Process for activating layered silicates Sud Chemie AG12/06/1996· Sud Chemie AG DE Primary Class 502/81 Other Classes 502/80 502/83 International Classes B01J20/10 B01J21/16 The dry material from calcining was moistened with 55 ml water and ground in a Retsch hammer mill mm mesh The ground material was screened to give the following sieve fractions Residue on the 63 μm sieve 25 35% Residue on the 25 μm sieve 50 60%