Patent ID: 6387339
Filing Date: 2002-05-14
Classification: C01F,C01P

Abstract:
A method for the preparation of particles of a rare earth oxide, comprising the steps of:mixing an aqueous solution of a water-soluble salt of a rare earth element and an aqueous solution of oxalic acid at a temperature not higher than 15Â° C. to form precipitates of a rare earth oxalate in an aqueous medium; filtering and washing the precipitates of the rare earth oxalate with water at a temperature not higher than 15Â° C. to form wet precipitates; freezing the wet precipitates of the rare earth oxalate at a temperature not higher than âˆ’25Â° C. to form frozen precipitates; drying the frozen precipitates of the rare earth oxalate by vacuum drying to an extent that the content of water therein including the washing water and water of crystallization does not exceed 20% by weight relative to an anhydrous form of the rare earth oxalate, to form dried precipitates; and calcining the dried precipitates of the rare earth oxalate in an oxidizing atmosphere, to form particles of the rare earth oxide.