All the carbon-coated iron ore samples were prepared by reducing the iron ore under the same pre-reduction condition, i.e., 1.5 L/min CO-H2 mixture gas with H2 mole fraction of
0.733 at 650 °C. Fig. 2 shows the corresponding pre-reduction rate and
carbon deposition rate. And the umf of such carbon-coated iron ore is
in the range of 3.0–3.8 cm/s, depending on its composition.