Carbothermic Reduction Kinetics of Oxidized Panzhihua Ilmenite Concentrate

The isothermal carbothermal reduction of oxidized ilmenite concentrate/carbon composite pellets was performed with coke as reductant,and the kinetics was analyzed by integration method. The reduction temperature was set at 1 000,1 100,1 200 and 1 300 ℃,respectively.The reduction degree of iron oxides in the oxidized ilmenite concentrate,able to be 91%,increased with increase of the reduction temperature and time.The reduction of oxidized ilmenite concentrate was controlled by interface chemical reaction in early stage of solid state reaction（ ＜60 min） with activation energy of 51.23 k J/mol at 1 000 ~1 300 ℃,while it was controlled by diffusion in later period（ ＞ 60 min） with activation energy of 93.53 k J/mol. The main phase transformation during the reduction process can be described as follows: Fe₂TiO₅→ Fe₃Ti₃O₁₀→FeTiO₃.During the phase transformation,the particles’ inner pore and specific surface area were increased,the gas diffusion conditions were improved and the chemical reaction rate in early stage was accelerated.