Process for synthesis of uniform colloidal particles of rare earth oxides

Abstract

An improved process for the preparation of monodispersed spherical colloidal particles from rare earth salts is disclosed. These colloidal particles are obtained in this process by homogeneous precipitation techniques involving the forced hydrolysis of rare earth salts in aqueous media. More specifically, this process initially involves the formation of hydrolyzed cations which are precursors or intermediate to precipitation of the desired colloidal particle. The objective in the formation of this precursor species is to reach critical supersaturation concentration of this particle forming species so that only one burst of nuclei occurs. Colloidal particle formation is then effected by diffusion of solutes onto the existing nuclei. The improvements of this process reside, in part, in the ability to control the kinetics of formation of this intermediate species. Such control permits the formation of colloidal dispersions having very narrow particle size distribution. The colloidal dispersions of these particles are also quite stable. The rare earth colloidal particles prepared by this process are useful in both industrial and biologic environments.