Kinetic study on gas molten particle reduction of iron ore fines at high temperature

Abstract

A kinetic study of gas molten particle reduction has been carried out using a high temperature drop tube furnace at the typical conditions of the smelting cyclone of the HIsarna ironmaking process. The results demonstrated that particle size has a significant effect on the reduction rate of fine iron ore particles and that the reduction ability of H2 is two to three times higher than that of CO at high temperature. It was found that almost all of the Fe2O3 in the iron ore particles was reduced to Fe3O4 and FeO in the first 210 ms. The morphology images of the partially reduced spherical particles showed that a liquid FeO product layer was formed outside the solid Fe3O4 unreacted core. The kinetic analysis revealed that the rate controlling step of the gas molten particle reduction was the diffusion of Fe3+ in the liquid product layer and that the activation energy was ∼156 kJ mol − 1.