| 摘要 |
PURPOSE:To efficiently produce a lamellar alumina particle suitable for a pigment for coating material or a raw material for ceramics. CONSTITUTION:This producing method is one by containing or adding a crystal control agent (NaOH, Na2SiO3 or the like) into a aluminum hydroxide or alumina hydrate adjusted in particle size and hydrothermal synthesis treating (at >=350 deg.C, <=200atm). And each of the contained or added quantity of NaOH and Na2SiO3 is adequately 5.4X10<-3>-0.022mol and 2.25X10-3-0.090mol per 1mol Al(OH)3 respectively. As a result, the lamellar alumina particle uniform in particle diameter and large in aspect ratio is obtained and the particle has excellent effect for applications such as the pigment for coating material, for ceramics molding and for an abrasive material. And the lamellar alumina particle is obtained even by using a low purity raw material. |
