Patent ID: 6017505
Filing Date: 2000-01-25
Classification: B01J,C01B,Y02P

Abstract:
In a process for preparing inorganic aerogel granules based on oxides of at least one metal selected from the group consisting of magnesium, aluminum, silicon, tin, lanthanum, titanium, zirconium, chromium and thorium by producing hydrogel granules in a sol-gel process, replacing the water in the hydrogel granules by an organic solvent, removing the organic solvent from the hydrogel to produce a solvent moist hydrogel, and drying the solvent moist gel granules, the improvement comprising:very rapidly drying the gel granules by heating the solvent-moist gel to a temperature above the normal atmospheric pressure boiling point of the solvent but below its pyrolysis temperature and at a pressure which is below the supercritical pressure of the solvent thereby rapidly evaporating remaining solvent within 20 seconds, andrecovering a dried granule product.