| 摘要 |
This invention concerns a post-treatment of TiO2 having pigmentary morphological and granulometric characteristics, with the purpose of conferring to it a compact, uniform and adhering coating with a controllable specific surface area. The process comprises three stages: firstly, activating the surface of the TiO2 particles in a moving bed by treatment with an anhydrous gas at a temperature from 400 DEG to 600 DEG , secondly, reacting the particles in a moving bed with one or more chlorides selected from AlCl3, SiCl4 and ZrCl4, in the presence of a carrier gas, at a temperature from 400 DEG to 700 DEG C, and thirdly, treating the particles with a gas containing water vapour at a temperature from 200 DEG to 400 DEG C. During the second stage, the chlorides may be allowed to react with oxygen with the consequential deposition on the particles of the corresponding oxides. |
