Hafnium and Hafnium Compounds

Abstract Hafnium, Hf, is in Group 4 (IVB) of the Periodic Table as are the lighter elements, zirconium and titanium. Hafnium is a heavy gray‐white metallic element never found free in nature. It is always associated with the more plentiful zirconium. The two elements are almost identical in chemical behavior. Hafnium is obtained as a by‐product of the production of hafnium‐free nuclear grade zirconium. The refining of hafnium for its principal uses is by van Arkel‐de Boer process. Most hafnium compounds require no special safety precautions because hafnium is nontoxic under normal exposure. It is reported as having negative effect on the environment. Hafnium metal is used in alloying and in control rods for nuclear reactors. Hafnium oxide, hafnium carbide and hafnium nitride are the most important compounds of hafnium. They are the most refractory of all the compounds.