Method for producing silica aerogel blanket and silica aerogel blanket produced thereby

A method for producing a silica aerogel blanket, comprising:

• producing a silica sol;
• preparing a wet gel-base material composite by immersing a base material for a blanket in the silica sol, and adding a base to perform gelation to yield the wet gel-base material composite;
• aging the wet gel-base material composite;
• surface modifying the aged wet gel-base material composite;
• supercritical drying the surface-modified wet gel-base material composite to produce the silica aerogel blanket and a supercritical waste liquid;
• recovering the supercritical waste liquid;
• neutralizing the recovered supercritical waste liquid by adding an acid thereto to yield a recycled supercritical waste liquid;
• and
• reusing the recycled supercritical waste liquid:
• (a) in producing the silica sol;
• or
• (b) in aging the wet gel-base material composite;
• or
• (c) in surface modifying the aged wet gel-base material composite;
• or
• (d) any combination of (a)-(c),
• wherein the acid is added in an amount of 0.2 to 1.5 parts by weight based on 100 parts by weight of the recovered supercritical waste liquid.