| 摘要 |
A hot gaseous suspension of TiO2 produced by vapour phase oxidation of TiCl4 is quenched directly with water to form a slurry of TiO2 and to dissolve unreacted TiCl4. The suspension may be at 300-1000 DEG C. and may contain 0.5-5% TiCl4 by weight of TiO2. The water may be at 20-75 DEG C. and may comprise recycled TiO2 slurry. The process may be operated continuously, semi-continuously, or batch-wise, under atmospheric or super- or sub-atmospheric pressure. The resultant gas stream containing Cl2, O2 and H2O vapour may be passed through a condenser, where water is recovered and recycled, and then passed to chlorinating apparatus. The product slurry may have, or be adjusted to have, a pH of less than 4. It contains Ti hydroxide and hydroxy chlorides resulting from hydrolysis of the dissolved TiCl4, which are said to enhance the pigmentary properties. If scouring agents, e.g. sand or alumina or TiO2 aggregates, were present on the suspension, they settle on the slurry and can be removed. |
