Recovery of aluminum alloy from aluminum dress by treatment of chloride-fluoride mixture melt

A new process for recovery of aluminum from aluminum dress was developed. T he aluminum dress which is obtained as a by-product during casting process of aluminum alloy contains aluminum alloy and oxides of various metals incl uding aluminum oxide. The process consists of two stages: (1) Separation of the aluminum alloy from the oxides by difference in density between the al loy and the oxide in molten salts. (2) Dissolution of oxides into molten sa lts, and electrolysis of the molten salts to form metallic aluminum from th e 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 alum inum alloy completely separates from the oxides in the melts at concentrati ons of BaCl2 higher than 33.3 mol%, in which the liquid aluminum alloy floa ts up and the oxides sink down. From a 30 g dress sample, amount of about 2 4 g of aluminum alloy has been recovered. The remaining oxides contains alu minum oxide, silicon oxide, magnesium oxide and iron oxide. From the alumin um oxide dissolved in the melt, metallic aluminum is formed by electrolysis in a subsequent stage.