| 摘要 |
PURPOSE:To manufacture ultrafine granular zirconia of high purity by dissociating thermally zircon to zirconia and silica and thereafter applying a chlorination process to the mixture. CONSTITUTION:Zircon is thermally dissociated to zirconia and silica at a high temp. making use of a plasma furnace for example. Next, the thermally dissociated zircon is blended with carbon powder to make a mixture and the mixture is caused to react with chlorine at 400-600 deg.C. As a result, gaseous product of ZrCl4 and SiCl4 is obtained. When the mixed gaseous product is introduced into water, ZrCl4 and SiCl4 are hydrolyzed immediately and ZrCl4 is converted into ZrOCl2 and also SiCl4 is precipitated as SiO2 and simultaneously TiCl4 contained as an impurity is precipitated as H4TiO4. When these precipitates are removed by filtration and thereafter the filtrate is made acidic with hydrochloric acid, ZrOCl2 is precipitated as basic zirconium hydrochloride and the chlorides of Al, Fe remain in the filtrate. After filtering the mixture, the precipitate is sintered to obtain ultrafine granular zirconia having high purity. |
