The oven tests showed that physical, thermal and chemical factors
may promote metallic aluminum losses. In order of decreasing
impact the main factors were the packaging type, combustion temperature,
residence time and salt contamination. Waste contaminations
such as basic conditions and the Mg content of a packaging
alloy typically decrease the metal recovery rate by a few percent.
The size of the input packaging waste also proved to influence the
metal loss rate which was higher for smaller samples. As yet no satisfactory
explanation could be found for this size effect.