Upgrading Recycle Technology for Iron Removal in ADC12 Alloy Using Gravity and Magnetic Force
摘要
As there is a technical issue to remove iron elements during aluminum recycling process, an attempt was made to evaluate the effectiveness of magnetic and gravitational separation methods for removing iron from Al-Si-Cu alloy (ADC12). A rare-earth samarium–cobalt (SmCo) magnet was employed during the solidification process to attract Fe-rich eutectic structures. The microstructural analysis revealed that block-like Fe-Cr-Si-based phases formed preferentially near the magnet and at the bottom of the crucible, suggesting that magnetic and gravity attraction contributed to the localized segregation of these phases. However, other Fe-based phases, including Fe-Si-based ones, are not strongly affected by magnet. Additionally, prolonged heating in the solid–liquid coexistence (SLC) region at 577 °C for 10 h led to the settling of a largely grown Fe-Cr-Si-rich crystal at the bottom of the crucible due to gravity. Other structures, such as Si-rich eutectic phases, were not influenced by gravity, which may be caused by the low density of Si compared to Fe one. From this approach, combining magnetic attraction and gravitational settling is a promising method to promote the removal of iron impurities from aluminum alloys.