| 摘要 |
PROBLEM TO BE SOLVED: To provide a method in which high purity silica can be produced simply at low cost. SOLUTION: The method for producing high purity silica includes: (A) an alkali dissolution step of mixing a silica-containing mineral powder with an alkaline aqueous solution to form an alkaline slurry having a pH of 11.5 or more to allow Si, Al, and Fe in the silica-containing mineral powder to be dissolved in a liquid, followed by subjecting the alkaline slurry to solid-liquid separation to obtain a liquid containing Si, Al, and Fe; (B) a Si liquid separation step of mixing the liquid obtained in the step (A) with an acid to bring the pH to 10.3 or more and less than 11.5 to precipitate Al and Fe in the liquid, followed by performing solid-liquid separation to obtain a liquid containing Si; and (C) a silica separation step of mixing the liquid obtained in the step (B) with an acid to bring the pH to 9.0 or more and less than 10.3 to precipitate Si in the liquid, followed by performing solid-liquid separation to obtain a solid containing SiO<SB>2</SB>. COPYRIGHT: (C)2011,JPO&INPIT
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