| 摘要 |
PURPOSE:To acidic aqueous solution containing Ce and other rare earth elements is divided into 2 fractions, one fraction is combined with an alkali and the formed solid and an oxidizing agent are added to the other fraction whereby the titled compound is readily obtained through a simple process with industrial advantage. CONSTITUTION:An acidic aqueous solution containing Ce and other rare earth elements such as La, Pr, Nd is divided into 2 fractions and one fraction 1 is combined with an alkali hydroxide such as sodium hydroxide or ammonia to form a solid. At this time, an oxidizing agent such as air is preferably added thereto. The formed solid is rare earth metal hydroxides and th addition of an oxidizing agent makes Ce tetravalent Ce(OH)4. The solid is separated and admixed together with an oxidizing agent such as hydrogen peroxide to the other fraction 2. The mixing is preferably effected at 40 deg.C to room temperature. The mixture is preferably stirred at 60-80 deg.C for additional 2-6hr. All Ce is converted into Ce(OH)4 and the other rare earth hydroxides dissolve in water. The mixture is filtered to give Ce(OH)4 of high purity.
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