Composition effects on microstructure in heat-treated Fernald waste glasses

Several ratios of Fernald pit sludge to contaminated soil have been combined with a variety of low-cost additives to find an acceptable composition range of vitrification of Fernald waste. Heat-treatment of many test compositions has produced an array of fluorosilicate, pyroxenes, and a few other phases. The authors report here on the specific effects of key components contributed by the wastes, especially MgF2, and of potential additives (Al2O3, B2O3, Na2O, SiO2, etc.) on the amount and types of crystalline phases forming during heat treatment and comment on the implications of these results with respect to composition optimization for processability and durability. 6 refs., 7 figs., 3 tabs