Zirconium – The element
The name zirconium is taken from the mineral zircon, the oldest known mineral on our earth’s crust and the most important source of zirconium. Zirconium is not found in nature as a native metal but as a zirconium silicate (ZrSiO4). Zircon is mainly mined as a by-product of titanium mining in Australia and South Africa.
Zirconium is a transition element with the atomic number 40. It is grouped together with titanium and hafnium in Group IV B of the Periodic Table. The similarity in the electron structure of these elements is the reason all three have similar chemical and physical properties. Zirconium is particularly closely related to hafnium and these two elements always occur together in nature.
Zirconium is the oldest and 12th most abundant element in terrestrial rocks. Analyses of lunar rock samples collected during the Apollo missions found relatively high levels of zirconium oxide content. Zirconium has also been identified in S-type stars, the sun and meterorites.
Zirconium is a lustrous, grey, soft and ductile metal which is a solid at room temperature. It is highly resistant to corrosion by alkalis, acids and salt water however it dissolves in sulphuric and hydrochloric acids.
The melting point of zirconium is 1855 degC and its boiling point is 4371 degC.