Redox behavior of iron and vanadium ions in Silicate melts at temperatures up to 2000 °C

Abstract

Two glasses 33Na₂O · 67SiO₂ and 15Na₂O · 85SiO₂ (composition in mol%), doped with Fe₂O₃ and V₂O₅, respectively, were melted under various conditions in the temperature ränge of 1400 to 2000 °C. The redox states in the quenched glasses were investigated by optical absorption spectroscopy. Investigations concerning the redox equilibrium of the polyvalent ions in the glass melts were carried out using square-wave voltammetry. The results of both methods were compared. Furthermore equilibrium experiments were carried out to show the time dependence of redox equilibrium reached.