Extraction Mechanism of Lithium from the Alkali Solution with Diketonate-Based Ionic Liquid Extractants
Extraction Mechanism of Lithium from the Alkali Solution with Diketonate-Based Ionic Liquid Extractants
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DOI：
10.1021/acs.energyfuels.0c02346
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发表时间：
2020-08
期刊：
影响因子：
5.3
通讯作者：
Junfeng Wang;Shicheng Yang;Xiaofei Zhang;Yilin Wang;Daoguang Wang;Weichao Li;M. Ashraf;A. Park;Xingchun Li
中科院分区：
文献类型：
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作者：
Junfeng Wang;Shicheng Yang;Xiaofei Zhang;Yilin Wang;Daoguang Wang;Weichao Li;M. Ashraf;A. Park;Xingchun Li
合成了4种含三烷基甲基铵（[A336]+）的双酮基功能离子液体（IL），并将其与三烷基氧膦（TRPO）协同萃取体系用于从LiCl和Na 2CO 3反应生成Li 2CO 3的溶液中分离Li+。与其前体1，3-二酮相比，在1.26-10.17的较宽pH范围内，离子液体从高Na/Li质量比的溶液中表现出更高的Li+萃取能力。在四种离子液体中，含噻吩甲酰三氟丙酮（TTA-）阴离子的离子液体对Li+的分离能力最好。在优化条件下，[A336]的产率达到83.26%，远高于其前驱体的产率（71.50%）。斜率分析和表征结果表明，在含和不含TRPO的体系中，萃取Li+的形态分别为Li 2CO 3·2 <$[A336]<$TTA·TRPO和Li 2CO 3·4 <$[A336]<$TTA。最后，对三级萃取工艺进行了验证，并从青海中信国安科技发展有限公司提供的溶液中回收Li+的效率，Ltd.（CITIC）的萃取率达到97.16%，表明[A336] Na 2 TTA + TRPO萃取体系能有效地从碱性水溶液中分离锂。
Four diketonate-based functional ionic liquids (ILs) with trialkylmethylammonium ([A336]+) cation were synthesized, and the synergistic extraction systems containing IL and thetrialkylphosphineoxide (TRPO) were developed to separate Li+ from the solution generated during the Li2CO3 production by the reaction of LiCl and Na2CO3. Compared to their precursors 1,3-diketones, over the wide pH range of 1.26–10.17, ILs showed higher Li+ extractability from the solution with a high Na/Li mass ratio. Among the four ILs, the IL with 2-thenoyl-trifluoroacetonate (TTA–) anion showed the best Li+ separation ability. Under the optimized conditions, [A336]TTA was up to 83.26%, which was much higher than that of its precursor (71.50%). The results of slope analysis and characterizations indicated that the extracted Li+ species using the extraction systems with or without TRPO were Li2CO3·2[A336]TTA·TRPO and Li2CO3·4[A336]TTA, respectively. Finally, a three-stage extraction process was validated, and the recovery efficiency of Li+ from the solution provided by Qinghai CITIC Guoan Science and Technology Development Co., Ltd. (CITIC) was up to 97.16%, indicating that the extraction system of [A336]TTA + TRPO was efficient for separating lithium from the alkaline aqueous solution.