Abstract In this study, the ammonium thiosulfate leaching of gold (Au) from printed circuit boards (PCBs) of end-of-life mobile phones and the subsequent recovery of dissolved metals from pregnant leach solution via cementation were elucidated under various conditions. Over 99% of Au was extracted from crushed PCBs (D50 = 85 μm) under the following conditions: 1 M of Na2S2O3, 10 mM of CuSO4, 1 M of ammonia/ammonium concentration, 0.1 g/10 ml of solid-to-liquid ratio, and a 24-h of leaching time in the presence of oxygen. In contrast, the recovery of Au ions via cementation was more favorable in the absence of oxygen. Among the various cementation agents evaluated, copper (Cu) was the most selective and recovered around 95% of extracted Au from the pregnant leach solution even in the presence of various coexisting metal ions. The cementation of Au exhibited two distinct kinetic regions: (1) an initially rapid rate, and (2) a more gradual and constant rate. Finally, the use of Cu plates to recover Au ions from ammonium thiosulfate pregnant solution of crushed PCBs is proposed, which could selectively recover about 80% of dissolved Au and is easier to handle and reuse compared with Cu powder.

中文翻译：

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硫代硫酸铵从报废手机印刷电路板 (PCB) 中提取金并通过胶结从富浸液中回收

摘要 在这项研究中，阐明了在各种条件下从报废手机的印刷电路板 (PCB) 中浸出金 (Au) 的硫代硫酸铵以及随后通过胶结从富集浸出液中回收溶解金属。在以下条件下从粉碎的 PCBs (D50 = 85 μm) 中提取了超过 99% 的 Au：1 M Na2S2O3、10 mM CuSO4、1 M 氨/铵浓度、0.1 g/10 ml 固体到液体在氧气存在下，浸出时间为 24 小时。相比之下，在没有氧气的情况下，通过胶结回收金离子更有利。在评估的各种粘结剂中，铜 (Cu) 的选择性最强，即使在各种共存金属离子存在的情况下，也能从富集浸出液中回收约 95% 的提取金。Au 的胶结表现出两个不同的动力学区域：(1) 最初的快速速率，和 (2) 更渐进和恒定的速率。最后，提出了使用铜板从粉碎的 PCBs 硫代硫酸铵母液中回收金离子，与铜粉相比，可以选择性地回收约 80% 的溶解金，并且更易于处理和再利用。