The optimization of electrostatic separation systems is essential for increasing the recycling efficiency of electrical and electronic waste (e-waste) and supporting sustainable waste management. This work presents an innovative double-sided inclined electrostatic conveyor system, assisted by controlled vibrations, for separating aluminum–plastic composites from electronic waste materials. The device combines two complementary electrical mechanisms: electro-adhesion, which retains conductive aluminum particles through applied electric fields, and traveling-wave electric fields, which repel insulating plastic particles. Vibrations enhance particle mobility, limit agglomeration, and improve separation dynamics. A systematic optimization of the electrical system was performed using a three-level full factorial design (3²). Two operational parameters were selected: applied voltage (1.0, 1.5, and 2.0 kV) and conveyor inclination angle (20°, 30°, and 40°). The responses were aluminum purity and recovery efficiency. Eighteen randomized runs were carried out, and results were analyzed statistically by analysis of variance (ANOVA).
Experimental results confirmed that both voltage and inclination significantly affect separation performance. Increasing these electrical parameters improved aluminum purity, which reached 100% at 2.0 kV and 40°. Recovery efficiency remained consistently high, attaining 99% at optimum settings. The interaction between voltage and inclination was significant, highlighting the need to adjust these factors simultaneously. Regression models showed excellent predictive capability (R² > 98%), validating the design methodology's robustness. This study confirms the effectiveness of factorial design for optimizing electrostatic separation systems in electrical engineering applications. The identified optimal electrical operating conditions ensure maximum aluminum purity and recovery efficiency, offering practical perspectives for industrial recycling of aluminum–plastic waste from electrical and electronic equipment.
