Recovery of Aluminum Alloy from Aluminum Dross by Treatment of Chloride-Fluoride Mixture Melt

A new process for recovery of aluminum from aluminum dross was developed. The aluminum dross which is obtained as a by-product during casting process of aluminum alloy contains aluminum alloy and oxides of various metals including aluminum oxide. The process consists of two stages: (1) Separation of the aluminum alloy from the oxides by difference in density between the alloy and the oxide in molten salts. (2) Dissolution of oxides into molten salts, and electrolysis of the molten salts to form metallic aluminum from the oxide. This paper is concerned with the first stage for the separation of the aluminum alloy from the oxides by using BaCl2-NaCl-NaF melts. The aluminum alloy completely separates from the oxides in the melts at concentrations of BaCl2 higher than 33.3 mol%, in which the liquid aluminum alloy floats up and the oxides sink down. From a 30 g dross sample, amount of about 24 g of aluminum alloy has been recovered. The remaining oxides contains aluminum oxide, silicon oxide, magnesium oxide and iron oxide. From the aluminum oxide dissolved in the melt, metallic aluminum is formed by electrolysis in a subsequent stage