Abstract:
Nitrate replaced alkoxide and alcohol solvent omitted, a TEOS-KNO
3-Al(NO
3)
3-H
2O system turned into gel in 5~12 min with pH adjusted by aqua ammonia. Dried gel treated at 862℃, pure and homogeneous kalsilite powder was prepared with an average particle size of 8μm. The TEOS hydrolysis reaction was catalyzed by H
+ released from aluminum nitrate hydrolysis firstly, and then promoted again by OH
- with the addition of aqua ammonia. The gelation time was shortened greatly owing to the catalysis mode of acid first and alkali second. A penta-coordination Al was detected by
27Al NMR analyzing the dried aluminosilicate gel.