Evolution of the structure and viscosity of copper slag during metallization-reduction

Oxygen-enriched smelting is accompanied by the precipitation of magnetite due to fayalite-based slag systems, which deteriorates the properties of slag and increases copper content in Cu slag. In this study, the evolution of the structure and viscosity of slag during metallization-reduction were investigated. The reduction process of the Fe-containing phase in Cu slag can be divided into two steps (Fe3O4→FeO, FeO→Fe) as coal dosage increases. In Fe3O4→FeO, the solid-phase particle content in Cu slag decreases, which simplifies the macromolecular structures, thus decreasing the viscosity of Cu slag. In FeO→Fe, the solid-phase particle content in Cu slag increases because of the formation of metallic Fe and Cu-Fe alloy particles. The macromolecular structures dominated by SiO4 and AlO4 tetrahedra become complex, increasing the viscosity of the Cu slag.