(9f) Coating and Granulation of Fine Particles in Fluidized Bed

Fluidized beds are widely used for particle coating and granulation in pharmaceutical and chemical industries due to its high heat and mass transfer efficiency, and ease of scale-up. However, the conventional fluidized bed cannot be used for handling fine particles (less than 40 microns) due to their poor fluidization. In this paper, a proprietary technique, which involves the use of nanosized particle along with the particles (less than 40 microns) to be coated, is developed for improving the fluidization behavior of cohesive powders. Utilizing this technique, experiments on coating and granulation of fine particles (15 micron cornstarch and 12 micron aluminum) are performed using the Mini Glatt Fluidized Bed. The results indicate that the fine particles can be stably fluidized after they are pre-treated with nanosized particles. Subsequently, very uniformly coated particles can be obtained through this novel approach. By changing the operating conditions, the same process can be used for granulation of fine particles. The effect of changing the operating variables on the properties of the final product is also investigated.