Electro-Adhesion Force Applied to Metal Particles Using a Double-Sided Electrostatic Actuator

Electrostatic separation is a proven technique for the selective sorting of solid materials and is widely applied in recycling and waste valorization. Conventional methods, which rely on forces acting on charged or polarized particles, often face limitations in selectivity and efficiency when treating complex metal/plastic mixtures. This study introduces and investigates a novel device, the Double-Side Electrostatic Actuator (DSEA), designed to generate a specific electro-adhesion force acting on metallic particles.

The DSEA consists of a dielectric layer with segmented parallel electrodes on the top surface and a continuous plate electrode on the bottom side. This double-sided configuration allows the application of high-amplitude polyphase voltages without breakdown, thus improving performance compared to single-sided systems. The electro-adhesion force was quantified using an experimental setup that combined the DSEA with a suction aspirator placed 5 mm above the surface to evaluate particle retention under airflow.

Experiments were performed with monocomponent copper particles and with binary mixtures containing 70% copper and 30% PVC. The results showed that adhesion depends strongly on electrode geometry, with smaller widths and gaps leading to stronger retention. At 2000 V and airflow ≤1.3 m³/min, copper recovery and purity reached 100%, while all plastic particles were completely removed. Numerical simulations with COMSOL confirmed the concentration of the electric field at electrode edges, explaining the selective adhesion mechanism.

These results demonstrate the potential of the DSEA for efficient metal/plastic separation, combining high recovery with high purity, and provide new insights into advanced electrostatic recycling technologies.