Kinetics of the Oxidation and Reduction of Synthetic Ilmenite.

The kinetics of the oxidation and reduction of synthetic ilmenite was studied thermogravimetrically in the light of kinetic theory for heterogeneous noncatalytic reactions. It was found that the oxidation and reduction proceeded topochemically and their kinetic parameters were determined according to the unreacted core shrinking model. The mineral composition of the partially oxidized and/or reduced ilmenite was examined by means of characteristic X-ray analysis, the results of which showed that there were two phases in the oxidized ilmenite which separated each other. One of them was rich in titanium and the other was rich in iron. There were two phases too separating completely in the reduced ilmenite, one of which was the metallic phase consisting of almost pure iron and the other was an oxide phase mainly composed of titanium dioxides. The composition of the titanium-rich phase in the oxidized ilmenite was between the composition of Fe2O3·TiO2 and that of Fe2O3·3TiO2.