Purification of concentrated manganese sulfate solution by solvent extraction is discussed in this paper. The use of bis(2-ethylhexyl) hydrogen phosphate (D2EHPA) and bis(2,4,4-trimethylpentyl)phosphinic acid (BTMPPA) was studied in removal of impurities from zinc electrowinning anode sludge leachates. Over 99 % of zinc and iron were removed by both extractants at around pH 3 in two mixer-settlers operating in continuous countercurrent mode at a solvent-to-feed (S/F) ratio of 0.43 and T = 22 ± 1 °C. BTMPPA had higher selectivity for zinc and iron over manganese than D2EHPA under all experimental conditions. Extraction of manganese was typically below 10 % and can be limited by crowding the extractants, since the fraction of manganese in both loaded extractants was decreased by decreasing organic to aqueous volumetric ratio (O/A). A significant amount of the co-extracted Mn was recovered by selective stripping with 0.5 M sulfuric acid. Extraction by BTMPPA was more sensitive to pH adjustment than extraction by D2EHPA. Increasing the mean residence time in mixer from 3.6 min to 6.0 min improved the removal of zinc and iron with BTMPPA but the change in residence time had little or no effect on zinc and iron removal with D2EHPA.

本文讨论了溶剂萃取法提纯浓硫酸锰溶液。研究了使用双（2-乙基己基） 磷酸氢盐 （D2EHPA）和双（2,4,4-三甲基戊基）次膦酸（BTMPPA）去除锌电积阳极污泥浸出液中的杂质。在两个以连续逆流模式运行、溶剂与进料 (S/F) 比为 0.43 和T  = 22 ± 1 °C 的混合沉降器中 ，两种萃取剂在 pH 值约为 3 时去除了超过 99 % 的锌和铁。在所有实验条件下，与 D2EHPA 相比，BTMPPA 对锌和铁的选择性高于锰。锰的提取通常低于 10 % 并且可以通过拥挤萃取剂来限制，因为两种负载萃取剂中锰的分数通过降低有机物与水的体积比 (O/A) 来降低。通过用 0.5 M 硫酸选择性汽提，回收了大量共萃取的 Mn。BTMPPA 提取比 D2EHPA 提取对 pH 调节更敏感。将混合器中的平均停留时间从 3.6 分钟增加到 6.0 分钟，可以提高 BTMPPA 对锌和铁的去除效果，但停留时间的变化对 D2EHPA 对锌和铁的去除影响很小或没有影响。