Hydrometallurgical Recovery of Copper from Computer-Printed Circuit Boards

¹ School of Chemical Engineering, College of Engineering, Universiti Teknologi MARA Johor Branch, Pasir Gudang Campus, 81750 Bandar Seri Alam, Masai, Johor, Malaysia
² Department of Chemical Engineering, Faculty of Chemical & Energy Engineering, Universiti Teknologi Malaysia, UTM Johor Bahru, Johor 81310, Malaysia

^* Corresponding author: wanfazlina@uitm.edu.my

Abstract

Modern electronic devices contain up to 60 different metals, leading to a growing interest in exploring secondary sources, particularly electronic waste (e-waste), to address potential shortages. This study focused on extracting copper (Cu) and gold (Au) from three different sources of computer-printed circuit boards (PCBs): board, USB jack, and capacitor. Aqua regia, a mixture of 68% concentrated nitric acid and 37% concentrated hydrochloric acid in a 1:3 ratio (HNO₃=1:3), was used as a leachant under various conditions, including different types of e-waste components, leaching times, and surface areas. Acidic leaching with a 1% (w/v) e-waste pulp density resulted in higher Cu extraction from PCB board waste compared to USB jack and capacitor waste. The optimal recovery of Cu achieved was 2207 mg/L after 20 minutes of leaching, using a particle size of 10 mm, at 100°C, 150 rpm, and a pulp density of 1% (w/v). The dissolution of Au was only traceable in the capacitor and USB jack with significantly lower quantities of 0.4 and 3.2 mg/L, respectively. Additionally, the electrowinning process managed to recover Cu with just 31.6% purity after one hour of electrolysis. In conclusion, this study demonstrates the feasibility of recovering valuable metals from e-waste through acid leaching, without the need for additional chemical treatments.