A mathematical model of a ported, kiln for iron oxide pelletizing was developed to simulate the effects of under-bed air injection on kiln fuel requirements and magnetite oxidation. A tanks-in-series model was used to set up material and energy balance equations for countercurrent flow,of solids and-gas through the kiln, The diffusion-limited, shrinking core model was used magnetite oxidation reaction kinetic. The port air distribution in the model was adjusted by global optimization to minimize the fuel requirement. The simulation results show that magnetite oxidation may be completed in the kiln with significant fuel savings.