Investigations into the existence of hexavalent chromium in industrial glasses

Abstract

In several melting experiments the existence of hexavalent chromium in soda-lime-silica glasses depending on the oxidation conditions and the presence of iron have been investigated by means of a recently proposed wet chemical analysis procedure. The observed dependence of the concentraüon of hexavalent chromium on the iron content can be explained by means of an electron exchange between iron and chromium during cooling. The results have been applied to the conditions of industrial glass melting. Under sufficiently reducing conditions and high portions of iron the existence of hexavalent chromium can be excluded. These conditions are fulfilled for all commercial container glasses investigated.