The low grade secondary copper raw materials, which are used in the copper recycling, result in a significant input of further metals, like zinc, lead or tin. During processing, these contaminants are removed via various phases (dust, slag sludge etc.), where they are partly concentrated. In consequence, their reprocessing to generate marketable by-products, such as precious metals, nickel-sulfate, a lead-tin alloy etc. is justified. Therefore, modern copper secondary smelters are not only focused on the main metal, as various sub processes (e.g. a lead-tin-furnace for converter slag) allow a multi metal recycling. While most of the process residues are managed internally, the generated flue dust is sold directly to an external treatment. This means a loss of the contained metals copper, lead and tin, which actually could be recycled within a multi-metal-recycling, like the Kayser Recycling System (KRS). In the case of KRS, the discharge of these metals lead to a theoretical missed profit of about 7-22 m €, based on an annual dust formation of 20 000 t. The aim of the present study is to develop process concepts for an internal treatment of the generated flue dusts to enhance the ecology as well as the economy via an increase of the overall metal yield respectively the by-product quality. In principle, two different basic strategies can be used to fulfil these requirements. On the one hand the valuable fraction (lead, copper, tin) can be returned to the KRS by separating the zinc and the halogens. On the other hand the removal of disturbing elements like halogens from the flue dust leads to an increase of quality so that a potential secondary raw material for the zinc primary industry is produced. A successful process development is strongly connected to the knowledge about the particular material, which should be treated. Therefore, this work presents also fundamental principles for dust generation in the recycling as well as a detailed characterization of the considered material. The removal of disturbing elements can be carried out by selective leaching with soda addition or via partial vaporization. The results of the first procedure are not satisfying, as the halogen limits for an usage in the zinc primary industry were not reached. Nevertheless, based on a principal removal and the formation of easy recoverable bromine, this treatment is of interest for the recycling as a sub-process. In contrast, the selective vaporization at 1100 °C offers very suit-able results, as halogens and lead are removed almost completely. Therefore, the remaining material can be processed in the zinc primary industry, while lead is returned to the KRS and bromine is concentrated in a solution by soda leaching. Through this process copper and tin are also discharged to the zinc industry, why it is not suitable, if high amounts of these metals are present in the flue dust. For this purpose a separation of zinc and halogens by reduction and vaporization or selective leaching can be carried out. Both processes present positive results, although the hydrometallurgical treatment offers better yields. Nevertheless, the assembling of complex hydrometallurgical processes in predominantly pyrometallurgical plants, like copper recycling, is often difficult.