Preparation of CaCO₃-TiO₂ Composite Particles and Their Pigment Properties.

CaCO₃-TiO₂ composite particles were prepared with calcium carbonate (CaCO₃) and TiO₂ in stirred mill according the wet grinding method. The pigment properties, morphology, and structure of CaCO₃-TiO₂ composite particles and the interaction behaviors between CaCO₃ and TiO₂ particles were explored. In the CaCO₃-TiO₂ composite particles, TiO₂ is uniformly coated on the surface of CaCO₃ and the firm combination between CaCO₃ and TiO₂ particles is induced by the dehydration reaction of surface hydroxyl groups. CaCO₃-TiO₂ composite particles have similar pigment properties to pure TiO₂. The hiding power, oil absorption, whiteness and ultraviolet light absorption of composite particles are close to those of pure TiO₂. The application performance of CaCO₃-TiO₂ composite particles in the paint is consonant with their pigment properties. The contrast ratio of the exterior paint containing CaCO₃-TiO₂ composite particles is equivalent to that of the paint containing the same proportion of pure TiO₂.