PRODUCTS OF REACTIONS OF MO AND ZR COMPOUNDS IN MOLTEN NITRATE

Reactions of Mo and Zr compounds in molten nitrate media have been studied. It has been shown that an interaction between Zr-IV and Mo-VI species occurs in nitrate melts, leading to the formation of high-surface-area mixed-oxide solids containing dispersed molybdate species grafted onto small zirconia particles. The physico-chemical properties of the products were studied vs. reaction temperature, nature of the alkali-metal cation and Mo reactant. The reaction temperature was of primary importance in determining the composition and structure of the product. At 30 degrees C, amorphous zirconia with randomly distributed monomolybdate species was formed, whereas at 500 degrees C crystalline ZrO2 superficially modified by polymolybdate was obtained. The alkali-metal cation influenced the amount of Mo in the solid and its dispersion.