FREMGANGSMAATE FOR FJERNING AV ALKALIMETALLFORURENSNINGER FRA SMELTET ALUMINIUM

摘要

A process for removing alkali metal impurities from molten aluminum while avoiding the emission of environmentally harmful gases and fumes. The process comprises introducing a sparging gas comprising a mixture of an inert gas and a gas selected from the group consisting of chlorine, fluorine, halogen-containing compounds and mixtures therefor into unalloyed molten aluminum while maintaining the concentration of halogen in the sparging gas at a value intended to selectively halogenate the alkali metal impurities at a sufficiently high utilization such that the concentration of chloride in the effluent gas is maintained below a predetermined permissible limit.