Equilibrium constant - determination and influence on redox reactions in soda-lime-silica glass melts

Abstract

The iron, arsenic and chromium redox equilibrium in an oxide glass-forming melt has been studied quantitatively The equilibrium constant K(T) and the thermodynamic Standard values were determined for the redox reaction in the melt at temperatures between 1000 and 1450 °C. These values were compared with values from the literature. The equilibrium constant is dependent on the temperature and on the concentration of the polyvalent elements. This dependence applies to the polyvalent elements investigated. For each polyvalent element it is possible to find a step in the funcdon lg([R^y]/[R^x) versus R_aO_b- This seems to be explained by the concentradon dependence of the equilibrium constant of the redox reaction. Possibilities to determine the equilibrium constants of the various polyvalent elements are described.