Experiments were carried out to study the dynamic and kinetic behaviour during the agglomerative precipitation of CaCO3 in an MSMPR crystallizer. The results demonstrate that for certain conditions steady state can be achieved earlier for such a process than for simple crystallization. Bimodality of the PSD was once more confirmed. Kinetic constants for nucleation, growth, aggregation and disruption were estimated by non-linear least squares fitted to a discretized MSMPR population balance model. Preliminary results indicate a dependence of both crystal aggregation and agglomerate disruption on crystal growth rate, but to reverse extents.