Aurubis operates a network of primary and secondary smeltersSmelter to recover a large variety of metalsMetal. Regarding the fact that the range of raw materials is growing, and material compositions will become more complex, it is essential to understand how this impacts the production. The main target of this project was to gain further knowledge about the solubilitySolubility behavior of zirconium dioxideZirconium dioxide in primary copper smeltingPrimary copper smelting and converting processes. A further step was to investigate the kineticsKinetics behavior of the material. For the solubilitySolubility experiments, the slagSlag was melted in a ZrO2 crucible at 1250 °C and quenched samples were taken at regular intervals during the process. Additionally, a fixed oxygen partial pressure was set (average pO2 in FSF). The samples showed a maximum solubilitySolubility of 0.7–0.8% of zirconia in slagSlag, which was reached after at least two hours. For the kineticsKinetics tests, the samples were melted in a resistance-heated furnaceFurnace at 1250 °C. ZrO2 was mixed with slagSlag and the behavior of the material was investigated in converter (slagSlag blow) and FSF slagSlag. Within the first 30 min, the main part of the material is dissolved in FSF slagSlag and compared with the converter slagConverter slag the dissolutionDissolution process is faster.