| 摘要 |
PURPOSE: To produce superfine nonacicular α-ferric oxide particles each made of a single crystal, having a narrow particle size distribution, minimizing flocculation energy because of the most stable surface state as particles and remarkably excellent in dispersibility. CONSTITUTION: An aq. ferric salt soln. and an aq. alkali soln. are simultaneously neutralized at 5-70 deg.C and the resultant ferric hydroxide is separated by filtration, washed with water and dispersed in water to prepare a slurry of pH6-10. This slurry is brought into a hydrothermal reaction at 130-200 deg.C to obtain the objective nonacicular α-ferric oxide particles each made of a single crystal and having 0.01-0.1μm average particle diameter. |
