Patent ID: 6884406

Claim:
A process for preparing an alumina composition, consisting essentially of: adding water and one of a monobasic acid or its salt to at least one aluminum hydroxide and/or alumina selected from the group consisting of substances (A) to (D): (A) acid-containing aluminum hydroxide obtained by heating aluminum hydroxide in the presence of one of a monobasic acid or its salt; (B) acid-containing alumina obtained by treating ρ-alumina or γ-alumina in the presence of one of a monobasic acid or its salt; (C) bayerite; and (D) γ-alumina, to prepare a reaction mixture having a k value adjusted to be in the following range, said k value being represented by the following formula: 0.0001≦k≦0.20 k =( b/a )×( b/c ) wherein a is a number of moles of alumina in the reaction mixture in terms of Al 2 O 3 , b is a number of moles of the acid or its salt, and c is a number of moles of water, and optionally adding a pore structure controlling agent selected from the group consisting of an oxygen-containing organic compound and inorganic polybasic acid, then subjecting the reaction mixture to sol-forming reaction at a temperature of not higher than 250° C. to obtain one or both of an aqueous alumina sol and an aqueous alumina gel, optionally subjecting one or both of the aqueous alumina sol and the aqueous alumina gel to neutralization with an alkali and hydrothermal treatment at a temperature of not higher than 250° C.; and subjecting one or both of the aqueous alumina sol and the aqueous alumina gel to molding, then drying and calcining.