Recycling of aluminium swarf by direct incorporation in aluminium melts

The purpose of this work was to recover a standard AlSi12Cu1 alloy from machining chips inside the foundry plant, by using an environmentally friend technique to produce cast ingots with characteristics similar to those of the commercially available 2nd melt raw material. The recyclability of aluminium swarf using different melting techniques and the influence of chips preparation in the aluminium alloy recovery rate and dross production was experimentally studied and evaluated. It is shown that the recycling efficiency depends on the swarf conditioning for melting, the melting technique and the metal treatment methodology. Chips moisture reduction, induction melting under protective atmosphere and a specially developed degassing technique were found the most important factors influencing the recycling process. By using the developed technique, cast ingots with microstructure, sanity and chemical composition similar to commercially available AlSi12Cu1 2nd melt raw material were successfully obtained with minimum dross formation and metal recovery rates around 90%, without using traditional salts and fluxes.