Cradle to Gate LCA analysis for wrought aluminum recycling process from high impurity content alloys with the fractional crystallization technology

An increasing demand for wrought aluminum, such as in the automobile field, requires the recycling of scraped aluminum into low-impurity-content wrought aluminum in an environmentally friendly manner. In this paper, the feasibility of the fractional crystallization method coupled with electromagnetic stirring (EMS) technology to obtain wrought aluminum high-quality alloys from high-impurity-content aluminum was reviewed. Also, a Cradle-to-Gate life cycle assessment (LCA) was conducted to assess the greenhouse gas (GHG) effect of this technology. Results indicate that, through this technology, the Al-rich phase was successfully separated from the impurity-rich phase. In LCA, an upscaling method was employed to assess GHG emissions. The results show that GHG emissions reduced as production scale increased. Also, GHG emissions between the lab and the pilot scales at the same production scale were compared; those extrapolated from the lab scale were notably higher. In addition, GHG emissions in an improved scenario were analyzed. At a 1,000 kg production scale, GHG emissions were 0.36 kg CO2 eq/kg, much lower than the GHG emissions of primary aluminum (9.93 kg CO2 eq/kg). The analysis showed that the fractional crystallization method with EMS technology is a promising technology for upgrading recycling from high-impurity cast alloys into low-impurity-content wrought aluminum alloys with very low GHG emissions.