Pre-oxidation of ilmenite ores and its bearing on their solid-state reduction by hydrogen

Abstract

Oxidation of Abu Ghalaga and Black Sand ilmenite ores at various temperatures causes maximum weight increase of approximately 4% and 3.1% of ilmenite which values correspond to the oxidation of 75% and 88% of their FeO into Fe2O3, respectively. The magnetic proportions of oxidation products increase with rise of temperature up to certain values and then decrease, a fact which was not reported by previous investigators. Under certain conditions, concentration of iron in the magnetic fraction (52% and 54% instead of 39%) is possible. A mechanism is proposed for the oxidation including the formation of intermediate magnetic compounds of the type x Fe2O3. y FeTiO3. The net reaction representing postulated mechanism for A.G. ilmenite is 8 FeTiO3+ 3/2 O2 = 2 FeTi2O5 + 3 Fe2TiO5 + TiO2 and for B.S. is 16 FeTiO3 + 7/2 O2 = 2 FeTi2O5 + 7 Fe2TiO5 + 5 TiO2 . These equations agree satisfactorily with the results obtained as well as with the X-ray diffraction pattern acquired. Pre-oxidation of the ores provides products more susceptible to reduction with hydrogen than untreated ones up to certain temperatures characteristics for each ore. This is probably owing to some disturbance in the structure of the ores. (Dr. E.M. Khairy, Prof. of Chem., Chemical Dept., Faculty of Science, Cairo University; Dr. M. Kama Hussein, Head of Metallurgical Dept. and Mr. S.Z. El-Tawil, Research Fellow, Non-ferrous Metallurgy Unit, National Research Centre, Dokki, Cairo, U.A.R.)