1989 Volume 29 Issue 9 Pages 761-770
A mathematical model for particle size distribution in bell-type charging at blast furnace top was developed, which is capable of estimating the radial average size distribution as well as the radial deposit distribution of each particle size for multiple size burden with a few fixed parameters.
The following findings were considered in the construction of the model. The radial deposit distribution of particles in blast furnace was determined by both the sieving process and the deposit process on the slope. The elemental process in the sieving process is the percolation of small particles through voids between large particles acting as sieves. Principal factors affecting the percolation are the ratio of large particle size to small particle size and the particle velocity gradient in the flowing layer on the slope.
The validity of the model was confirmed through actual filling tests at various blast furnaces with different throat diameters and charging conditions.
The model was applied to the prediction of the change of particle size distribution caused by the decrease of large bell stroke at Wakayama #4 BF. The monitored results showed the decrease of gas flow resistance and the suppression of peripheral gas flow as were predicted by the model with help of a gas flow simulation model.
