Agency of Industrial Science and Technology

Dae-Yong Shin

Kunio Kimura

Disclosed is a method for the preparation of fine hollow glass spheres coated with titanium dioxide from particles of a volcanic vitreous deposit sand occurring in nature. The method comprises the steps of: (a) dispersing the starting particles in an aqueous medium containing hydrogen chloride (or sulfuric acid) and titanium chloride (or titanium sulfate); (b) admixing the aqueous dispersion of the particles with an aqueous alkaline solution such as a solution of ammonium hydrogencarbonate to effect hydrolysis of the titanium chloride (or sulfate) into hydrous titanium oxide forming a coating layer on the particles; and (c) subjecting the particles coated with hydrous titanium oxide to a heat treatment for expansion of the vitreous particles into hollow glass spheres with simultaneous conversion of the hydrous titanium oxide into titanium dioxide forming a coating layer on the hollow glass spheres.

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Kangwon-Do, South Korea

Dae-Yong Shin