Selective separation of metals from waste printed circuit boards using supergravity-assisted liquation technology

Abstract

Waste printed circuit boards (WPCBs) are the most crucial components of electronic waste，containing high-value metals that are attractive secondary sources and main recycling targets. This study proposed a combined method of supergravity technology and liquation technology to separate metals from WPCBs. Fe-rich, Cu–Zn and Cu–Sn phases were gradually precipitated and separated in supergravity fields. Two key parameters of separation temperature and gravity coefficient were investigated under different conditions. The optimum temperature was 1100 °C for separating Fe-rich alloy, and 800 °C for separating Cu–Zn and Cu–Sn alloy. Moreover, controlling the gravity coefficient at 600 in this study was deemed the most appropriate and energy-efficient. Under the optimum conditions, the mass fractions of Fe, (Cu + Zn), and (Cu + Sn) in Fe-rich, Cu–Zn, and Cu–Sn alloy reached 81.8 wt%, 95.0 wt%, and 89.9 wt%, respectively. A potential industrial apparatus for the novel method was also proposed. The results demonstrate that the proposed supergravity-assisted liquation method is a promising and optimized approach for selectively separating metals from WPCBs.