Physical Simulation of Molten Slag Granulation by Rotary Disk

A physical model of molten slag granulation by rotary disk was developed based on the mechanism of Newtonian liquid granulation. For geometrical similarity, the radius ratio of model disk to the prototype disk was chosen as 1 : 1. For dynamic similarity, equality of Ohnesorge number between the model and the prototype was achieved firstly by compounding rosin and paraffin wax with mass ratio of 1 : 1 as simulation liquid of molten blast furnace (BF) slag, and the simulation material can satisfy the similarity of liquid-solid transformation during falling in the medium; then equality of Reynolds number and Weber number was obtained by controlling the volumetric flow rate and the rotary speed, respectively. Model accuracy was verified by comparing the simulation data with the results reported in literature, which showed good agreement with the calculation results of empirical equation and the actual molten BF slag granulation from the view point of particle size. Furthermore, influences of disk radius, rotary speed and liquid flow rate on granulation were discussed using the developed model, and the Kitamura equation was modified according to the simulation data which can predict particle size more accurately. Using the modified equation, the operation parameters were predicted according to the flow rate of molten industrial BF slag.