Apparatus and method for removing alkali - and alkaline earth metals from the molten aluminum

摘要

For the removal of alkali metal and alkaline earth metal contaminants molten aluminium (including Mg-free aluminium alloys), is passed through an active bed of particles of material containing aluminium fluoride, maintained continuously immersed in molten aluminium. Alkali metal and alkaline earth metal contaminants react and may release insoluble molten reaction products. In order to avoid plugging of the active bed and achieve removal of molten reaction products the molten metal is preferably passed upwardly successively through an inactive filter layer, an active bed layer and a further inactive filter layer.