A sequential leaching procedure for efficient recovery of gold and silver from waste mobile phone printed circuit boards. (November 2022)

• Record Type: Journal Article
• Authors: Zhang, Zhi-Yuan; Wu, Lixiang; He, Kai; Zhang, Fu-Shen
• Is Part Of: Waste management. Volume 153(2022)
• Page Start: 13
• Page End: 19
• Publication Date: 2022-11
• Subjects: Waste mobile phone -- Waste PCBs -- Cuprous chloride -- Precious metal recovery; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2022.08.011
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: An eco-friendly technology for precious metal recovery was developed. Ag/Au enrichment and CuCl synthesis were achieved in one step. CuCl synthesis process promoted recovery of Ag and Au. Leaching of Au and Ag was achieved under mild conditions. Less reagents and time were required for Au and Ag recovery. Abstract: The present study reports a sequential, non-acid process for effective recovery of copper and precious metals from mobile phone printed circuit boards. In this process, gold and silver were first enriched during the synthesis process of cuprous chloride and then leached by thiosulfate method. Results indicated that the distribution of gold and silver in the liquid and solid phases during the synthesis of cuprous chloride process was affected by the [Cu]/[Cu 2+ ] ratio. Enrichment of gold and silver in the residue after the cuprous chloride synthesis could be achieved by the adjusting the [Cu]/[Cu 2+ ] ratio. The silver and gold leaching rates of the residue after cuprous chloride synthesis (93.8 % silver and 99 % gold) were much higher than those of the raw PCB sample (27.0 % silver and 14.2 % gold) under the same conditions. This process has the advantages of high leaching efficiency, high leaching rate and avoiding the use of HNO3 or aqua regia commonly used for copper, gold and silver recovery. Thus, this study offers a promising and environmentally friendly method for recovering valuable metals from e-waste.