Applications
Zirconium is used in alloys such as zircaloy, which is used in nuclear
applications since it does not readily absorb neutrons. Also used in catalytic
converters, percussion caps and furnace bricks. Baddeleyite and impure Zirconium
(zirconia) are used in lab crucibles.
The major end uses of zircon (ZrSiO4) are refractories, ceramic opacification
and foundry sands. Zircon is also marketed as a natural gemstone used in
jewelry. The metal also has many other uses, among them in photographic
flashbulbs and surgical instruments, to make the glass for television, in the
removal of residual gases from electronic vacuum tubes, and as a hardening agent
in alloys, especially steel. The paper and packaging industries are finding that
Zirconium compounds make good surface coatings because they have excellent water
resistance and strength.
Zirconium in the environment
Zirconium is not a particularly rare element but because its most common
mineral, zircon, is highly resistant to weatering it is only slightly mobile in
the environment. Zirconium is more than twice as abundant as Copper and Zinc and
more than 10 times more abundant than lead.
The chief ores are zircon (ZrSiO4), which is mined in Australia, USA and Sri
Lanka, and baddeleyite (Zirconium oxide ZrO2) which is mined in Brasil. World
production is in excess of 900.000 tonnes per year of zircon, and 7000 tonnes of
the metal are produced. The estimated reserves exceed a billion tonnes.
Australia, South Africa, India, Sri Lanka and the USA have vast deposits of
zircon and zirconia sands.
Health effects of Zirconium
Zirconium and its salts generally have low systemic toxicity. The estimated
dietary intake is about 50 microg. Most passes through the gut without being
adsorbed, and that which is adsorbed tends to accumulate slightly more in the
skeleton than in tissue.
Zirconium 95 is one of the radionuclides involved in atmospheric testing of
nuclear weapons. It is among the long-lived radionuclides that have produced and
will continue to produce increased cancers risk for decades and centuries to
come.
Environmental effects of Zirconium
Zirconium is unlikely to present a hazard to the environment.
While aquatic plants have a rapid uptake of soluble Zirconium, land plants have
little tendency to adsorb it, and indeed 70% of plants that have been tested
showed no Zirconium to be present at all.
