Nucleation and Growth Kinetics of Potassium Dihydrogen Phosphate Crystal in Stirred Tank Crystallizer

The use of stirred tank crystallizers (STCs) for the separation and purification of crystals has recently garnered increased attention. Previous research on the crystallization of potassium dihydrogen phosphate (KDP) has primarily concentrated on process efficiency and thermodynamics, with less emphasis on kinetics. In this study, we employ STC technology to delve into the crystallization process of KDP. We explored the mechanisms underlying crystal formation by continuously withdrawing a suspension containing target crystals of a specific size distribution. Our investigation of the KDP crystallization process focuses on key parameters-suspension density (M-T), solution supersaturation (Delta C), and stirring rate (N-P) that influence crystal growth and the nucleation process. We propose and validate two crystallization kinetic models for crystal growth and nucleation rates against STC data. By employing multivariate nonlinear regression analysis, we extract crystallization kinetics parameters using the crystallization kinetics model. We also conduct comparative studies of two crystallization kinetic rates. Our findings reveal that the parameters provided by the kinetic mathematical model align well with the experimental data. Furthermore, the discrepancy between experimental and calculated values is maintained within an acceptable range.