Zirconium, Hafnium, Titanium, and Vanadium


Zirconium, Hafnium, Titanium, and Vanadium are sister metals in the Group IVA elements of the periodic table. As such, all three of these metals are chemically similar and possess similar physical properties. All are characterized by high melting points and all have high degrees of reactivity which result in the formation of extremely stable compounds such as oxides, nitrides, borides, and silicates. All three of these metals generally occur together in nature. Titanium is found as rutile or ilmenite, whereas zirconium and halfnium are usually found in zircon deposits. Ilmenite and rutile may be completely separated from zircon by physical means; however, separation of halfnium from zirconium in the zircon is a difficult chemical process. In fact, properties of the two elements are so similar that the presence of halfnium in zirconium was not recognized for over a hundred years after zirconium had been isolated.

Production of zirconium, hafnium, and titanium metals in commercial quantities has been greatly accelerated by the use of these metals in various defense efforts. Virtually all the zirconium and hafnium produced to date has been for the Naval Reactor Program. Consequently, although this program provided the incentive for preparing these new reactive metals, it has effectively restricted their availability. Titanium, produced on a large scale for high speed aircraft, became generally available at an earlier date, and a much more intensive effort has been applied to the development of its commercial applications than those of the other metals.

Whereas both zirconium and titanium are now available in a complete line of mill products, hafnium has been restricted in its application to use as a control-rod material in nuclear reactors because of its scarcity and high price. The inclusion of titanium and zirconium on the list of the less common metals can no longer be justified. Both are produced in tonnage quantities and current productive capacities exceed the predicted utilization for the next five years. In addition, both of these metals can be worked on conventional mill equipment. As a result, both titanium and zirconium are available in a wide range of mill products including ingot, billet, sheet, plate, strip, bar, rod, pipe, and tube. Both of these metals are also available in cast form.