Control of calcium carbonate morphology by precipitation in compressed and supercritical carbon dioxide media

摘要

This paper reports a new method to produce calcite crystals with scalenohedral and rhombohedral morphologies in the Ca(OH)(2)-H2O-CO2 system, without the use of any tailor-made additive. Compressed CO2 vapour (25 degreesC, 50 bar), liquid CO2 (25 degreesC, 200 bar) and supercritical CO2 (45 degreesC, 200 bar) were used to precipitate CaCO3. De-aggregated calcite crystals of rhombohedral habit and narrow crystal size distribution were prepared using a novel route that consists in the reaction of an aqueous suspension of Ca(OH)(2) with compressed carbon dioxide. In the new method, morphological control, overall production rate and conversion efficiency are enhanced with respect to the established industrial carbonation process. (C) 2004 Elsevier B.V. All rights reserved.