Abstract:

To solve the problems of phase separation difficulty, extractant loss and large equipment existing in the liquid-liquid extraction system, a solvent extraction method with coaxial microchannel device was applied to prepare polysulfone microcapsules and the extraction performance of Sm³⁺ by microcapsules containing P507 was investigated and optimized. Extraction kinetics, stripping property and stability of microcapsules containing P507 was studied systematically. The advantages of microcapsule system were highlighted, i.e., simple operation, little extractants loss and high stability. To enhance the mass transfer, and improve extraction and stripping rate, P507 was diluted with kerosene and the extraction performance in the liquid-liquid system was studied. The best extraction performance was obtained when the volume fraction of P507 in solution was 40%. Compared with microcapsules containing pure P507, the extraction performance of microcapsules containing 40%(vol) P507/60%(vol) kerosene was significantly promoted-the extraction equilibrium time was shortened from 120 min to 40 min, the equilibrium capacity was improved from 45.09 mg·(g P507)^-1 to 69 mg·(g P507)^-1, the utilization of P507 was increased from 55% to 84%, and the equilibrium stripping time was decreased from 600 min to 120 min. In conclusion, the diluting P507 with kerosene can effectively improve the extraction kinetics, equilibrium extraction capacity and stripping rate. 20 cycles of extraction and stripping demonstrated a good stability of microcapsules after diluting P507 with kerosene.

Key words: Sm³⁺, P507, microcapsule, immobilization, recovery, extraction

摘要：

为解决传统溶剂萃取回收稀土中两相分离困难、溶剂流失和设备庞大的问题,利用溶剂萃取法结合同轴环管微通道装置制备聚砜微胶囊,研究了微胶囊固定化P507 对Sm³⁺的萃取性能及其优化。系统地考察了微胶囊固定化P507 对Sm³⁺ (300 mg·L^-1) 的萃取动力学、反萃性能和循环萃取反萃稳定性,揭示了微胶囊萃取体系的优点,操作简单、萃取剂流失较小、稳定性高。为强化传质过程,提高萃取、反萃动力学,用煤油稀释负载的P507,考察P507-煤油溶液中P507 体积分数对萃取效果的影响。P507-煤油溶液中的P507 体积分数为40%时,在液液体系中对Sm³⁺的萃取效果最好。将其用于微胶囊体系中,和稀释前相比,萃取平衡时间由120 min 缩短到40 min,萃取容量从由45.09 mg·(g P507)^-1 增大到69 mg·(g P507)^-1,P507 利用率由55%提高到84%,反萃完成时间由600 min 减小到120 min。用煤油稀释负载的P507 能有效提高萃取速率、平衡萃取量和反萃速率。20 次萃取反萃循环表明P507 稀释后微胶囊仍然具有较好的稳定性。

关键词: Sm³⁺, P507, 微胶囊, 固定化, 回收, 萃取