Solvent extraction based on ionic liquids is generally considered to be an environmentally benign and effective technology for gold(I) recovery. The aim of this work is to study gold(I) extraction from aurocyanide solution using fluorine-free ionic liquids [A336][SCN], [A336][MTBA] and [A336][Mal]. Various factors that affect gold(I) extraction (including concentration of ionic liquids, equilibrium pH, concentration of the modifier tributyl phosphate (TBP), reaction time and initial concentration of gold in an aqueous solution) were studied and optimized. The results indicate that the three Aliquat 336-based ionic liquids all exhibit excellent behaviors for gold(I) extraction. More than 99.8% of gold(I) can be extracted from the aqueous phase into the ionic liquid phase. The gold-loaded ionic liquids were characterized using infrared spectroscopy and mass spectrometry to study the extraction mechanism of gold(I). The results revealed that extraction of gold(I) into the ionic liquid phase was based on an exchange reaction between the anion Au(CN)2− in aqueous solution and the anion SCN− in ionic liquid [A336][SCN]. The logarithmic relationship between distribution coefficient and TBP concentration indicates that two TBP molecules are involved in the formation of the extracted complex. The extracted complex was determined to be A336+·Au(CN)2−·2TBP. In addition, the gold(I)-loaded ionic liquids can be efficiently stripped using NH4SCN, 2-methylthiobenzoic acid and methyl maltol. The results establish that Aliquat 336-based ionic liquids have potential application prospects in gold(I) recovery from cyanide solutions.

中文翻译：

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无氟离子液体从碱性金氰化物溶液中提取金(I)的平衡与机理研究

基于离子液体的溶剂萃取通常被认为是一种环境友好且有效的金（I）回收技术。这项工作的目的是研究使用无氟离子液体 [A336][SCN]、[A336][MTBA] 和 [A336][Mal] 从金氰化物溶液中提取金 (I)。研究并优化了影响金 (I) 萃取的各种因素（包括离子液体浓度、平衡 pH 值、改性剂磷酸三丁酯 (TBP) 的浓度、反应时间和金在水溶液中的初始浓度）。结果表明，三种基于 Aliquat 336 的离子液体都表现出优异的金 (I) 提取行为。超过 99.8% 的金 (I) 可以从水相中提取到离子液相中。使用红外光谱和质谱对载金离子液体进行表征，以研究金（I）的提取机理。结果表明，将金（I）提取到离子液相中是基于水溶液中的阴离子 Au(CN)2- 与离子液体中的阴离子 SCN- [A336][SCN] 之间的交换反应。分配系数与 TBP 浓度之间的对数关系表明两个 TBP 分子参与了提取复合物的形成。提取的复合物经测定为A336+·Au(CN)2-·2TBP。此外，负载金 (I) 的离子液体可以使用 NH4SCN、2-甲硫基苯甲酸和甲基麦芽酚有效地剥离。结果表明，基于 Aliquat 336 的离子液体在从氰化物溶液中回收金 (I) 方面具有潜在的应用前景。