The CaCO8 hollow spheres made of fine CaCO8 particles were prepared by a novel method. The principle of this method was as follows: the CaCOs fine particles were made attached to the surface of kerosene droplets in CaCl2 aqueous solution. Then, those particles were bound with CaCO8 gradually precipitated by the reaction between Ca2+ and CO82- in the aqueous phase. The spherical shells were obtained by replacing kerosene with ethyl alcohol and then drying at 343 K. The structure of the hollow spheres have been observed through the scanning electron microscope. The powder size distribution and the specific surface area of them were measured. These results show that each sphere is 100-250 µm in size and has the spherical shell which consists of the single layer of the component particles bound with microcrystalline CaCO8. The effects of CaCl2 concentration and pH on the preparation are discussed. The efficiency of formation was dependent on the concentration of CaCl2 in aqueous phase where emulsion was formed. On the basis of electrokinetic data for the solid particles and the droplets, the interaction between them was discussed.
ASJC Scopus subject areas
- Chemical Engineering(all)