Zirconium

 

Zirconium, the metal extracted from the mineral, zircon, may not be well-known, but its remarkable properties make it indispensable in nuclear power, the chemical industry, medicine and more. Since ancient times, zircon — a word believed to have originated from the Persian zargun, meaning gold-like — has been used in jewellery and decorations.

The IAEA has released The Metallurgy of Zirconium, a three-volume publication offering a comprehensive overview of the metal, its extraction, properties and applications in nuclear energy. Here are five interesting facts about zirconium.

1. Zirconium is a shiny silver-grey metal

It is highly ductile and extremely resistant to corrosion and heat. Its symbol in the periodic table is Zr, and its atomic number is 40. It melts at 1855 degrees Celsius (°C) and boils at 4409 °C, and it is not corroded by acids, alkalis or seawater.

2. The mineral zircon is relatively widespread on the Earth’s surface

Zirconium is primarily extracted from the mineral zircon which is often found in the sands of coastal waters. The mineral is not contained in concentrated deposits, but rather broadly dispersed inside the ground. Today, the major producers of zirconium include Australia, China, Indonesia, South Africa and Ukraine. Beyond Earth, the element has been identified in the stars, including the Sun, and in lunar rocks.

3. Zirconium was discovered in 1789

Zirconium was identified by German chemist Martin Klaproth in a zircon stone brought from Sri Lanka. Pure zirconium — metal not mixed or alloyed with other elements — was first produced in 1925. But it was not widely used in industry until the end of the 1940s when it became an important engineering material used in producing nuclear energy.

4. Zirconium is mainly used in nuclear power

Zirconium is indispensable in the production of nuclear energy, particularly as a cladding for long cylindrical fuel rods inside nuclear reactors. There are several reasons why zirconium is an optimal material to surround uranium pellets: the metal is exceptionally resistant to corrosion and high temperatures, and it absorbs very few of the neutrons produced by a nuclear fission reaction. The latter is essential for the chain reaction to run effectively inside the reactor’s core and to sustain the production of energy.

By cladding uranium fuel, zirconium also helps protect the coolant, typically water flowing through the reactor core, from contamination. It is estimated that up to 90 per cent of zirconium produced in the world is used for nuclear power.

5. While most zirconium is used in the nuclear field, it is not limited to that

Being tremendously resistant to corrosion by many acids and alkalis, it is broadly employed in the chemical industry. Zirconium compounds are used in ceramics, abrasives, lamp filaments, jet engines and space shuttle parts. In the medical field, zirconium dioxide, also known as zirconia, is applied as a material for dental and surgical implants due to its biocompatibility and durability. Zirconia is also used as a gemstone — cubic zirconia — a synthesized material that can be a substitute for diamonds and other precious stones.

 

Want to know more about zirconium?

The IAEA’s new publication The Metallurgy of Zirconium is your go-to source. Over three volumes, the book — unique in its scope and breadth — provides readers in industry and academia with a comprehensive review of the development and understanding of zirconium within the context of its use in nuclear reactors. It presents input from leading experts in the relevant fields and encompasses the full spectrum of zirconium as a metal, its properties and its use.

 

The publication’s coverage includes alloy development in the nuclear industry and guidelines on commercial alloys and alloys under development; extraction and consolidation of zirconium, from ore to ingot to component; deformation and texture of various alloys with analysis of the effects of irradiation damage on physical and mechanical behaviour as well as deformation and creep during irradiation and damage due to oxidation and corrosion; and ductility and fractures of alloys.

 

“The future of the nuclear industry worldwide depends primarily on the ability of the nuclear community to further improve our understanding of the materials used in the industry,” said Anzhelika Khaperskaia, Technical Lead at the IAEA Division of Nuclear Fuel Cycle and Waste Technology and current Scientific Secretary responsible for the publication of the book.