Revealing Crystal Aggregates’ Evolution through In Situ Visualization in Cooling Crystallization

The transition process and control mechanisms of crystal aggregates to agglomerates hold significant importance in reducing subsequent processing steps and enhancing crystal purity. This study used the cooling crystallization of potassium chloride as a model system to conduct real-time data collection using high-speed visualization methods, which allows a detailed analysis of the transition process in aggregate size and morphology. When the cooling time increases, the snowflake-like aggregates expand rapidly and then undergo uneven breakage, resulting in smaller aggregates. As aggregates gradually transform into agglomerates, a special rise in the Sauter mean diameter is observed, followed by a gradual decrease. These findings offer practical data for future model establishment and simulation validation and enhance our understanding of the evolution mechanisms of aggregates.