Secondary Resource Utilization of Electronic Waste: a Review of Extraction and Recovery of Precious Metals

The amount of E-waste worldwide is rising year by year, approaching 60 million tons in 2022. The grade of precious metals (Au, Ag, Li, Pt, etc.) contains in E-waste is dozens or even hundreds of times that of traditional mined ores. However, the rapid growth of E-waste and its serious environmental impact have made it a worrying urban mineral resource. At present, the secondary recycling of E-waste resources is not recyclable. Although the traditional metallurgical process has certain application in the field of E-waste recycling, it is far from enough in the face of complex E-waste needs. This manuscript focuses on the separation of metal and non-metal components in E-waste, including disassembly, magnetic separation, electrical separation, flotation, and pyrolysis, then, through pyrometallurgy, hydrometallurgy, biometallurgy, supercritical fluids, and ionic liquids technology to recover the process of precious metals. Finally, the sustainable treatment and recycling technologies of E-waste in the future are prospected.