Reactions of Zr(SO4)2 in molten nitrite and nitrate systems

Abstract

The reactions of anhydrous Zr(SO₄)₂ in different nitrite and nitrate melts were studied by TG, DTG and DTA methods. It was found that Zr(SO₄)₂ reacted in nitrate melts in multiple stages, whereas the reaction of Zr(SO₄)₂ in the NaNO₂–KNO₂ system took place in only one stage, the reaction mechanism being second order with an apparent activation energy of about 183 kJ mol^–1. The stoichiometries and the processes of the reactions are also discussed. X-Ray results indicated that the powders produced from the nitrate melts were a mixture of the monoclinic and tetragonal phases, while from nitrite melts only the tetragonal structure was formed.