東省稀土開發(fā)及應(yīng)用重點(diǎn)實(shí)驗(yàn)室，廣州 510650)
摘 要: 針對(duì)南方離子型稀土中鈾、釷的放射性水平開展了調(diào)查，并根據(jù)南方離子型稀土生產(chǎn)過程中放射性元素鈾、釷的分布、走向規(guī)律特點(diǎn)，首次提出采用環(huán)烷酸萃取劑預(yù)先萃取分離浸礦原液中的鈾、釷。考察料液酸度、萃取相比、萃取時(shí)間、萃取劑皂化度及萃取級(jí)數(shù)對(duì)萃取的影響規(guī)律，并對(duì)反萃實(shí)驗(yàn)進(jìn)行研究。實(shí)驗(yàn)表明：REO=1.75 mol/L的稀土料液，采用15%環(huán)烷酸+15%異辛醇+70%磺化煤油(體積分?jǐn)?shù))萃取劑體系，在最佳萃取條件下：料液酸度pH為1.0~3.5，萃取時(shí)間10 min，萃取相比O/A=2:1，采用邊萃取邊皂化方式，按6 mL/min速度加入0.6 mol/L NaOH溶液(VNaOH:Vextractant=1:100)單級(jí)鈾萃取率達(dá)98.6%，釷萃取率達(dá)33.3%，負(fù)載有機(jī)相采用5 mol/L鹽酸按相比(O/A)20:1三級(jí)逆流反萃，鈾、釷反萃取率均達(dá)100%。
關(guān)鍵字: 南方離子型稀土；放射性；環(huán)烷酸；萃取；鈾；釷
（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
