| 摘要 |
PURPOSE:To produce alumina powder having improved dispersibility and stability with time, by X-ray diffractometrically subjecting amorphous hydrated alumina to hydrothermal treatment, adding and mixing a diol and amorphous hydrated alumina to the treated hydrated alumina and aging the resultant mixture while heating. CONSTITUTION:An X-ray diffractometrically amorphous hydrated alumina is subjected to hydrothermal treatment at about 100-300 deg.C for about >=0.1hr by a well-known method to give alumina having boehmite structure. A diol, e.g. ethylene glycol, or triol, e.g. glycerol, and amorphous hydrated alumina are added, mixed with the resultant alumina and aged while heating at about 70-100 deg.C for about >=0.5hr. The amount of the diol or triol to be used is about >=0.01mol based on 1mol Al2O3 and the amount of the amorphous hydrated alumina to be used is about 0.02-0.5mol expressed in terms of Al2O3. The thermally aged alumina is heat-treated at about >=100 deg.C to afford the aimed alumina powder having remarkably improved dispersibility and stability with time.
|
