《Preparation of calcium carbonate particles coated with titanium dioxide》.pdf

International Journal of Minerals, Metallurgy and Materials Materials Volume 16, Number 5, October 2009, Page 592 Preparation of calcium carbonate particles coated with titanium dioxide Hai Lin, Ying-bo Dong, and Le-yong Jiang School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China (Received 2008-12-23) Abstract: The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was stud- ied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanochemi- cal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5:3.5. The mass ratios of two different types of titanium dioxide (anatase to rutile) and grinding media to grinded materials were 8:2 and 4:1 respec- tively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification. The hiding power and oil absorption of this new material were 29.12 g/m2 and 23.30%, respectively. The results show that the modi- fication is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be im- proved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide. Key words: calcium carbonate; mechano-chemical process; titanium dioxide film; hydroxylation 1. Introduction CaCO3 before and after modification were tested re- spectively. The study aims to use cheap CaCO3 in- Titanium dioxide (TiO ) is of relevance to a num- 2