Agglomeration behavior of anhydrous L-ornithine-L-aspatate crystals during semi-batch drowning-out crystallization

Crystallization of L-ornithine-L-aspartate (LOLA) by drowning out was carried out to produce the anhydrous form of agglomerates. The primary crystal size in the agglomerate remained unchanged after completion of the crystallization. The LOLA aqueous solution introduced into the system was immediately dispersed and cluster coagulated on the surface of the crystals. On the surface of the crystals, a cluster reached critical nuclei size, nucleated and intergrowth to form agglomerates. It was proposed that a spherical agglomeration occurred during secondary nucleation by coagulation model and intergrowth. The agglomerates size and size distribution were varied with the process parameters. The agglomerate sizes of LOLA crystals appeared to be ruled not only by secondary nucleation rate but also by the mass of suspended agglomerates. Moreover, the agglomeration rates of fine particles were higher than the agglomeration rates of large agglomerates. Using these properties, the uniform agglomerates size distribution could be obtained.