Abstract
As aluminium (Al) recycling increases, the composition of minor elements in recycled Al fluctuates significantly. Trace elements in Al alloys can lead to serious defects; for example, the combination of copper (Cu) and zinc (Zn) can cause corrosion issues, even when the alloys produced from recycled scrap meet specifications. However, removing tramp elements from Al scrap remains a challenge. This study aims to eliminate impurity elements from Al by exploiting the high vapor pressure of those elements compared to molten Al. Laboratory experiments demonstrate that 11% of Zn can be completely removed by holding the material for 30 min at 800 °C or 120 min at 700 °C under a 0.1 mbar vacuum. The kinetics and thermodynamics of vacuum refining is also discussed.