| 摘要 |
PROBLEM TO BE SOLVED: To provide a titanium oxide-coated fine hollow glass sphere having a high strength, an excellent whiteness degree, and a good photocatalytic function, by expanding a volcanic vitreous deposit as a raw material and at the same time, denaturing coated titanium oxide hydrate to titanium oxide during a heat treatment, and controlling the crystal size to 10 nm or less. SOLUTION: After a volcanic vitreous deposit powder is dispersed in an aqueous acid solution containing titanium ions and aluminum ions so that the concentration of the powder is 5-40 mass%, an aqueous solution of hydrogen carbonate is added to the suspension to deposit titanium oxide hydrate and aluminum oxide hydrate on the powder surface. Subsequently, the powder is taken out to be washed and dried, and then heat-treated at 900-1100 deg.C. |
