A novel generally applicable multi-component and multi-phase population balance model is presented. The model classifies precipitation and crystallization systems into the number of components (i.e. building units of solid) and number of solid phases. The model includes reaction equilibria of metal ions in aqueous media, activity modeling, mixing, particle formation kinetics, population and mole balances. The new model is applied to the initial stages of copper catalyst precursor formation. The population balance model is simplified to a single-solid phase and multi-component precipitation. Simulations for several solid phases were performed at various experimental conditions. We show that the formation of the carbonate rich Georgeite phase is favored. The simulation results are verified by the measured global parameters pH and solid weight. Mixing plays a minor role in comparison to the variation of the reactant concentration. The timescale of precipitation including mixing, nucleation and crystal growth ranges from microseconds up to 1 s depending on the extent of secondary nucleation. (C) 2014 Elsevier Ltd. All rights reserved.