Plasma cleaning approach for recycling aluminum alloy machining chips

Sustainable manufacturing requires efficient, low environmental impact cleaning technologies for preparing metal chips for recycling. This study investigates a plasma cleaning approach for removing organic contaminants from complex-shaped AA7075-T6 machining chips, with the purpose of improving surface cleanliness and enabling more efficient solid-state recycling of high-strength aluminum alloys. The influence of plasma treatment parameters on cleaning performance was systematically evaluated using Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results show that the removal of organic surface residues is strongly governed by plasma power. Plasma cleaning efficiencies exceeding 80% were achieved at 30 W with short treatment durations, accompanied by a substantial reduction in surface carbon content. Higher power levels consistently provide more effective and uniform contaminant decomposition compared with extended treatment durations at lower power, even when the total energy consumption is similar. This demonstrates that instantaneous discharge power plays a dominant role in enabling efficient surface activation and contaminant removal. The findings offer guidance for selecting energy efficient plasma processing conditions and support the integration of plasma cleaning into future industrial recycling workflows. By reducing chemical usage and improving energy efficiency, the proposed approach contributes to broader Environmental, Social, and Governance (ESG) objectives, with a primary impact on the environmental dimension through enabling cleaner, safer, and more sustainable aluminum recycling practices.