Reduction of titania-ferrous ore by hydrogen

摘要

The reduction of titania-ferrous ore (ironsand) containing 57.2 mass percent of iron and 7-8mass percent of TiO_2 was investigated in isothermal experiments using H_2-Ar gas mixtures in a laboratory fixed bed reactor in the temperature range from 973 to 1 373 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 percent H_2-Ar was achieved within 60min at temperature higher than 1 123 K. At 1173 K, the reduction rate increased with hydrogen content in the reducing gas up to 25vol percent H_2. The composition of samples after 2-h reduction by 25vol percent 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: Fe_(3-x)Ti_xO_4 -> 'FeO' + Fe_(3-x-(delta))Ti_(x+(delta)O_4 -> Fe+Fe_(3-x-(delta))Ti_(x+(delta))O_4 -> Fe+xTiO_2, (0