| 摘要 |
PURPOSE:To form the titled fine hollow spherical body which is homogeneous and having high strength by coating the surface of an inorg. granulated material having mean particle diameter in the specified range with carbon powder having specified particle diameter in specified thickness. CONSTITUTION:The fine powder of an inorg. substance having <=200mu mean particle diameter is granulated to form a granulated material having from several tens of mu to several mm mean particle diameter. The surface of the granulated material is coated with carbon powder having <=10mu mean particle diameter in 300-12,000mmu thickness. Then the granulated material coated with the carbon powder is rapidly heated to a temp. 100 deg.C higher than the m.p. of the inorg. substance and to <=3,500 deg.C, and kept at the temp. for <=5min. Consequently, a hollow molten droplet of the inorg. substance which is hollow on the inside and coated with the carbon powder layer on the outside is formed. The droplet is rapidly cooled before the hollow molten droplet becomes a solid- core molten droplet, and the outer shell of the hollow molten droplet is solidified to obtain the fine hollow spherical body. |
