The tumbling agglomeration involves both disintegration of
weaker bonds and re-agglomeration by abrasion transfer and coalescence
of larger units. Coalescence occurs at contact points
and additional growth of the agglomerate may proceed by further
coalescence, or by layering, or both. The particles to be agglomerated are larger; however, the particle-to-particle adhesion needs to be increased by the addition of binders, such as
water or other more viscous liquids, depending on the properties
of the particles being agglomerated and the required strength of the agglomerate structure (
In food industries, most units use static and vibrating fluidized
beds to mix the powder, promote inter-particle collisions
and dry the granules (Coucoulas, 1992). Granules are formed by
shear processing in planetary mixers, ribbon blenders, Z-blade
units, and high-speed intensive mixers. For example, granulated
enzyme products can be manufactured by mixing enzyme solution
with a suitable filler to form dough, which is then pressed
into fine granules. The granules are then sprayed with a suitable
binder and further dried in a fluidized bed dryer (Harkonen
et al., 1993). Sometimes, a large amount of fine products are
reprocessed, causing economical burden to this technology.