The morphology of hydrothermally synthesized gonnardite

Abstract

The hydrothermal treatment of glasses of the composition 5 Na₂O : 4 CaO : 9 Al₂O₃ : 22 SiO₂ at 1 kbar pressure in a temperature range between 80°C and 200°C leads to the formation of the zeolite mineral gonnardite (NAT) with orthorhombic symmetry (a = 13.35 Å, b = 13.35 Å, and c = 6.65 Å). The formation of the mineral phase under these equilibrium conditions is restricted to the temperature interval between 80°C and 150°C.