Thermodynamics of the minerals of the jarosite group

Jarosite and related minerals are invariably found in natural environments acidified either through the action of acid rain or by acidic mine drainage. In spite of their importance and common occurrence, the data which could describe the solubility, precipitation, and distribution of elements between jarosite and aqueous solutions are fragmented or questionable. Here I propose to determine the thermodynamic properties (formation enthalpy, entropy, and Gibbs free energy of formation) of the jarosite group of minerals by calorimetric techniques. The measured thermodynamic quantities will be then confronted with high P-T experiments on jarosite minerals via a mathematical programming analysis. The result will be an internally consistent thermodynamic data set for jarosite group minerals. The systematics obtained will provide an excellent basis for models of dissolution, precipitation, pollutant transport, and element fractionation in environments affected by acidic input.

DFG-Verfahren Sachbeihilfen