GHG impacts of an innovative separation process (three-way sorting process) for horizontal recycling of aluminum

Life Cycle Assessment (LCA) was conducted in screening wrought aluminum from shredded automotive scrap using sorting technology. This technology comprises Pre-sorting, ECS (Eddy-current separation) sorting, and LIBS (Laser Induced Breakdown Spectroscopy) sorting, referred to as three-way sorting. Shredded automobile scrap contains wrought aluminum, cast aluminum, zinc, plastics, and other materials. Three-way sorting initially screens non-aluminum by Pre-sorting and ECS sorting, followed by LIBS sorting to separate wrought and cast aluminum. LCA showed that greenhouse gas (GHG) emissions to obtain wrought aluminum from the scrap were 0.168 kg-CO2 eq/kg. Further, GHG emissions decreased to －0.24 kg-CO2 eq/kg if reclaimed cast aluminum was reused and its GHG emissions were credited. Since GHG emissions of virgin aluminum were 9.93 kg-CO2 eq/kg, GHG emissions by three-way sorting were far below. In terms of cost, it was initially 259 JPY/kg to produce reclaimed wrought aluminum. However, under an improved scenario reflecting real manufacturing conditions, the study showed a potential to reduce its cost to 107 JPY/kg.