| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for simply producing high purity silica at a low cost. <P>SOLUTION: The method for producing high purity silica includes: (A) a step wherein a silica-containing mineral powder is mixed with an aqueous alkali solution so as to adjust a pH to ≥11.5, Si is dissolved so as to achieve an Si concentration in the liquid component of ≥3.0 mass%, and solid-liquid separation is carried out; (B) a step wherein the resulting liquid component is mixed with an acid so as to adjust the pH to <3.0 and solid-liquid separation is carried out; (C) a step wherein the resulting liquid component is mixed with an alkali source to prepare an aqueous solution whose pH is <4.0 and/or the liquid component is heated to 40-100°C and solid-liquid separation is carried out; (D) a step wherein between the steps (A) and (B) and/or between the steps (B) and (C), the liquid component obtained in the former step is subjected to ion exchange treatment and/or activated carbon treatment; and (E) a step wherein a solid component obtained in the step (C) is mixed with an acid solution so as to adjust the pH to <3.0 and solid-liquid separation is carried out to obtain a solid component containing SiO<SB POS="POST">2</SB>and a liquid component containing impurities. <P>COPYRIGHT: (C)2012,JPO&INPIT |
