The Influence of Pyrolythic Reactions on the Aluminum Dross Formation during the Twin Chamber Remelting Process

After a coated aluminum product has reached the end of life cycle it needs to be recycled in an economical way. State of the art is the thermal removal of the organic fractions by pyrolysis. In modern multi chamber furnaces this step is realized in a separate pre-heating and melting compartment of the furnace. The incidence of aluminum losses can be traced back to the contained organic components, which lead to an aluminum burn off and thus increase dross production. The influence of typical scrap package structures on the de-coating step and the impact of released organic components on the dross quantity are investigated in this work. Lab-scale experiments have shown that the average residence time is too short to complete the pyrolysis. It has to be considered that the pyrolysis continuous while the scrap bale is submerged in the aluminum melt.