The way of conducting the precipitation process is crucial for the final product properties and its further applications. In the presented experiments, CaCO3 powders were produced by controlled fast precipitation through gaseous CO2 absorption in Ca(OH)(2) slurry. This multiphase reaction was conducted in a new rotating disc reactor unit, which enables one to control inter- and intra-face mass and energy transfer as well as the macro- and micro-mixing effects in the reacting system. The effect of calcium hydroxide concentration, mixing conditions in the reactor and gas-liquid interface development at discs surface on precipitated CaCO3 was investigated. The analysis with the dynamic light scattering method (DLS) showed that mean particle diameter decreases with higher rate of discs revolution speed and higher calcium hydroxide concentration. The Xray diffraction testing revealed that we have obtained a chemically pure calcite, which is the most stable polymorph of CaCO3. The scanning electron micrographs (SEM) showed the influence of precipitation conditions on rhombohedral calcite crystals. Sorptometric surface analyses reveal high development of specific surface area (over 20 m(2)g(-1)) and powders porosity. (C) 2009 Elsevier B.V. All rights reserved.