Enhanced reduction of ilmenite ore by pre-oxidation in the view of pore formation

Abstract

The promotion effect of pre-oxidation on reduction of ilmenite was revealed from the view of pore formation. The result shows that the enhancement of pre-oxidation on reduction of ilmenite ore is attributed to the formation of porous structure during the reduction process. Reduction of ilmenite is inhibited by iron-rutile topology structure formed on the particle surface. By contrast, porous structure ilmenite is regenerated during the ferric-to-ferrous reduction stage of the pre-oxidized ilmenite with dominant reduction rate over diffusion rate of produced ferrous ω ≥ 33.2 mol/m4. The newly formed porous structure ilmenite enlarges particle surface area with facilitated gas-solid contact, thus it is responsible for the enhancement of the reduction of pre-oxidized ilmenite. A novel formation mechanism of porous structure is also proposed based on the competition and coordination between the reduction rate and diffusion rate determined by reduction potential and temperature.