Abstract The supply of fresh water is becoming an increasingly important issue in hydrometallurgical treatment of mineral ores. The problem may significantly reduce if the extraction process can incorporate the usage of saltwater throughout the whole hydrometallurgical operation. Seawater as the main source of saltwater is a potential alternative to freshwater. In this research, the effect of the chloride ions, in a range of 0 to 40 g/L, on the solvent extraction of copper with LIX 984N was studied. LIX 984N has been commercially used in copper solvent extraction around the world. Increasing the concentration of Cl− was shown to increase the H+ activity and formation of CuCl+ and CuCl2 species. The solution acidity did not have a negative effect on the extent of copper extraction and extraction rate, in the presence and absence of chloride ion, in contrast to recent studies. The chloride addition was even showed to have a positive impact on copper extraction at pHs below 2 and at shorter mixing times. Through thermodynamic studies, it was shown that increasing chloride concentration results in both higher H+ activity and an increase in the activity of copper chloride complexes, of which the latter factor counteracts the former and overall improves the extent of copper extraction. Increasing the chloride concentration was found to negatively affect the copper extraction isotherms. The impact became more significant at lower concentrations of the extractant. It is therefore suggested that cupric chloride complex ion inhibits copper extraction by lowering the extraction driving forces. Also, it was shown that increasing aqueous chloride concentration promotes involvement of more extractant molecules per Cu2+ species in the extraction reaction in contrast to the reaction without chloride ions. The negative effect of chloride ions on copper solvent extraction then is due to the change in the reaction stoichiometry and decrease in the extraction driving force rather than the types of aqueous Cu2+ speciation. The effect of wash stages on the removal of the chloride ion from loaded organic solution was then investigated and the optimum conditions for the wash stage were found at wash solution to loaded organic ratio of 1 to 7 and sulfuric acid concentration of 10 g/L.

中文翻译：

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氯离子对使用 LIX 984N 从硫酸盐-氯化物介质中萃取铜的影响

摘要 淡水的供应正成为矿物湿法冶金处理中越来越重要的问题。如果提取过程可以在整个湿法冶金操作中使用盐水，则问题可能会显着减少。海水作为咸水的主要来源，是淡水的潜在替代品。在本研究中，研究了 0 至 40 g/L 范围内的氯离子对使用 LIX 984N 溶剂萃取铜的影响。LIX 984N 已在全球范围内商业用于铜溶剂萃取。增加 Cl− 的浓度显示出增加 H+ 活性和 CuCl+ 和 CuCl2 物种的形成。溶液酸度对铜的提取程度和提取率没有负面影响，在氯离子存在和不存在的情况下，与最近的研究相反。在 pH 值低于 2 和混合时间较短的情况下，氯化物的添加甚至显示出对铜萃取的积极影响。通过热力学研究表明，增加氯化物浓度会导致更高的 H+ 活性和氯化铜配合物的活性增加，其中后一个因素抵消了前者，总体上提高了铜的提取程度。发现增加氯化物浓度会对铜萃取等温线产生负面影响。在较低浓度的萃取剂下，影响变得更加显着。因此建议氯化铜络离子通过降低提取驱动力来抑制铜提取。还，结果表明，与没有氯离子的反应相比，增加氯化物水溶液的浓度会促进每个 Cu2+ 物质在萃取反应中参与更多的萃取剂分子。氯离子对铜溶剂萃取的负面影响是由于反应化学计量的变化和萃取驱动力的降低，而不是由于含水 Cu2+ 形态的类型。然后研究洗涤阶段对从负载的有机溶液中去除氯离子的影响，并发现洗涤阶段的最佳条件为洗涤溶液与负载的有机物比为 1:7，硫酸浓度为 10 g/L。氯离子对铜溶剂萃取的负面影响是由于反应化学计量的变化和萃取驱动力的降低，而不是由于含水 Cu2+ 形态的类型。然后研究洗涤阶段对从负载的有机溶液中去除氯离子的影响，并发现洗涤阶段的最佳条件为洗涤溶液与负载的有机物比为 1:7，硫酸浓度为 10 g/L。氯离子对铜溶剂萃取的负面影响是由于反应化学计量的变化和萃取驱动力的降低，而不是由于含水 Cu2+ 形态的类型。然后研究洗涤阶段对从负载的有机溶液中去除氯离子的影响，并发现洗涤阶段的最佳条件为洗涤溶液与负载的有机物比为 1:7，硫酸浓度为 10 g/L。