Abstract A sandwiched liquid-membrane electrodialysis system, which combines the characteristics of liquid-membrane extraction and electrodialysis, has been proposed here to realize the selective extraction of lithium from salt-lake brines with high Mg/Li mass ratio. The sandwiched liquid membrane is comprised of 2 cation exchange membranes and a Li+-loaded organic liquid film. Because of the moderate working environment and satisfactory performance, the TBP + ClO4- system is chosen as the liquid film out of four candidates, namely TBP + FeCl3 system, TBP + ClO4- system, N-butanol, and β-diketone. According to the electrodialysis experiments then, the Mg/Li ratio in catholyte is reduced to lower than 2 from 100 in the initial brine and the specific energy consumption is as low as 0.13 kWh·mol−1 Li. Additionally, the optimal voltage and temperature for the electrodialysis process are determined as 3.00 V and 20 °C. Finally, we also conclude that this approach is highly adaptable to brines with different cation compositions, because of its ability to separate Li+ with other impurity cations in brine (Na+, K+, Mg2+, and Ca2+). With high adaptability and low energy consumption, this sandwiched liquid-membrane electrodialysis system provides a promising perspective for lithium extraction and separation from brines with high Mg/Li ratio.

中文翻译：

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夹心液膜电渗析：从高镁锂比盐湖卤水中选择性回收锂

摘要 本文提出了一种结合液膜萃取和电渗析特点的夹层式液膜电渗析系统，以实现从高镁锂质量比的盐湖卤水中选择性提取锂。夹心液膜由 2 个阳离子交换膜和一个负载 Li+ 的有机液膜组成。由于工作环境温和，性能令人满意，从TBP+FeCl3体系、TBP+ClO4-体系、正丁醇和β-二酮四种候选体系中选择TBP+ClO4-体系作为液膜。根据随后的电渗析实验，阴极电解液中的Mg/Li比从初始盐水中的100降至2以下，单位能耗低至0.13 kWh·mol-1 Li。此外，电渗析过程的最佳电压和温度确定为 3.00 V 和 20 °C。最后，我们还得出结论，该方法高度适用于具有不同阳离子组成的盐水，因为它能够将 Li+ 与盐水中的其他杂质阳离子（Na+、K+、Mg2+ 和 Ca2+）分离。这种夹层式液膜电渗析系统适应性强、能耗低，为从高镁锂比的卤水中提取和分离锂提供了广阔的前景。