In the primary copper industry the electric furnace is an essential unit to recover Cu from the generated slag. Here the reduction of copper oxide and the settling of finely dispersed droplets take place. In particular, the kinetics of this reduction process plays a major rule. The theoretical part of this thesis gives an insight into the processes of slag formation in particular with regard to the formation of copper losses and into the processing of slag in the electric furnace. Kinetic studies on the reduction of copper slags have been carried out by R. G. Reddy, whose remarks are dealt with in a separate section. Within the framework of the practical experimental procedures, sulfidic and oxidic slag samples are reduced by an overstoichiometric amount of pig iron. This process takes place at a temperature of 1200 °C in an electrically heated resistance furnace, where no melting turbulence occurs. By using scanning electron microscopic evaluation, the respective reduction success for different times can be determined. As a result, statements concerning the kinetics during copper-recovery-melting are possible.