Waste printed circuit boards are a major source of strategic materials such as platinum group metals since they are used for the fabrication of technological devices, such as hard drive discs, capacitors, and diodes. Because of the high cost of platinum, palladium, and gold (> 25 k€/kg), an economic and environmental challenge is their recycling from printed circuit boards that represent around 2% weight of electronic equipment. Hydrometallurgical treatments allow the recovery of these metals in solution, with a high recovery rate for a leaching liquor made of thiourea in hydrochloric acid. So as to develop an efficient recycling process from this leach liquor, one requires the speciation of these strategic metals, as well as their extraction and quantitation in the mixture. For this purpose, platinum, palladium, and gold were dissolved in model leach liquors made of hydrochloric acid and thiourea at low concentration. The identification of metal complexes was determined as a function of thiourea concentration (between 10 μmol/L and 10 mmol/L) by the combination of UV-visible spectrometry, cyclic voltammetry, and for the first time capillary electrophoresis. The electrokinetic method was then applied for the quantitation of trace metal analyses in leach samples from waste printed circuit boards reprocessing, demonstrating its applicability for industrializable recycling applications.

Graphical abstract

废印刷电路板是诸如铂族金属之类的战略性材料的主要来源，因为它们被用于制造技术设备，例如硬盘驱动器，电容器和二极管。由于铂，钯和金的高成本（> 25 k€/ kg），经济和环境挑战是它们从占电子设备重量约2％的印刷电路板中回收。湿法冶金处理可以回收溶液中的这些金属，而硫脲在盐酸中浸出液的回收率很高。为了从这种浸出液中开发出一种有效的再循环方法，需要对这些战略金属进行形态分析，以及对混合物中的萃取和定量。为此，铂，钯，将金和金溶解在低浓度的盐酸和硫脲制得的模型浸出液中。通过紫外可见光谱法，循环伏安法和首次毛细管电泳相结合，确定了金属配合物的鉴定与硫脲浓度（10μmol/ L至10 mmol / L之间）的关系。然后将电动方法应用于废印刷电路板再处理浸出样品中痕量金属分析的定量，证明了其在工业化回收应用中的适用性。并首次进行毛细管电泳。然后将电动方法应用于废印刷电路板再处理浸出样品中痕量金属分析的定量，证明了其在工业化回收应用中的适用性。并首次进行毛细管电泳。然后将电动方法应用于废印刷电路板再处理浸出样品中痕量金属分析的定量，证明了其在工业化回收应用中的适用性。

图形概要