Abstract An efficient process for the recovery of palladium from waste printed circuits boards (PCBs) is detailed. Palladium is employed as an electrode material in multi-layer ceramic capacitors (MLCCs). These components can be easily removed from PCBs by de-soldering. As palladium is alloyed with silver, its dissolution is readily achieved using dilute nitric acid. As a result, a solution containing palladium along with base metals, mostly copper and iron, is obtained. This solution is then processed through solvent extraction (SX) with a solvent based on N,N′-dimethyl,N,N′-dibutyltetradecylmalonamide (BDMA), a robust extracting molecule previously developed in the frame of the reprocessing of waste nuclear fuel. The volume of effluents generated during the SX sequence is limited: iron scrubbing is operated with a very low aqueous to organic phase volume ratio, no specific metal chelator is required for palladium stripping, and no shift from acidic to basic media is required. Finally, a ca 1 g/L Pd(II) aqueous solution with 99,4% purity is obtained, from which palladium is directly isolated as dichlorodiammine palladium(II) salt (Pd(NH3)2Cl2) after precipitation with ammonia. Overall, palladium is quantitatively recovered from the leaching solution, and no palladium was detected in the remaining solid residue. Purity is high, as no contaminating metal could be detected in the final palladium salt. The proposed approach is simple and complementary to existing hydrometallurgical processes dedicated to gold and copper recovery.

中文翻译：

---

从印刷电路板废料中回收钯的简单工艺

摘要 详细介绍了一种从废印刷电路板 (PCB) 中回收钯的有效工艺。钯被用作多层陶瓷电容器 (MLCC) 的电极材料。这些组件可以通过脱焊轻松从 PCB 上移除。由于钯与银形成合金，因此使用稀硝酸很容易将其溶解。结果，获得了包含钯以及贱金属（主要是铜和铁）的溶液。然后使用基于 N,N'-二甲基，N,N'-二丁基十四烷基丙二酰胺 (BDMA) 的溶剂通过溶剂萃取 (SX) 处理该溶液，BDMA 是一种先前在废弃核燃料后处理框架中开发的强大的萃取分子。SX 序列期间产生的废水量是有限的：铁洗涤在水相与有机相的体积比非常低的情况下进行操作，钯的剥离不需要特定的金属螯合剂，也不需要从酸性介质到碱性介质的转变。最后，获得纯度为 99.4% 的约 1 g/L Pd(II) 水溶液，在用氨沉淀后，钯以二氯二胺钯 (II) 盐 (Pd(NH3)2Cl2) 的形式直接从中分离出来。总的来说，从浸出液中定量回收了钯，在剩余的固体残留物中没有检测到钯。纯度高，因为在最终的钯盐中没有检测到污染金属。所提出的方法很简单，并且是对现有专用于金和铜回收的湿法冶金工艺的补充。并且不需要从酸性介质到碱性介质的转变。最后，获得纯度为 99.4% 的约 1 g/L Pd(II) 水溶液，在用氨沉淀后，钯以二氯二胺钯 (II) 盐 (Pd(NH3)2Cl2) 的形式直接从中分离出来。总的来说，从浸出液中定量回收了钯，在剩余的固体残留物中没有检测到钯。纯度高，因为在最终的钯盐中没有检测到污染金属。所提出的方法很简单，并且是对现有专用于金和铜回收的湿法冶金工艺的补充。并且不需要从酸性介质到碱性介质的转变。最后，获得纯度为 99.4% 的约 1 g/L Pd(II) 水溶液，在用氨沉淀后，钯以二氯二胺钯 (II) 盐 (Pd(NH3)2Cl2) 的形式直接从中分离出来。总的来说，从浸出液中定量回收了钯，在剩余的固体残留物中没有检测到钯。纯度高，因为在最终的钯盐中没有检测到污染金属。所提出的方法很简单，并且是对现有专用于金和铜回收的湿法冶金工艺的补充。从浸出液中定量回收钯，剩余固体残留物中未检出钯。纯度高，因为在最终的钯盐中没有检测到污染金属。所提出的方法很简单，并且是对现有专用于金和铜回收的湿法冶金工艺的补充。从浸出液中定量回收钯，剩余固体残留物中未检出钯。纯度高，因为在最终的钯盐中没有检测到污染金属。所提出的方法很简单，并且是对现有专用于金和铜回收的湿法冶金工艺的补充。