Simultaneous Removal of Silicon and Iron Rich Phases from Coarse Al Si Alloys Using Manganese Under Electromagnetic Field
Coarse Al Si alloy is produced from bauxite via carbon electro thermal reduction method. Silicon and iron rich phases are two main detrimental impurities in coarse Al Si alloy, and they can be simultaneously removed by adding Mn under the electromagnetic field. We focus on the influence of different Mn additions, dropping rates, and current intensity on the simultaneous removal efficiency of Si and Fe. Experimental results show that as mole ratio of Mn/Fe reaches more than 0.8, the morphology of iron rich phases together with silicon changed from harmful acicular like to the contributing bulks, concentrated at the bottom of Al Si alloy as intermetallic compounds. Furthermore, when Mn/Fe reaches 1.2 and a lower dropping rate (5 to 25 mm/s) is adopted, both Si and Fe contents in the Al Si alloy decreased drastically after electromagnetic directional solidification process, reaching 11.42 and 0.4 pct, respectively, with a desirable Fe removal efficiency of 91 pct. Finally, the principle of simultaneously separating Si and removing iron rich phases from Al Si alloy is studied deeply.
Metallurgical and Materials Transactions B