Studies on Kinetics of Hydrogen Reduction of Different Diameter Ironsand Oxidized Pellets Containing Titanium

In this paper,the kinetic mechanism of reducing different sizes of Indonesia ironsand oxidized pellets by hydrogen was studied by means of gravimetrie method. The research mainly focuses on the kinetics. The results showed that the different reduction mechanism presents at different temperature. The restrictive step was composed of two different stages when reduction temperature was below 900 ℃,that is,the reduction begun with chemical reaction,and then was controlled by chemical reaction and intraparticle diffusion. When the temperature exceeds 900 ℃,The reduction mechanism was composed of three stages,that is,beginning with chemical reaction,followed by mixed-control of chemical reaction and intraparticle diffusion,and finally ended by intraparticle diffusion. At any reduction temperature,small oxidized pellets show a faster reaction speed at chemical reaction restrictive step,and have a smaller reaction resistance at intraparticle diffusion restrictive step.