| 摘要 |
PURPOSE: To produce a sol having excellent stability and superior transparency in an alkali region by allowing an acidic hydrated alumina sol to contact with an anion exchanger in the presence of an alkali in an aqueous phase. CONSTITUTION: In this production, 1×10<-3> to 0.1mol of an alkali per mol of alumina (Al2 O3 ) is added to an acidic hydrated alumina sol which consists of a single kind or plural kinds of crystals having fibrous, spherical, chainlike, platelike or undefined form and a 1 to 500nm average grain size and also has a 1 to 20wt.% alumina concn., to adjust the pH of the resultant liquid suspension to 8 to 11. Then, this liquid suspension is allowed to contact with 1 to 20liter of an anion exchanger such as strongly basic or weakly basic anion exchange resin per kg of alumina (Al2 O3 ) at room temp. to 100 deg.C for 0.5 to 50hr to obtain the objective alkaline hydrated alumina sol having absorbances of <=1.0, <=1.5 and <=2.5 at 800, 560 and 400nm wavelengths, respectively, when the alumina concn. of the sol is 0.5wt.%. This sol can be used not only for producing a catalyst carrier but also in a wide variety of application fields.
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