When considering the copper recovery in the primary industry, the electric furnace provides an essential unit for slag cleaning. From an economic point of view, a high metal output is necessary which is why studies concerning a possible improvement are carried out. This thesis gives an overview considering theoretical fundamentals of coagulation and separation of Cu-containing particles in an electric furnace slag. In addition, different tests are carried out on a corresponding slag from the company Aurubis AG. Particular attention is paid to the coagulation behavior of the copper particles. The coagulation is studied for various residence times as well as different types of bath movement and a comparison with resting slag is performed. Ultimately, a process recommendation, which leads to an improvement in the copper output from the slag, should be formulated.