NEUTRAL, ACID AND ALKALINE LEACHING OF TYPICAL THERMO-MECHANICALLY TREATED ALUMINIUM MELTING DROSS RESIDUES

This study investigates the hydro-metallurgical treatment of aluminium melting dross residues which are primarily composed of oxide and have a negligible metallic content, rendering them unsuitable for further metallurgical processing. The objective was to find efficient leaching methods to remove harmful chloride salts and enhance the potential recycling and applicability of these residues in various industries. Methodologically, the researchers conducted a series of leaching experiments using pure water, sulphuric acid, and sodium hydroxide, assessing the efficiency of each treatment. The results revealed that water leaching effectively eliminated main salt components such as NaCl and KCl quickly, but released some ammonia due to reactions involving AlN formed during the residue's thermo-mechanical treatment. Leaching with sulphuric acid not only succeeded in reducing residual metal content but also mitigated ammonia evolution. In contrast, sodium hydroxide proved to be aggressive in dissolving aluminium but increased ammonia release. Based on the phase composition and structural analysis of the residues, the study concludes that water leaching, potentially followed by sulphuric acid treatment, can provide a satisfactory method for preparing residual dross for diverse applications.