Electromagnetic separation of coarse Al–Si melts: The migration behavior of iron-rich phase and continuous growth of primary silicon

Abstract

5.5% Mn (mass fraction) was added as neutralizer in coarse Al–Si alloy produced by carbon electro-thermal reduction method which contained 5% iron (mass fraction). Al, Si, Fe and Mn particles were placed in the high-purity graphite crucible to be heated at 1400 °C for preparing the Al–Si-5 wt%Fe alloy. The separation mechanism and effects of Mn addition with electromagnetic directional solidification on the removal efficiency of Si and Fe were mainly investigated. Statistic data revealed that when mole ratio of Mn/Fe reaches 1.2 and a relatively low pulling down speed (10 μm/s) was adopted, Fe content was decreased to 0.42% and primary silicon can be well separated out and enriched at the bottom alloy, which meets the demands of casting Al–Si alloy. Since a desirable iron removal efficiency of 90% is obtained. The separation mechanism of Si and Fe from coarse Al–Si alloy using Mn by electromagnetic directional solidification is also deeply studied.