Magnesium is considered as impurity element in aluminum recycled for obtaining some cast alloys, with low concentration Mg, because at 0.1 wt% results in fragility, fractures, and defects. This research applies the aluminothermic reduction process to decrease magnesium content in aluminum cans by adding ZnO, to produce reaction products solid-state (Al2O3, MgO and MgAl2O4), and there is a possibility to obtain Al-Zn alloy. The conditions of the process were, melting temperature (750, 800, 850°C) and stirring velocity (200, 250, 300 rpm). The Mg and Zn contents were measured for chemical analysis and scrap generated from every process was analyzed by X-ray diffraction. The results show how the aluminothermic reduction decreased Mg from 0.93 to 0.06 wt% and increased zinc up to 5.52wt % in the molten metal. Therefore, this process can be used to remove Mg and can also prevent the generation of polluting gases into the environment.
Part of the book: Aluminium Alloys