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.

Keywords:

• HIsarna process
• Gas molten particle reduction
• Reduction kinetics
• High temperature
• Liquid product layer
• Solid unreacted core

Acknowledgements

This research was financially supported by the Materials Innovation Institute M2i (www.m2i.nl) under the project no. M41.5.09327. The authors would like to express their thanks to Mr J. van der Stel and Mr C. Treadgold from Tata Steel Europe (IJmuiden) for fruitful discussions and providing process data for this study. The first author acknowledges the China Scholarship Council (CSC) for providing the scholarship during this research at Delft University of Technology.