Review of processes for the production of hafnium-free zirconium.

Abstract

The three main industrial processes for the production of hafnium-free zirconium are described in terms of their head-end, zirconium-hafnium separation and zirconium metal forming steps. Possible improvements and alternative processes are outlined. Zirconium-hafnium separation schemes based on selective reduction of the chlorides or distillation and sublimation techniques show the most promise for future development in competition with the established hexone-thiocyanate and TBP-nitric acid solvent extraction schemes. Head-end steps involving direct chlorination of zircon in fluidised beds or caustic fusion and metal production via electrowinning warrant further development.