Abstract Since indiumisconsidereda strategic material, a study for developing and optimizing a recovery process by electrowinning has been performed. The possibility of using electrolytic baths based on sulfates instead of chlorides has also been evaluated. Nowadays, chlorides are widely used because they generally present greater current efficiencies;however, the dangers of chlorine gasrequireexpensive-sealed systems to avoid human health and environmental issues. The use of sulfatesdoes not present the same problems;therefore the electrowinning process optimization can represent a definite indium recovery improvement. For this purpose, the effects of electrolyte composition, temperature, current density and pH on the quality of the deposit, specific energy consumption (SEC) and current efficiency (CE) have been assessed. The sulfate electrolytic solutionhas been then appropriately modified with organic additives, mineral salts and complexing agents to optimize the indium recovery by electrowinning. ACE of about80% and SEC equal to 2.7 kWh/kg have been obtained, operating with a pH in the range 2.2–2.3 at 40 °C and using 25 A/m2 current density with an electrolytic solution containing 60 g/l of In3+, 30 g/l of Na2SO4, 20 g/l of Al2(SO4)3 and 20 g/l of H3BO3.

中文翻译：

---

影响硫酸盐浴中铟电解沉积效率的工艺参数

摘要 由于铟被认为是一种战略材料，因此已经进行了开发和优化电解提取回收工艺的研究。还评估了使用基于硫酸盐而不是氯化物的电解槽的可能性。如今，氯化物被广泛使用，因为它们通常具有更高的电流效率；然而，氯气的危险需要昂贵的密封系统来避免人类健康和环境问题。硫酸盐的使用不会出现同样的问题；因此电解沉积工艺优化可以代表一定的铟回收率改进。为此，已经评估了电解质成分、温度、电流密度和 pH 值对沉积物质量、比能量消耗 (SEC) 和电流效率 (CE) 的影响。然后用有机添加剂、矿物盐和络合剂对硫酸盐电解液进行适当改性，以优化电解沉积的铟回收率。已获得约 80% 的 ACE 和等于 2.7 kWh/kg 的 SEC，在 40 °C 下在 2.2-2.3 的 pH 值范围内运行，并使用 25 A/m2 电流密度和含有 60 g/l In3+ 的电解液， 30 g/l Na2SO4、20 g/l Al2(SO4)3 和 20 g/l H3BO3。