- CAS [65997-17-3] - EINECS-No.: 266-046-0 - Solub. in water: (20 ºC): insoluble - Tariff number: 7019 90 00 90 SPECIFICATIONS soluble alkali in water (as Na2O): max. 0,1 % solubility in HCl: max. 1 % diameter of fibre: passes test