Advancements in Mineral Processing and Metallurgical Techniques for Sustainable PCB Recycling: Opportunities and Challenges

The escalating volume of electronic waste, particularly waste printed circuit boards (PCBs), poses serious environmental challenges while offering substantial resource recovery opportunities due to their rich metal content. This critical review examines advancements in mineral processing and metallurgical techniques for sustainable PCB recycling. It analyses PCB sources, multilayered structures, and heterogeneous compositions, highlighting significantly higher concentrations of copper (12–29 wt%), precious metals (gold and silver), and base metals compared to natural ores. Preextractive mineral-processing techniques – including comminution, magnetic separation, density-based separation, electrostatic separation, eddy current separation, AI-based sorting, and froth flotation – are critically evaluated with quantitative benchmarking of recovery, energy consumption, metal losses in fine fractions, and practical limitations. When integrated with extractive methods (pyrometallurgy, hydrometallurgy, bioleaching, and eco-friendly thiosulfate leaching), these approaches achieve 92–97% copper recovery and 80–95% recovery of precious metals. Current industrial PCB recycling is dominated by dismantling, mechanical pretreatment, and integrated pyrometallurgical/hydrometallurgical routes. Three proposed conceptual flowsheets (low-budget Route I, large-capacity Route II, and high-purity Route III) illustrate how enhanced mineral processing can complement existing practices. Supported by industrial case studies (e.g. Umicore and Attero), thermodynamic and kinetic insights, life-cycle assessment, and techno-economic indicators (NPV/IRR), the review identifies both opportunities and persistent challenges such as fine-particle losses, high costs, and toxic emissions. Adopting a mineral-processing-centric framework, this review provides comparative insights and literature-based decision-support analysis, advancing a true circular economy by maximizing resource recovery and minimizing environmental harm, while highlighting key unresolved technical questions for future research.