Treatment of aluminium in a smelting furnace, incorporates a phase of reducing the oxidation of the molten aluminium

摘要

Material containing aluminium and possibly other salts is introduced to a furnace and melted by heat provided from a burner, fed with a fuel and a combustion agent, to produce molten aluminium covered with a slag of alumina and a salt. The concentration of carbon monoxide and/or hydrogen in the furnace atmosphere or in the fume leaving the furnace is measured. The combustion agent includes at least 10 %, and preferably in excess of 21 % by volume of oxygen. The treatment includes a final phase of reducing the oxidation of the molten aluminium during which the flow of combustion agent is essentially constant whilst the flow of fuel injected into the burner is a function of the measured concentration of carbon monoxide and/or hydrogen or vice versa, the concentration being regulated to a consigned value (C2) of between 3 and 15 % by volume.