Phase diagram of kaolinite from Molecular Dynamics calculations

Structural and thermal behaviors of uncharged 1:1 phyllosilicates kaolinite were investigated from molecular dynamics simulations based on the CLAYFF force field. The focus is on the variation of structural properties including bulk modulus with pressure from 0 to 20 GPa under various range of temperature. The largest bulk modulus between the pressures of 200 and 800 MPa varies from 80 GPa at 298 K to 50 GPa at 1473 K. The obtained value of C-p varies between 7.8 and 13.6 Kcal mol(-1) K-1 in the pressure range of 0.1 MPa-20 GPa. Besides, a huge difference was noticed regarding the computed properties at the superheating point. Finally, we show the relationship between superheating point temperature and pressure leading to a phase diagram of kaolinite. (C) 2012 Elsevier B.V. All rights reserved.