A Review on Spherical Crystallization Mechanisms and Characterization

Abstract

Spherical crystallization is a novel agglomeration technique that can transform crystals directly into a spherical form during the crystallization process itself. In the spherical crystallization process, crystal formation, growth and agglomeration occur simultaneously within the same system. In this method, a third solvent called the bridging liquid is added in a smaller amount to purposely induce and promote the formation of agglomerates. Spherical agglomerates can be manufactured by four techniques, namely, spherical agglomeration, quasi emulsion solvent diffusion, ammonia diffusion and neutralization method. Spherical crystallization is influenced by solvent system, solubility, feeding rate, agitation, residence time, temperature and initial size of the crystals formed. Characterization includes mainly particle size distribution, morphology, porosity and mechanical properties such as compressibility, tensile strength, mechanical strength and elasticity. The spherical agglomerates prepared using spherical agglomeration possesses good physico-mechanical properties like spherical shape, mechanical strength, compressibility and low elastic recovery.