Reaction fronts in multi-component fluid-rock interaction using analytical solutions of the Gibbs minimization problem from Thermolab

We study the systematics of reaction fronts in multi-component systems using Thermolab. The methodology is based on a finite difference approach for solving the transport problem in combination with lookup tables generated from precomputed thermodynamic equilibria covering the compositional space. The lookup tables generated from Gibbs minimization using linear programming combined with a discrete compound approach are validated against full analytical solutions of the Gibbs minimization problem. We focus on ternary ideal fluid or melt solutions in equilibrium with pure phases as exact solutions are feasible. We show that linear programming techniques yield similar results as a complete analytical solution and that both can be used in stable reactive transport codes.