CHARACTERIZATION AND COMPLETE UTILIZATION OF ALUMINIUM MELTING DROSS

Aluminium scrap is a raw material of growing importance in the production of aluminium and its alloys. Due to the thermodynamic properties, melting the recycled metal of high specific surface generates significant amounts of dross consisting of an oxide matrix and a large proportion of entrapped liquid metal. This heterogeneous material is usually processed by a thermo-mechanical treatment with the addition of a large amount of NaCl-KCl based salt to recover the entrapped metal. The residual dross is currently considered as waste, and it is usually disposed of despite its potentially valuable metallic and non-metallic components. We have examined the structure and composition of different residual dross types applying instrumental techniques and chemical leaching tests. The results pointed out the possibility of utilizing the chloride and the oxide components and removing the still remaining metals. A method of hydrometallurgical processing has been examined for the recycling of the basically NaCl-KCl salt content leaving a residue which may be suitable as an additive to rough ceramic materials used in the construction industry.