The Development of a Simple Method for the Preparation of Reactor-Grade Zirconium

Abstract

The separation of zirconium and hafnium by the fractional precipitation method has been extended by coprecipitation of their pyrophosphates. In the presence of sulfate ion, fractional precipitation of zirconium-hafnium pyrophosphates from a solution in 4 N HCI gives a good separation factor. Hafnium becomes concentrated in the precipitate. At a concentration of 0.7 to 0.8 g Zr/100 ml, optimum results were obtained with the addition of about 50 g ammonium sulfate/100 ml (Λ > 5). The separation factor falls sharply at higher concentrations of zirconium. Moreover, it has been found that when precipitation of the host is done above 45%, the separation factor shows a declining trend. It was, therefore, not possible to prepare reactor-grade zirconium in a single stage. After several trials it was possible to find nearly optimum conditions for the separation. Finally, reactor-grade zirconium was obtained in three stages of precipitation with an yield of ～24%.