PROBLEM TO BE SOLVED: To provide a method for producing silica-based particles, having substantially no cavity in the interior portion of the particle, wherein the interior portion is porous or nonporous (not porous), or silica-based particles having an outer shell and having a cavity inside the outer shell, wherein the outer shell is porous or nonporous, and silica-based fine particles having an outer shell and having a cavity inside the outer shell, wherein the outer shell is porous or nonporous and the interior portion is kept under negative pressure.SOLUTION: The method comprises: (a) a step of preparing silica-based particle precursor particles by spray-drying an alkali silicate aqueous solution in a hot air flow (b) a step of immersing the silica-based particle precursor particles in an acid aqueous solution to remove the alkali and (c) a step of drying and heat-treating the resulting particles.COPYRIGHT: (C)2012,JPO&INPIT【課題】粒子内部に実質的に空洞がなく、内部が多孔質または非孔質(無孔質)であるシリカ系粒子、あるいは外殻を有し、外殻内部に空洞を有し、外殻が多孔質または非孔質であるシリカ系粒子、さらに、外殻を有し、外殻内部に空洞を有し、外殻が多孔質または非孔質であり、内部が負圧であるシリカ系微粒子の製造方法の提供。【解決手段】(a)珪酸アルカリ水溶液を熱風気流中に噴霧乾燥してシリカ系粒子前駆体粒子を調製する工程、(b)シリカ系粒子前駆体粒子を酸水溶液に浸漬し、アルカリを除去する工程、および(c)乾燥・加熱処理する工程、よりなる。【選択図】なし
