COATING MASS DISTRIBUTIONS OF SEED PARTICLES IN A TUMBLING FLUIDIZED-BED COATER

In order to control the extent of particle coating, it is necessary to clarify how the amount of coating material of each individual seed pa rticle varies with operating condition. The influence of these conditi ons on the distribution of the mass of coating material, deposited on each single seed particle treated in a tumbling fluidized bed, was exp erimentally examined in this work. As a result, the coating mass per u nit surface area of a single seed particle was proven to obey a normal distribution by number. Moreover, it also became clear that the coeff icient of variation of the coating mass distribution, c(v), decreased with increasing coating time and size of the seed particle, and with d ecreasing their holdup. However, the rotational speed of the disk, whi ch forces the aggregative coated particles apart, hardly affected the c(v) value in the experiment. (C) 1998 Elsevier Science S.A. All right s reserved.