CONTINUOUS SYNTHESIS OF TITANIUM-DIOXIDE FINE PARTICLES USING A SLUG FLOW AGING TUBE REACTOR

A continuous reactor system for titanium dioxide fine particle synthes is has been proposed, in which a packed bed for the nucleation of fine particles was connected in series with a slug flow ageing tube for gr owth of the particles. By injection of nitrogen gas into the inlet of the ageing tube, the continuous liquid feed was separated into small p ortions so that slug flow was formed. Spherical unagglomerated fine pa rticles of titanium dioxide were obtained using this reactor system, a nd the effectiveness of using slug flow was elucidated. The effects of some operation variables such as liquid flow rate in the ageing tube and tube diameter were also examined. The particles obtained under the slug flow condition had narrower particle size distribution than thos e under a laminar flow condition at any flow rate. Particle geometric standard derivation (GSD) was found to be as small as that obtained in a batch process. No quality difference in particle GSD exists between ageing tubes of 2 mm i.d. and 3 mm i.d. for the slug flow. Chronomal analysis assuming diffusion-controlled growth was applied and was foun d to be effective for simulating a continuous particle synthesis proce ss of titanium dioxide.