METHOD FOR PREPARING A SPHERE TYPE SILICA AEROGEL USING THE DROPLET FALLING SYSTEM

摘要

A method for preparing a spherical silica aerogel using a droplet falling system is provided to mass-produce spherical silica aerogel inexpensively by maximally suppressing contraction and cracking of silica aerogel beads and excluding supercritical drying, thereby enabling the silica aerogel beads to be dried in the atmospheric pressure air. A method for preparing spherical silica aerogel beads comprises the steps of: preparing a silica sol for coating by a sol-gel process; preparing spherical silica gel beads from the prepared silica sol by using a droplet falling system; aging the silica gel beads, and subjecting the aged silica gel beads to solvent replacement/surface modification; drying the silica gel beads that have completed the solvent replacement/surface modification by using an atmospheric pressure dryer; and boiling the dried silica gel beads in an n-heptane solvent at 50 deg.C for 20 minutes and at 230 deg.C for 20 minutes to heat-treat the silica gel beads, injecting the heat-treated silica gel beads into an n-heptane with a room temperature to stabilize the heat-treated silica gel beads, and heating the stabilized silica gel beads to 230 deg.C at a heating rate of 2 deg.C/min to heat-treat the silica gel beads again and obtain silica aerogel beads. The droplet falling system includes a filter having a membrane pore size of 100 mum to obtain a pure silica sol through filtration of the silica sol.