Pyrometallurgical processes invariably yield large amounts of fine residues containing high grades not only of valuable elements but often also of detrimental ones. A vast amount of publications is available on recycling these dusts, whereof the majority deals with the residues in their original state only. This, however, often does not suit the metallurgical process. A more cost-efficient alternative to being disposed of entirely may be their beneficiation by means of mineral processing techniques in order to render them recyclable. Systematic design of the processing flow sheet requires proper characterisation of the dusts’ relevant properties. Therefore a range of residues from iron and steel production was subject to fractional analysis. As a common finding, magnetic separation is not able to split the valuable elements jointly from the detrimental ones in these samples. Instead, all samples revealed a distinct relationship between particle size and composition. In some cases this trend was strong enough to provide air classifying with that desired effect of separation. Due to the typically fine particle size distribution of the residues, the methods of fractional analysis well established in mineral processing require some adaptation to serve these applications. Portability of the entire approach onto other metallurgical areas and other types of business is presumed.