Design of the spherical agglomerate size in crystallization by developing a two‐step bridging mechanism and the model

Abstract Spherical agglomeration technology can produce high‐performance spherical particles in a single crystallization unit, although it is still challenging to control the particle size and shape. To solve this issue, a two‐step bridging (TSB) mechanism containing a preconditioning period, size period, and shape period is proposed. The dynamic balance among the forces of adhesion, dispersion, and capillary action in the multi‐liquid phases plays a key role. This is fully considered to establish the TSB‐based thermodynamic size model and particle design framework by weighting the force action regions in multi‐liquid phases with dynamic composition. The spherical agglomerates of benzoic acid, celecoxib, and salicylic acid with narrow particle size distributions and tunable particle size ranges of 2000–5000, 800–3500, and 1500–4500 μm, respectively, were designed and prepared successfully, showing good correlation with the calculation, which is superior to the reported methods and indicates that the mechanism has certain universality and guiding significance.