Morphology Control in Preparing CaCO_3 Ultrafine Particles

The carbonation of lime suspension were measured in situ by using conductivity gauge and pH meter. The results showed that the carbonation rate was controlled by the absorption of CO_2 at the initial period, which was the most important stage in the overall process. Finally, it turned to be controlled by dissolution of Ca(OH)_2. TEM and X-ray diffraction were used to observe the nucleation and growth of CaCO_3 ultrafine particles. The effects of additives were discussed. It was concluded that the additive enhanced nucleation and prevented the agglomeration and grow of CaCO_3 particle. Ultrafine CaCO_3 products with different morphology were synthesized successfully.