Separation of iron-rich impurities in Al–10Si secondary alloy by pulsed electric current

Iron removal technology is a widely concerned technical challenge in the aluminum industry both domestically and internationally, as iron impurities are difficult to remove during the purification process and pose a significant threat to the material's performance. Adding chemical elements can change the morphology of iron phase, but generally cannot remove iron. Centrifugal separation method is complicated to operate and not suitable for industrial production, and the iron removal effect of other physical methods is not significant. Aiming at the bottleneck problem of grade protection and utilization of recycled aluminum, based on the theory of current density gradient, a separation method for impurity iron inside aluminum liquid using pulse current treatment was explored in this study. Within the industrial melting temperature range, impurity iron can be pushed to the lower part of the sample in a short period of time. Under the optimal pulse current processing parameters, the average iron removal rate of recycled aluminum exceeds 70.8 %, with locally highest iron removal rates exceeding 90.5 %. As an efficient, green, and energy-saving emerging purification method, pulse current can facilitate the migration, enrichment, and separation of iron rich phases, providing an innovative solution for industrial clean production of recycled aluminum.