Patent ID: 6372709
Filing Date: 2002-04-16
Classification: C01B,C11D

Abstract:
A finely divided crystalline layered sodium disilicate of the formulaNaMSixO2x+1yH2O, where M is sodium or hydrogen, x is a number from 1.9 to 4, and y is a number from 0 to 20, which comprises from 0 to 40% by weight of alpha-disodium disilicate from 0 to 40% by weight of beta-disodium disilicate, from 40 to 100% by weight of delta-disodium disilicate, from 0 to 40% by weight of amorphous components, said layered silicate having a calcium-binding capacity of more than 170 mg of CaCO3/g at 30Â° C. and 17Â° German hardness, and said layered silicate having a sieve residue of less than 60%, wherein said layered silicate is obtained by a process which comprises grinding a sodium phyllosilicate having a particle diameter d50 of from 80 to 400 &mgr;m to a d90 value of less than 100 &mgr;m.