A Study of Non-isothermal Reduction of Iron Ores

Abstract

Studies of iron oxide reduction are quite many, and the mechanism and kinetics of reaction have also been reported. Many of these reports, however, are concernei with the iso-thermal reductions, and only a few reports on the non-isothermal reduction have been published. Then, the authors investigated the reduction of non-isothermal type; from room temperature to 1050°C by simple H₂ gas and mixed gases which approximate the distribution of gases in the B.F.
Moreover, a non-isothermal fluidized bed reduction was tried, and an empirical formula n=γ₀-γ₀ (ΔF/RT²) dT/dtΔt was presented and analyses were performed by this formula.
The results are as follows.(1) The non-isothermal reduction in comparison with isothermal case is quick to finish the reduction.(2) In the reduction by mixed gases of CO, CO₂, and H₂ the effect of reducing temperature is greater than that of the concentration of CO.(3) The non-isothermal fluidized bed reduction is possible up to near 1000°C without sintering of reduced powders.(4) The rate of non-isothermal reduction can be expressed as n=γ₀+γ₀ (ΔF/RT²) dT/dt·Δt.