EAF Carbothermic Co-Reduction of Alumina and Silica for the Direct Production of Al-Si Master Alloy

摘要

A key alternative for primary aluminum production could be the carbothermic reduction of alumina. Developed concepts face problems with the high solubility of carbon in liquid aluminum, the presence of the oxycarbide slag and the high volatilization of aluminum at elevated processing temperatures. In order to overcome some of these obstacles, in the framework of the ENEXAL FP7 project, research into the co-reduction of alumina and silica was made, aiming at the direct production of Al-Si master alloys. The latter are key commercial products for all casting applications, accounting for approximately 30% of all aluminum demand. As predicted by the thermodynamic study and verified by lab scale EAF experiments, the presence of silicon in the system suppresses volatilization phenomena, limits the oxycarbide slag formation and reduces carbon solubility in the metal phase.