Agglomeration in suspension of salicylic acid fine particles: influence of some process parameters on kinetics and agglomerate final size

Agglomeration in suspension is a size-enlargement method that facilitates operations of solid processing (filtration, transport, galenic) and preserves the solubilization properties of fine particles. It consists in adding to a suspension of microparticles a small quantity of a second liquid acting as an interparticle binder; in a suitably agitated equipment with a critical quantity of binder, spherical and dense agglomerates of a few millimeters in diameter may be formed. This paper presents a new methodology to study the agglomeration process. The system [salicylic acid/aqueous solution/chloroform] is chosen as a model system. To follow in situ the agglomerate formation and growth, an original device based on image acquisition and analysis is developed; agglomerate porosity and compressive strength are also measured. These measurements allow us to identify the influence of the process parameters on the agglomeration kinetics, the size and the compressive strength of the final agglomerates. They also give interesting insights into the mechanisms.