Abstract Ionic liquid (IL) based on tetraheptylammonium cooking oil (TC) was used for the first time to recovery rare earth elements (REEs) from leaching liquor of ion-adsorbed-type rare earths ores. Firstly, extraction performances of tetraheptylammonium oleate (TO) and tetraheptylammonium linoleate (TL) type ILs were investigated. It was shown that these ILs had good extraction performances, such as short equilibrium time less than 1 min, good extraction capacity of 0.225 mol/L and high stripping efficiency of 99%. Additionally, REEs extraction occurred in the solutions with high acidity (pH = 0.24) because the cation (C7H15)4N+ of TO and TL could form a strong amine salt with hydrogen ion to decrease acidity of the feed solution. Also, an ion association mechanism of REEs extraction was proposed by FT-IR spectra, 1H NMR investigation and slope analysis method. Secondly, TC was synthesized in water bath by mixing tetraheptylammonium bromide with saponified peanut oil. Then, comparative study of commercial extractants showed that TC had the highest REEs recovery yield of 100% from the leaching liquor. The sustainability, biocompatibility and non-toxicity, as well as simple synthesis route and well extraction performances make these cooking oil based ILs promising for REEs recovery from the leaching liquor.

中文翻译：

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基于食用油的离子液体从离子吸附型稀土矿浸出液中回收稀土元素

摘要 以四庚铵食用油（TC）为基础的离子液体（IL）首次用于从离子吸附型稀土矿浸出液中回收稀土元素（REEs）。首先，研究了四庚基油酸铵（TO）和四庚基亚油酸铵（TL）型离子液体的提取性能。结果表明，这些离子液体具有良好的萃取性能，如小于1 min的平衡时间短、0.225 mol/L的良好萃取能力和99%的高汽提效率。此外，由于 TO 和 TL 的阳离子 (C7H15)4N+ 可与氢离子形成强胺盐，从而降低进料溶液的酸度，因此在高酸度 (pH = 0.24) 的溶液中会发生 REE 萃取。此外，通过 FT-IR 光谱提出了 REE 提取的离子缔合机制，1H NMR调查和斜率分析方法。其次，将四庚基溴化铵与皂化花生油混合，在水浴中合成TC。然后，对商业萃取剂的比较研究表明，TC 从浸出液中具有最高的 100% REE 回收率。可持续性、生物相容性和无毒，以及简单的合成路线和良好的提取性能，使这些食用油基离子液体有望从浸出液中回收 REE。