ZIRCONIUM FLUORIDE PHASE STUDIES. I. A PRELIMINARY INVESTIGATION OF SOLID PHASES

Solid phases in the zirconium-nitric acid-hydrofluoric acid system have been identified by chemical and X-ray diffraction methods. Five different compounds have been crystallized at various temperatures and fluoride concentrations from fluoride or fluoborate solutions. These include the monoand trihydrates of zirconium tetrafluoride, plus three hydrolysis products which possess a fluoride-to-zirconium ratio of approximately three, yet produce different X-ray patterns. The trifluorides crystallize from solutions of low fluoride-to-zirconium ratio at temperatures of below 90 C, 65°-100°C, and above 95 C, respectively. Solubilities of these basic trifluorides have been measured at 25°C in 1M, 6M, and l6M nitric acid. Work done under Contract AT(l0-l)-205 to the U. S. Atomic Energy Commission.