Raffinering av magnesium og magnesiumlegeringer

摘要

The invention concerns a method for flux-free refining of magnesium and magnesium alloys where solid metal is melted by immersion in a melt of molten metal contained in a furnace (1) and filtered, wherein a stream of molten metal is passed upwardly through a layer of particulate filter material (9) contained in a filter insert (5, 6) by use of a pump (10). This pump can be arranged within the filter insert, above the filter material or in a compartment downstream of the filter. Alternatively, the solid metal could be melted in a separate furnace and transferred to the furnace containing the filter material. Preferably the filter material is made of steel or any material not reacting with molten magnesium. The openings in between the filter material should be much larger than the particles to be retained by the filter. It is preferred that the height of the filter layer is equal to or greater than the width of the filter insert.