Solid-state recycling of pure aluminum chips via direct hot rolling: mechanical, microstructural, and corrosion insights

This study presents a novel method for recycling aluminum chips through direct hot rolling, eliminating the need for conventional melting processes. The solid-state recycling (SSR) approach reduces energy consumption, minimizes material loss, and mitigates environmental impact. Chips of pure aluminum (99.9wt.%) produced by turning were compacted, heat treated and subjected to hot rolling. Both compacted chips and parent-bulk material underwent the same rolling schedule achieving the final thickness of 0.8 mm. The produced sheets were subjected to microhardness, tensile tests, microstructure analysis (optical and SEM-EBSD techniques), density measurements, and corrosion tests. The recycled sheets exhibited average mechanical properties close to those of the parent-bulk material, albeit with higher data dispersion, with an Ultimate Tensile Strength (UTS) of 94.6 vs. 94.4 MPa, elongation at fracture (A%) of 7.0 compared to 7.1%, microhardness of 26.2 vs. 28.4 HV respectively, and lower corrosion rate for recycled chips. Overall, the results demonstrate the fundamental feasibility of direct hot rolling as a solid-state recycling route for pure aluminum chips under controlled conditions.