Increasing amounts of heavy metal containing wastes from metallurgical plants force the legislation to increase landfill costs or even ban the disposal of these hazardous materials. However, with the removal of these wastes significant amounts of important metals such as zinc are lost. This is why several recycling methods for such materials have been developed. For example, the waelz kiln is the leading technology for the recycling of electric-arc-furnace-dusts, a typical heavy metal containing residue. Due to its simple design and relatively low investment costs, this method has become the established method in comparison to other pyrometallurgical and also partly available hydrometallurgical processes. Due to the use of fossil input materials in the waelz kiln process, significant amounts of CO2 occur. Since this gas is one of the green house gases, it leads to global warming. To change the process into a CO2-neutral one, the use of charcoal produced of biomass is being considered as alternative reducing agent. This work deals with the characterization of the produced charcoal from cutting wastes, in order to determine the most appropriate pyrolysis coke for this recycling process, which should replace the previously used fossil petroleum coke. For that reason, biomasses were converted into charcoals in a twin-screw-pyrolysis reactor, which were then investigated concerning their specific surface area and porosity as main parameters which influence the reactivity of such alternative reducing agents in the waelz-kiln.