CHEMICALLY DURABLE IRON PHOSPHATE-GLASS WASTEFORMS

Up to 40 wt% of a simulated high level waste, whose major components w ere 54.6 wt% Na2O, 14.9 wt% P2O5 and 8.3 wt% Fe2O3, was successfully v etrified into iron phosphate wasteforms whose chemical durability was equivalent to that of borosilicate glass wasteforms. Because of their high fluidity, the iron phosphate wasteforms could be melted in as lit tle as 30 min at temperatures between 1015 degrees C and 1200 degrees C. The addition of 3-7 wt% CaF2 to the batch decreased the melting tim e and temperature, by as much as 100 degrees C, and improved the chemi cal durability, especially for crystallized iron phosphate wasteforms. Iron phosphate wasteforms are concluded to be a practical alternative for vitrifying those nuclear wastes not well suited for borosilicate glasses. (C) 1998 Elsevier Science B.V. All rights reserved.