Patent ID: 7799303
Filing Date: 2010-09-21
Classification: C01B,Y10S

Abstract:
1. A method of preparing silica nanoparticles from siliceous mudstone, comprising: heat-treating siliceous mudstone to remove water; leaching the sliceous mudstone with hydrochloric acid to remove impurities, thereby forming a silica constituent; leaching the silica constituent with sodium hydroxide, thereby forming a sodium silicate aqueous solution; passing the sodium silicate aqueous solution over an ion-exchange resin at a linear velocity of 2.0 to 0.5 cm/sec to remove a sodium constituent from the sodium silicate aqueous solution, thereby producing a silicate aqueous solution having a sodium concentration of 50 ppm or less; flame spray pyrolyzing the silicate aqueous solution with a flame reactor to prepare nanoparticles from the silicate aqueous solution, the nanoparticles having an average particle dimension of 9 to 57 nm, and the flame reactor including five tubes: controlling the average particle dimension of the silica nanoparticles by varying the pressure of the dispersed air in the first tube from 0.5 to 2.0 kgf/cm