Abstract
At end of life, waste PCBs (WPCBs) represent both a valuable resource—containing copper, nickel, precious metals, and polymeric materials—and an environmental hazard if landfilled or incinerated. This work develops and optimizes a modular, closed-loop recycling line that (1) delaminates epoxy resin from fiberglass and embedded metal via dimethyl sulfoxide (DMSO) extraction, comparing conventional thermal swelling with microwave-assisted processing to maximize resin yield, preserve fiber integrity, and assess solvent recyclability; (2) mills the residual PCB fragments under a design-of-experiments framework to tune particle size distribution (2–10 mm) and energy use, including evaluation of process-control additives; (3) fractionates milled material through sequential magnetic, eddy-current, electrostatic, and density separation, optimizing separation thresholds and recovering ferrous, non-ferrous, and non-metallic streams; (4) conducts hydrometallurgical extraction on the mixed metal fraction, including alkali pre-treatment, acid leaching (with oxidant enhancement), solvent-extraction, and electrowinning to produce high-purity metal products; and (5) scales the optimized processes from laboratory (2 L) to pilot (200 L) stirred reactors under geometric similitude. Finally, mass and energy balances, closed-loop solvent and water recycling. Key technical uncertainties—including solvent–resin selectivity, milling energy–liberation trade-offs, leaching kinetics in complex residues, scale-up hydrodynamics, and solvent recovery losses—are systematically investigated. The resulting platform offers a viable path toward circular, sustainable PCB recycling with minimized waste and maximized resource recovery.