ACIDIC ACTIVATED ALUMINA AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain the acidic activated alumina having pH on the acidic side and having adsorptivity to the metallic components and other basic components in addition to the adsorptivity of activated alumina by mixing aluminum hydroxide and ammonium chloride and/or ammonium sulfate and calcining the mixture. SOLUTION: At least one aluminum hydroxide among gibbsite-structure aluminum hydroxide, pseudoboehmite-structure aluminum hydroxide and bayerite- structure aluminum hydroxide is mixed with 0.5-3.0 wt.% ammonium chloride and/or ammonium sulfate on a 150 deg.C dry basis, and the mixture is calcined at 450-700 deg.C. The product contains >=97 wt.% Al2O3 when measured on a 150 deg.C dry basis and has 150-400 m2/g BET specific surface and 0.2-0.7 cc/g pore volume. The pH of its 2 wt.% aq. suspension of the acidic activated alumina is valued at 4.0-7.0. The product having 5-100μm median diameter on a volume basis is preferable.