De-ironing of Aluminium alloy scrap by high shear melt conditioning technology

Abstract

Aluminium scrap, with accumulated impurities such as Fe, is typically either downgraded to low quality cast products or diluted with expensive primary aluminium in order to reduce Fe concentration to under the allowed specification limits. However, the increasing demand of high quality components at affordable cost makes iron removal a major concern for the aluminium recycling industry. To address this problem, BCAST has developed an innovative technology, based on High Shear Melt Conditioning that enables low grade Al post-consumer crap, with high levels of Fe, to be transformed into a low cost and low carbon feedstock for high quality castings. It has been found that High Shear Melt Conditioning technology applied to aluminium scrap enhances the nucleation and growth of dense primary Fe–containing intermetallics. Due to their enhanced formation kinetics, these particles settle out rapidly allowing a simpler and faster removal of Fe from the melt. The developed iron removal technology is not limited to batch processing but can be applied to continuous melt treatment of aluminium scrap with high efficiency. The refined metal can be used in all casting processes reducing the need of primary aluminium, with the associated energy savings and impact on embodied carbon footprint.