Gas-based Reduction Kinetics of Sintered Ilmenite Concentrate

In order to deeply understand the gas-based reduction mechanisms of sintered ilmenite concentrate,the isothermal reduction of the sintered ilmenite concentrate was performed under the reduction atmosphere of 30% CO and 70% N₂ at 800,900 and 1 000 ℃,respectively.And the reduction kinetics was analyzed.The reduction degree of iron oxides in the sintered ilmenite concentrate increased with increase of the reduction temperature and time,with a relatively low reduction degree of about 70%.At 800～1 000 ℃,the reduction was controlled by interface chemical reaction during most of the reaction period（＜140 min） of the sintered ilmenite concentrate with the activation energy of 46.97 kJ/mol,while it was predominated by diffusion in the last reduction period（＞140 min） with the activation energy of 99.27 kJ/mol.The main phase transformations during the reduction process can be described as follows:Fe₂TiO₅→Fe₂TiO₄→FeTiO₃.The particle size of metallic iron in the reduced sample increased from 4.46 μm to 30.13 μm with increase of the temperature under the same reduction time.