CRYSTALLISATION METHOD FOR THE PURIFICATION OF A MOLTEN METAL, IN PARTICULAR RECYCLED ALUMINIUM

• Main Authors: WOUTERS, HUIBRECHT, ADRIAAN, BOENDER, WILLEM, HOGENBOOM, MARCELLUS, ALBERTUS, STORM, JOOST, CHRISTIAAN, BEUNDER, ELISABETH, MARIA, TEN CATE, ANDREAS, KIEFT, RENE
• Format: Patent
• Language: English; French; German
• Published: 28.07.2010
• Subjects: CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

Method for purifying molten metal having a specific density and including one or more foreign elements to be removed, by (a) cooling the molten metal to a eutectic temperature to simultaneously form purified metal crystals and crystals including at least one foreign element, and (b) separating at least some of the purified metal crystals from the crystals including at least one foreign element by adjusting the molten metal specific density within a range delimited by a lower value being specific density of the purified metal crystals and an upper limit being specific density of the crystals including the at least one foreign element. The molten metal specific density is adjusted to this range by addition of a metal to alter the molten metal specific density and maintained within this range during separation. The method is advantageously applicable for purification of aluminium melts from recycle aluminium and aluminium scraps.