COMBUSTION SYNTHESIS OF OXIDE MATERIALS FOR NUCLEAR WASTE IMMOBILIZATION

Oxide materials like perovskite, zirconolite, hollandite, pyrochlore, NASICON and sphene which are used for nuclear waste immobilization hav e been prepared by a solution combustion process. The process involves the combustion of stoichiometric amount of corresponding metal nitrat es and carbohydrazide/tetraformyl trisazine/diformyl hydrazide at 450 degrees C. The combustion products have been characterized using powde r X-ray diffraction, infrared spectroscopy, and Si-29 MAS-NMR. The fin e particle nature of the combustion derived powders has been studied u sing density, particle size, BET surface area measurements and scannin g electron microscopy. Sintering of combustion derived powder yields 8 5-95% dense ceramics in the temperature range 1000 degrees-1300 degree s C.