THE FUNDAMENTAL KINETIC CHARACTERISTICS OF AQUEOUS DISSOLUTION OF CHLORIDE AND FLUORIDE SALTS FROM SECONDARY ALUMINIUM DROSS

The salt content in the secondary dross obtained alongside recovered aluminium through the hot processing of primary melting dross poses challenges for further material utilization. This study focuses on leaching secondary dross samples, derived from industrial processes of aluminium alloy scrap melting, with water at room temperature while varying the Liquid/Solid (L:S) ratios. Key insights were gained regarding vessel filling, which impacted result interpretation during the shaking bottle tests. Regular sample collections over a 15-minute window highlighted that sodium chloride (NaCl) and potassium chloride (KCl) dissolve almost instantly and completely regardless of the settings applied. Conversely, calcium fluoride (CaF2) displayed complex dissolution behavior linked to side reactions indicative of the conditions in the hot processing of the dross. Findings suggest that secondary aluminium dross salt content can be effectively leached within 2 to 4 minutes, contingent upon proper coordination of the L:S ratio and vessel filling. Observations indicate that at the lowest examined L:S ratio of 1.0, a maximum vessel filling of 11% is optimal for expedited salt dissolution. An equivalent dissolution rate is achievable with higher vessel filling and adjusted L:S ratios.