Solid oxide electrolyte emf cell determination of the standard free energy of Cr2O3 and applications to chromium-bearing mineral systems

Abstract

Emf measurements are reported on cells using a thoria-yttria solid oxide electrolyte. The measured potentials from two cells, Cr, CraO, IThO,-Y,Os) Co, COO and Cr, Cr,Oa IThO,-Y203\ Mn, MnO, were used to calculate the standard Gibbs free energy of formation of Cr,Oa in the temperature range 875-1275%. The two separate series of measurements are in good agreement with critically assessed data from the literature based on gas equilibration and calorimetric results. A summary of solid oxide electrolyte studies on mineral systems is presented with special attention paid to chromium-bearing solutions or compounds. The application of this experimental technique in investigating thermodynamic properties of chromium minerals is discussed: