High shear granulation: an investigation into the granule consolidation mechanism

The mechanisms of early granule growth are difficult to study and poorly understood. Consolidation and layering play a critical role in the growth process. However, little is known about the kinetics.

In this work, a novel consolidation-only granulator (COG) was used to study dynamic consolidation and layering only, eliminating other granulation mechanisms. Prenucleated granule growth was studied over time. Based on experimental data and literature models, a mechanistic layering kernel for population balance modelling was developed.

Granule growth kinetics were qualitatively predicted by a previously reported model; growth behaviour was linear with the square root of time to a certain critical size, after which growth stopped. X-ray computed tomography revealed that consolidation mainly occurred in the outer layers of the granules.

The results greatly advance understanding of consolidation and layered growth, and the new model opens the way for improved predictive modelling and design of granulation processes and products.