Novel Process for Tin Recovery from Waste Print Circuit Boards (WPCBs) by Selective Oxidation Roasting Under H₂O Atmosphere

Waste printed circuit boards (WPCBs) are crucial secondary resources that contain a large number of valuable metals (Cu, Sn, Ti, Ni, Ag, Au, etc.), which have enormous recovery value. Current methods of extractive metallurgy have been principally focused on recovering copper and precious metals, with tin being largely overlooked. However, research has shown that the oxidation of tin to SnO_(g) by H₂O_(g) is a viable option. This study presents a new process for selectively recovering tin from WPCBs via oxidative roasting under H₂O_(g) conditions. Thermodynamic analysis was used to investigate the transformation and regulation of metallic tin to gaseous SnO. It showed that tin could be highly selectively separated from WPCBs. The volatilization of Sn reaches 95.2% under optimal experimental conditions. In addition, copper and noble metals were enriched in the roasted residues and could be used for copper smelting.