Study of Structural and Thermal Properties of SiO2 and MgO in the Diatomite

Abstract

The diatomite still called kieselguhr is a rock formed by accumulation in old lakes, carapaces of diatoms which are fossil algae with siliceous skeleton amorphous and slightly hydrated. The diatoms are very abundant and there are several species corresponding to species different of diatomite.     In this work we determine the structural and thermal properties of SiO₂ and MgO in the diatomite using the plane wave method and linearized augmented (LAPW) in the functional theory of density (DFT). The potential for exchange and correlation is calculated by the generalized gradient approximation (GGA). For the thermal properties, we calculated the free enthalpy G, S entropy, specific heat C, thermal conductivity λ ..... etc of SiO₂ and MgO component. The temperatures used in this work are 1400, 1450 and 1500 respectively;The results are in good agreement with some experimental data.