VERTICAL GRANULATION IN A HIGH SHEAR MIXER

Wet granulation of solids is one of the key manufacturing steps, particularly in the production of tablet formulations. In this process, small, powdery particles are combined into granules with the addition of a granulating liquid (e.g. water, PVP solution, etc.). Vertical high-shear mixers have become established in the pharmaceutical industry as a suitable granulation technology. After wet granulation, the granules are usually transferred to a fluid bed dryer for drying. 

In addition to their use in the pharmaceutical industry, vertical high shear mixers can also be used for a wide range of cosmetic and food products. They are particularly easy to access and clean.

THE GRANULATION PROCESS IN A VERTICAL HIGH SHEAR MIXER

1. Mixing:
   The powdery raw materials are brought into a vortex and intensively mixed by means of the mixing tool rotating close to the bottom of the mixing drum.
2. Mositure addition:
   A defined amount of granulation liquid (e.g. water or PVP solution) is added after the mixing process. The liquid is added into the effective area of the chopper to ensure optimum liquid distribution. 
3. Granulation:
   The individual product particles are moistened and bonded together, gradually forming granules. The dynamics of the vortex-like product movement and the shape of the mixing tools assist this process. The granule size can be calibrated by using a sieve while discharging the product from the high shear mixer.
4. Granulate dryings:
   After granulation, the granules are usually dried to remove excess moisture. This drying process usually takes place in a fluid bed dryer.