苯并15-冠-5—离子液体体系多级逆流萃取分离锂同位素研究

锂的两种天然同位素（6Li和7Li）在能源、环境和国防安全等领域具有重要应用价值。本文以氯化锂溶液为原料，选用苯并15-冠-5和咪唑类离子液体体系对其进行了模拟逆流萃取实验，考察了多级逆流萃取过程中锂的萃取率和锂同位素分离系数的变化规律，结果表明：经10级逆流萃取后，锂的萃取率和同位素分离系数有了明显提高，6Li富集在有机相，丰度提高了0.2996%，本文对锂同位素富集浓度和富集行为进了研究探讨。

Multi-stage Countercurrent Extraction Separation of Lithium Isotopes by using Benzo-15-crown-5/Ionic Liquid System

The two natural isotopes of lithium, 6Li and7Li, have important application value in related fields, such as energy, environment, national defense security and so on. In this paper, a simulated reverse counter-current extraction experiment was carried out, in which lithium chloride solution was used as raw material, and benzo-15-crown-5 and ionic liquids were used for extracting lithium ions from the solution. The experiment investigated the change rules of extraction efficiency for lithium ions and separation coefficient of lithium isotopes during the process of multi-stage countercurrent extraction. when 10-stage countercurrent extraction experiment was finished, the results showed that the extraction efficiency for lithium ions and separation coefficient of lithium isotopes were obviously improved; 6Li was enriched in the organic phase and its enrichment rate increased by 0.2996%. Moreover, we gave a discussion about enrichment concentration and behavior of lithium isotope.