Reduction of titania-ferrous ore by hydrogen

The reduction of titania-ferrous ore (ironsand) containing 57.2 mass% of iron and 7-8 mass% of TiO2 was investigated in isothermal experiments using H-2-Ar gas mixtures in a laboratory fixed bed reactor in the temperature range from 973 to 1373 K. The degree of reduction was measured using an on-line Dew Point sensor and the samples in the course of reduction were characterized using SEM and XRD analyses. The complete reduction of iron oxide in the ore by 25vol%H-2-Ar was achieved within 60 min at temperature higher than 1123 K. At 1173 K, the reduction rate increased with hydrogen content in the reducing gas up to 25vol%H-2. The composition of samples after 2-h reduction by 25vol%H-2-Ar depended on the reduction temperature. Below 1073 K, the final sample contained iron and iron-titanium oxides. At temperatures above 1173 K, the final sample was composed of iron and titanium oxide. The reduction path at temperatures above 1173 K is suggested as follows: Fe3-xTixO4 --> 'FeO' + Fe3-x-deltaTix+deltaO4 --> Fe + Fe3-x-deltaTix+deltaO4 --> Fe + xTiO(2), (0 < delta < 1 - x).