In the iron-ore pellet induration process, the green ball packing influences the porosity, the permeability, and the
surface area of pellet bed. Take the plastic deformation and size distribution of green balls into consideration, an improved
numerical model for sphere packing process is presented by using dropping and rolling rules which are derived from a realistic
physical phenomenon. The simulation is taken for different packing heights and size distributions, and the corresponding
accurate porosity, permeability and surface area for normal distribution of sphere radii can be got. The simulation result
shows that the model is efficient and well reflects realistic packing process, and it also provide the foundation of accurate
drying and induration model.