A multi-component mass transfer rate based model for simulation of non-equilibrium crystal growth

Abstract To overcome the short-coming in the previous tools on the simulation of composition of crystals during growth, we proposed a model based on multi-component mass transfer for modelling the growth behavior of crystals. The core of the model is a phase non-equilibrium model of a single crystal that treats the solute components equally and describes them by a set of mass transfer equations. The size, shape and composition of a crystal at a given time during the crystallization process, i.e. the size in each face direction and the area of each face, depend on the amount of each material deposited on each surface. This is unlike conventional facet growth kinetic model in which the growth rate is correlated directly to supersaturation. Such models can be applied to describe co-crystallization processes, estimate the impurity content in product and enables the prediction of stability of crystalline pharmaceuticals. The modelling method is illustrated by reference to a detailed case study of NaNO 3 crystal growth in water in the presence of KNO 3 . The dynamic evolution of crystal composition, shape, and size is predicted in simulation runs under different initial KNO 3 concentrations.