Investigations on ultra-fine grinding of titanium dioxide in a stirred media mill

This paper is focused on the grinding and dispersion of TiO2 in a stirred bead mill. Batch and continuous wet grinding experiments have been carried out and the best conditions for grinding TiO2 have been identified with respect to agitation speed, suspension flow rate, media size and filling volume. Kinetics equations, based on the linear combination of log-beta laws describing the changes of multimodal size distributions vs. grinding time have been established. A process model for continuous comminution of TiO2 has been derived. The transport of the fragmented particles was modelled by four agitated cells with backmixing. Combining this model with grinding kinetics, the product size distribution achieved by continuous grinding was calculated and compared to experimental results.