From Waste Metallized Film Capacitors to Valuable Materials: Hexagonal Flake-Like Micron Zinc Powder, Copper–Iron Electrodes, and an Energy Resource

Metallized film capacitors (MFCs) are widely applied in electronic appliances. The rapid replacement of electronic products leads to producing a great many waste MFCs. Waste MFCs, containing organics (plastic dielectric and brominated epoxy resin) and metals (zinc, copper, iron, etc.), are not only considered as hazardous waste but also a valuable resource for recycling. However, how to recycle waste MFCs effectively is seldom considered. This work provided an integrated technology for recovering waste MFCs. First, waste MFCs were treated by pyrolysis to recycle the organics. The decomposition characteristic, product, and mechanism of the organics were studied. A pyrolysis temperature of 500 °C and holding time for 30 min were determined as the optimal parameters. Then, the residues were conducted by grinding and screening to recover copper–iron electrodes. Finally, hexagonal flake-like zinc powder with a particle size of 15 μm was recovered by vacuum metallurgy separation (VMS). The VMS principle for recovering zinc and the growth process of hexagonal flake-shape zinc powder were analyzed. The recovery rate and purity of zinc could reach 95.66% and 99.87%, respectively, at 650 °C and 100 Pa for 2 h. In short, our study contributes to the efficient and maximum recycling of waste MFCs.