The high copper consumption, driven by the economic development of the last 15 years, lead copper producers to focus specially on complex concentrates. This means for Aurubis AG to have the necessity for treating single concentrate with As-levels up to 0.50 % in the future. For this reason the maximum value of As in the concentrate mixture has to be adopted from 0.11 % to 0.20-0.30 %. The existing production technology cannot meet these needs without loss of quality, especially for the iron-silicate-product. In this work a treatment-process for flue dusts from the first stage of copper production was developed. The flue dusts obtained during the smelting process are normally recycled to the process due to their high Cu-Level which can reach up to 30 %. The balance of As distribution in the process showed that more than 50 % of the As-input to the smelter is derived from this massflow. The intensive study and characterization of the arsenic compounds in the flue dust formed the basis for the experimental investigation. The results showed that the main part of the Arsenic is present in form of copper and iron arsenate (73 %). The missing amount is distributed in almost equal shares to oxidic and sulfidic compounds. By adding a sulfur source under inert process conditions the removal of > 90 % of the available arsenic can be volatilized and stored in a safe, water stable, sulfidic form. The crucial parameter beside the process temperature is the S-content of the feed material. Different sulfur sources were tested and provided the result that concentrate fits best for this purpose. The next step showed that the application of mixtures of flue dust and concentrate is applicable for the treatment in a fluidized bed reactor. Based on this knowledge the flow-sheet including offgas-treatment was designed. First rough calculation of CAPEX and OPEX showed the feasibility of the developed process.