Supergravity Separation for Cu Recovery and Precious Metal Concentration from Waste Printed Circuit Boards

Abstract

Printed circuit boards (PCBs) contain both valuable metals and hazardous materials, thereby rendering them attractive secondary sources of metals, but also environmental contaminants. Thus, we herein report the use of supergravity separation for the recovery of copper (Cu) and the concentration of precious metals present in waste PCBs. At an optimized temperature of 1300 °C, a gravity coefficient of 1000, and a separation time of 5 min, the total recoveries of Cu, Zn, Pb, and Sn over the whole separation process were 97.80%, 95.59%, 98.29%, and 97.69%, respectively. Compared with the amounts of precious metals present in the original PCBs, the contents of Ag, Au, and Pd in the Cu alloy increased by 5.16, 2, and 1.85 times, respectively, while those in the final residues increased by 2.92, 1.59, and 1.54 times, respectively. Upon combination of the appropriate hydrometallurgical process and supergravity separation of metals or alloys, this clean and efficient process provides a new way to recycle valuable metals and effectively prevent environmental pollution from PCBs.