Solubility Behavior of ZrO₂ in Primary Copper Slags

Aurubis operates a network of primary and secondary smelters to recover a large variety of metals. 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 solubility behavior of zirconium dioxide in primary copper smelting and converting processes. A further step was to investigate the kinetics behavior of the material. For the solubility experiments, the slag 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 solubility of 0.7–0.8% of zirconia in slag, which was reached after at least two hours. For the kinetics tests, the samples were melted in a resistance-heated furnace at 1250 °C. ZrO₂ was mixed with slag and the behavior of the material was investigated in converter (slag blow) and FSF slag. Within the first 30 min, the main part of the material is dissolved in FSF slag and compared with the converter slag the dissolution process is faster.