Reduction behavior of iron ore by reducing gas containing H2 S.

Effects of hydrogen sulfide (1–3%) on the reduction rate of iron oxide pellets were investigated in temperature range of 800–1100°C. It was found that the reduction rate increased slightly with the addition of 1% H2 S, whereas it decreased significantly with the addition of 3% H2 S. The fractured surface of partially reduced pellets was observed by an optical microscope, a scanning electron microscope (SEM) as well as analyzed by an energy dispersion spectrometer (EDS). It is indicated that small amounts of sulfur may have promoted the formation of porous iron to accelerate the reduction rate, whereas the dense iron sulfide shells formed at higher H2 S offered resistance to the intraparticle diffusion of reducing gas to significantly decrease the reduction rate of pellets. [ABSTRACT FROM AUTHOR]