Life cycle assessment (LCA) of a novel solid-state recycling process for aluminum alloy AA6063 chips via direct hot rolling

Aluminum utilization has been growing in the last decades thanks to its high strength to weight ratio, corrosion resistance, excellent plasticity, and good weldability. Recently, unconventional processes have been developed for aluminum recycling, called Solid-State Recycling (SSR), by avoiding melting process, allow to save up to 85% of energy needed for secondary aluminum production. The aim of this study is to assess the environmental advantages of a novel recycling technique namely Direct Hot Rolling process. This innovative solid state recycling process will be evaluated for its eco-friendliness. The Life Cycle Assessment (LCA) analysis follows a gate-to-gate approach: collected chips coming from prior cutting process are cold pressed and subsequently hot and cold rolled to obtain the functional unit, defined as the sheet produced through Direct Rolling of 35g of AA6063 chips. Primary data come from direct measurements provided by an industry plant operating in aluminum production field and direct measurements taken during the experimental activity in laboratory. Secondary data were provided by studies available in literature and SimaPro® databases. This LCA comparison between two similar different routes for SSR through rolling suggests that the second one, Direct Hot Rolling + ARB technique, is more suitable to reduce the environmental impact of aluminum recycle industry. However, Accumulative Roll Bonding is considered a low productivity process for worldwide industries, considering the difficulty of automation and repeatability of the procedure.