High purity salt flux composition and additive composition, which is used in the melting of scrap aluminum such as found in used beverage containers, have been optimized in this investigation. Results indicated that the use of temperatures from 450 to 950C and flux amount of at least 5 wt.% lead to good recovery of aluminum after the recycling of cans. Utilization of chlorides and fluorides in excess result in formation of craters and dendrites in the recovered metal, which denote that the magnesium and aluminum oxides in the form of drosses, a heterogeneous system, accumulate in these craters. A visual examination of the images shows visible holes which provide continuous channels to the internal surfaces of the metal to the atmosphere. It is observed that the oxidation of the internal surfaces and channels result into huge amount of drosses. The molten chlorides and fluorides in excess corrode this structure and break the oxide links, subsequently liberating the pure aluminum.
Shakila Begum
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