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.