Hydrogen Reduction of Natural Ilmenite in a Fluidized Bed.

Abstract

The reduction of Australian ilmenite was carred out in a bubbling fluidized bed with pure hydrogen. It was found that the reduction did not proceed topochemically with respect to each grain due to its small size and porous characteristics, but the experimental data fitted the volume reaction model expressed by the following equation. –ln(1–x)=kvcgt kv=0.0299 exp[–61.0×103/(RT)] The reduction mechanism and rate constants obtained were applied to the mathematical model of a fluidized bed developed on the basis of two-phase theory for analyzing the rate limiting processes. Results of theoretical analysis showed that the mass balance of the reduction of ilmenite occurring in a fluidized bed operated in batches was described under the unsteady-state assumption. It was further found that both the mass interchange of the reactants between the two phases and the intrinsic chemical reaction played important roles as rate-limiting steps during the reduction of ilmenite.