Microstructural changes on the reduction of imperial smelting furnace sinters

The reduction reactions of Imperial Smelting Furnace (ISF) sinter microstructure were investigated in simulated zinc blast furnace conditions. Initial and partially reduced samples were examined using optical, electron-probe microanalysis, scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), and X-ray diffraction (XRD) to characterize the struc-tural and compositional changes occurring during the reduction reaction. The reaction mecha-nisms and reduction sequences for the various oxide phases within the sinter structure during reduction of ISF sinters under the system studied are discussed. The reduction of sinters resulted in the structural modification of zincite, franklinite, slag phases, and the formation of new oxide and metallic phases. The rate and sequence of these complex phase transformations were found to be dependent upon reduction time, temperature, and the reacting gas composition.