Effects of Cr2O3 content on viscosity and microstructure of copper converter slag

•The viscosity of copper converter slag was investigated using the rotating method in air atmosphere.•The viscosity of copper converter slag increased with Cr2O3 additions.•The free running temperature and activation energy of the molten slag increased with increasing involvement of Cr2O3.•Raman spectra analysis demonstrated that silicate network structure components of the molten slag samples converted from Q0 ([SiO4]4−, monomer) / Q1 ([Si2O7]6−, dimer) to Q2 ([SiO3]4−, chains) / Q3 ([Si2O5]2−, sheets). The influences of Cr2O3 on the viscosity of copper converter slag were investigated employing the rotating method in air atmosphere. The free running temperature was determined according to the viscosity-temperature curve and the activation energy was calculated based on Arrhenius-type relationship. The molten slag microstructure evolution was researched by Raman spectroscopy and Fourier Transform Infrared spectroscopy (FTIR). The results showed that the viscosity, free running temperature as well as activation energy increased significantly after the addition of Cr2O3. The viscosity of the original slag was 0.464 Pa·s at 1573K, exceeded 8.000 Pa·s after 5 wt% Cr2O3 being incorporated. Meanwhile, the Raman spectrums demonstrated that silicate network structure components of the molten slag samples converted from Q0 ([SiO4]4−, monomer) / Q1 ([Si2O7]6−, dimer) to Q2 ([SiO3]4−, chains) / Q3 ([Si2O5]2−, sheets), which indicated the formation of more complex structures and finally contributed to the increase of the viscosity. The influence mechanism of Cr2O3 on the copper converter slag viscosity and microstructures were uncovered to give reference for understanding the excellent slag resistance property of Cr2O3 containing refractories used in copper smelting furnaces.