Kinetic effects on particle morphology and size distribution during batch precipitation

Abstract

This paper reviews the effect of growth and aggregation kinetics on particle shape and size distribution of batch precipitations. Crystal growth kinetics at each crystal surface determine the final crystal shape. These processes are affected drastically by impurities. Impurities typically used to alter crystal shape fall into the following categories: anions, cations, ionic surfactants, non-ionic surfactants and chemisorbed species. These impurities absorb in different ways on specific crystal faces, changing their growth kinetics and thus altering the crystal shape. Non-ionic polymer surfactants are effective in preventing aggregation by steric stabilization. When aggregation occurs, aggregate shapes are fractal. The mean size of precipitated particles and their size distribution are also discussed in view of various kinetic growth mechanisms.