In this paper, production of precipitated calcium carbonate (PCC) with required particle size and morphological structure, along with its dependence on technological parameters and the 'properties of. Ca(OH)(2), is discussed. The effect of the reaction environment on the kinetics of CaO hydration and the formation of crystals in water suspension was established. A remarkable difference in the system's, restoration ability after stirring was observed. The hydration process is initially controlled by a kinetic mechanism, followed by a diffusion-controlled process. The dissolution speed of lime hydrated to suspension is eight times higher than that of lime hydrated to powder. Particles of hydrated lime appeared in various forms.