Thermodynamics of the redox reactions between the oxygen and the oxides of the polyvalent elements in glass melts

Abstract

The redox reaetions (RR) in glass melts, containing oxides of different polyvalent elements are analysed. In the following oxides of polyvalent elements are considered and not the corresponding ions as reaction partners of the type: xRed + zO₂ = yOx, where Red and Ox are the oxides. The enthalpies is ΔHt of these RR are defmed using experimental data for various RR on the basis of thermodynamic equations and compared with the appropriate Standard enthalpies ΔH⁰t. The ratio x_(οx)/x_(Red) is analysed as a function of the sum ( x_(ox) + x_(Red)), where x_(ox) and x_(Red) are the mole fractions of the oxides Ox and Red. The obtained equation is compared with the experimental data available for the iron oxides.