Modelling and analysis of particle formation during agglomerative crystal precipitation processes

While nucleation and crystal growth are normally considered to be the primary particle formation processes during industrial crystallization, secondary processes including crystal agglomeration and breakage can have a determining effect on product form, especially of precipitates. In addition to the usual overall size distribution, primary and secondary particle size, particle structure and morphology then become important characteristics affecting both product quality and downstream processing performance. In this paper, the kinetics of processes which determine the formation of both primary particles and crystal agglomerates are briefly reviewed together with established and recent population balance and simulation techniques for analysing and predicting primary and secondary particle size distributions and total specific surface area. These approaches are then illustrated by some experimental and modelling studies of agglomerative precipitation reported recently in the literature.