Patent ID: 6673143
Filing Date: 2004-01-06
Classification: C04B

Abstract:
An aqueous slurry of particles of a rare earth hydroxide, of which the primary particles of the rare earth hydroxide have a particle diameter not exceeding 150 nm, having an electric conductivity not exceeding 2 mS/cm at room temperature, said slurry produced by a process which comprises the steps of:(a) mixing an aqueous solution of a water-soluble rare earth compound and an aqueous solution of a basic compound to precipitate rare earth hydroxide particles in an aqueous precipitation medium; (b) collecting the rare earth hydroxide particles by separating from the aqueous precipitation medium to give a cake of the rare earth hydroxide particles; (c) repeatedly washing the cake of the rare earth hydroxide particles with deionized water until the washing has an electric conductivity not exceeding 3 mS/cm at room temperature; and (d) dispersing the rare earth hydroxide particles in deionized water as a dispersion medium to give an aqueous slurry.