Electrochemical study on the redox behaviour of selenium-containing soda-lime-silica melts

Decolorization of white container glasses nowadays is usually achieved by t he addition of selenium compounds to the batch. Most of the quantity added, however, is evaporated during melting which is strongly influenced by the redox state of the melt. Therefore, the redox behaviour in selenium-doped s oda-lime-silica melts was studied by square-wave-voltammetry. The current-p otential curves recorded showed two peaks, attributed to the reduction of S eO3 to SeO2 and SeO2 to Se-0. Under reducing conditions, selenium predomina ntly occurs as Se-0, which gives rise to the pink color. When melted under oxidizing conditions or, however, when the melt at high temperatures for up to 50 h did not result in a notable evaporation of selenium compounds. Hig hest selenium contents were achieved by adding ZnSe to the batch.