Abstract Air-assisted solvent extraction (AASX) in continuous-mode is a new development in the solvent extraction process for the extraction of valuable metals from dilute solutions. The main aim of this research was to investigate the effect of the flowrate of liquid and air phases on Cu recovery and organic phase recycling in a two-stage AASX system at pilot scale. The experiments were carried out in continuous-mode and the effect of the flowrates of liquid (18–30 L/min) and air (5–15 L/min for the first stage and 20–40 L/min for the second stage) were evaluated. Response surface methodology was used for designing the experiments, and results were analyzed by the analysis of variance (ANOVA). It was found that increasing the liquid flowrate reduced the Cu recovery in both stages by decreasing the retention time. While, enhancing the air flowrate in the first column increased the Cu recovery and organic phase recycling probably due to the adsorption of uncoated portion of the organic phase and collection of the smaller coated bubbles. Maximum Cu recovery (85%) and organic phase recycling (84%) were achieved at liquid flowrate of 18 L/min, first column aeration of 15 L/min, and second column aeration of 30 L/min for a solution containing 150 mg/L copper. Moreover, 98 and 94% Cu recoveries were obtained for 50 and 100 mg/L Cu solutions, respectively. The results indicated that using the newly developed AASX process, the application of the solvent extraction process could be extended to treat dilute metal-bearing solutions such as acid mine drainage.

中文翻译：

---

液体和空气流速对中试规模的两级空气辅助溶剂萃取系统效率的影响

摘要 连续模式空气辅助溶剂萃取 (AASX) 是溶剂萃取工艺的一项新进展，用于从稀溶液中萃取有价值的金属。本研究的主要目的是在中试规模的两级 AASX 系统中研究液相和空气相的流速对铜回收和有机相回收的影响。实验在连续模式下进行，液体（18–30 L/min）和空气（第一阶段为 5–15 L/min，第二阶段为 20–40 L/min）的流速的影响被评估。响应面方法用于设计实验，并通过方差分析（ANOVA）分析结果。发现增加液体流速通过减少保留时间降低了两个阶段的铜回收率。尽管，提高第一塔中的空气流速增加了铜回收率和有机相回收率，这可能是由于有机相未涂覆部分的吸附和较小的涂覆气泡的收集。对于含有 150 mg 的溶液，在 18 L/min 的液体流速、15 L/min 的第一次柱曝气和 30 L/min 的第二次柱曝气下实现了最大的 Cu 回收率 (85%) 和有机相回收率 (84%) /L 铜。此外，对于 50 和 100 毫克/升的铜溶液，分别获得了 98% 和 94% 的铜回收率。结果表明，使用新开发的 AASX 工艺，溶剂萃取工艺的应用可以扩展到处理含金属的稀溶液，如酸性矿山排水。