Kinetic model of silicate melts - Equilibrium case

Abstract

Basing on the experimental evidence that in silicate melts silicon is always tetrahedrally coordinated by oxygen and that these structural units principally are able to form polyanionic structures by sharing oxygen atoms between two tetrahedra a kinetic model for the description of silicate melts is developed. As basic kinetic events in such systems the diffusive motion of individual poly anions and the interchange of structural units between different poly anions by condensation and splitting reactions are taken into account. The balance relations formulated for each polyanionic species separately lead to a system of differential equations which are coupled through the reaction terms. The calculation of polyanion distributions corresponding to a dynamical equilibrium is possible and allows principally the estimation of the degree of branching and intramolecular condensation in the melt.