Recovery of Copper and Gold from Waste Printed Circuit Boards Using Monosodium Glutamate Supplemented with Hydrogen Peroxide

This study aimed to recover copper and gold from a waste printed circuit board (WPCB) using monosodium glutamate (MSG) supplemented with a clean oxidizer(s) under 30 ?, 150 rpm, and an initial pH of 7.00. The solder mask of WPCBs needed to be removed before leaching. At the first leaching, 93% of copper was selectively leached from solder-mask-free WPCBs within 3 h using 0.75 M MSG with 0.50% (w/?) H2O2. Then, gold (86%) was extracted from the first residue for 3 h by 1 M MSG with 0.25% (w/?) H2O2. In the downstream process, 98-100% copper could be directly recovered within 5-6 h from the first leachate by electrowinning (EW). However, gold in the second leachate required separation and purification processes before EW. At 4 h, 98% gold was adsorbed onto the activated carbon. Most impurities were removed from gold-loaded activated carbon by pre-elution using 0.05 M EDTA for 0.5 h without gold release. Afterward, 99% gold was eluted by diluted aqua-regia within an hour. Finally, the gold could be harvested perfectly using EW for 2 h. This complete copper and gold recycling process delivers an innovative concept for hydrometallurgical study and has the potential to develop into a practical industry.

Automated summary

This study focused on the recovery of copper and gold from waste printed circuit boards using monosodium glutamate (MSG) and clean oxidizers. The process involved leaching the copper and gold from the boards and subsequently separating and purifying the gold before electrowinning. The results showed a high percentage of recovery for both metals, showcasing the potential of this hydrometallurgical method in practical industry.