Apparatus for and Method of Preparing Titanium Dioxide Sol and Paste Composition Using the Same

A method of preparing a titanium dioxide (TiO2) sol, comprising the steps of:

• (a) preparing an organic solvent mixture containing a dispersing stabilizer by mixing 1 to 30 parts by weight dispersing stabilizer and 70 to 99 parts by weight organic solvent;
• (b) preparing an organic solvent mixture containing an aqueous titanium dioxide sol and the dispersing stabilizer by mixing the organic solvent mixture containing the dispersing stabilizer of step (a) with the aqueous titanium dioxide sol in a volume ratio of 1:1 to 1:9;
• (c) replacing water with an organic solvent by separating the organic solvent mixture containing the aqueous titanium dioxide sol and the dispersing stabilizer of step (b) into titanium dioxide particles and an organic solvent mixture containing water and the dispersing stabilizer using a separation unit;
• (d) circulating the separated titanium dioxide particles obtained in step (c) and mixing the separated titanium dioxide particles with the mixture of step (b);
• and
• (e) repetitively allowing the organic solvent mixture prepared in step (b) to sequentially undergo steps (c) and (d) until the organic solvent has a purity degree of 95% or higher.