Granulation or size-enlargement is any processes whereby small particles are gathered into larger relatively permanent masses in which the original particles can still be distinguished. There are lots of advantages of granulating particles, for example, improving their flowability, cohesiveness, and bioavailability; controlling the release or interaction of these particles into or with the surrounding medium or environment; preventing dust explosions or inhalation of toxic or allergenic materials.

Many techniques are known for preparing granulations from powdered materials such as wet granulation, solvent granulation and melt granulation. Wet granulation and solvent granulation require the addition of a liquid binder which aggregates the active materials, carriers and other ingredients into granules. After granulation, the liquid generally must be removed by a separate drying step. Melt granulation is similar to wet granulation, but uses a low melting point solid material as a binder. The solid binder in melt granulation is melted and acts as a liquid binder thereby aggregating the powdered active material and other ingredients into granules. Binder thereby, is permanently incorporated into the granules when the granules cool.

Each of these granulation techniques has certain limitations or disadvantages. Wet granulation requires a liquid to be added, and the liquid must subsequently be removed. Therefore, a drying step is needed which further complicates the manufacturing process and risks more contamination. Additionally, wet granulation is not well suited to making granules which incorporate water absorbing disintegrants. It is most likely that the disintegrants will adsorb the water to produce a swollen mass instead of discreet granules. To solve this problem and avoid the inactivation of water sensitive actives, a solvent based granulation can be used. The solvent used in this granulation process is generally a volatile hydrocarbon or alcohol which can easily be removed from the granules after they are formed. However, the use of highly volatile solvents present a new set of problems. For example, these solvents are generally environmentally deleterious and have a great risk of explosion during handling them. Furthermore, governmental regulation has a strict limitation of the solvent residue in some granule products, such as in pharmaceuticals and food products. Melt granulation on the other hand avoids the problems associated with adding liquids by incorporating a low melting solid binder. However, the low melting point binder must be heated to at least its softening point and melted during the granulation process, which will strictly limit the number of active materials which can be granulated.

This paper presents a new method for granulation of fine particles, which overcomes some limitations that conventional granulation methods have, and also being capable of handling especially thermally sensitive materials. The granules produced by this new process are suitable for agriculture, pharmaceutical, and food uses.