Zirconium (
/zərˈkoʊniəm/ zər-KOH-ni-əm)
is a chemical element with the symbol Zr and atomic
number 40. Its atomic mass is 91.224. It is a lustrous, grey-white,
strong transition metal that resembles titanium.
Zirconium is used as an alloying agent for its strong resistance to corrosion.
It is never found as a native metal; it is obtained mainly from the mineral zircon,
which can be purified with chlorine.
Zirconium was first isolated in an impure form in 1824 by Jöns Jakob Berzelius.
Detailed description
Zirconium has no
known biological role. Zirconium forms both inorganic and organometallic
compounds such as zirconium dioxide and zirconocene
dichloride,
respectively. There are five naturally occurring isotopes, three of which are stable.
Short-term exposure to zirconium powder causes minor irritation, and inhalation
of zirconium compounds can cause skin and lung granulomas.
|
Characteristics
Zirconium is a lustrous, grayish-white, soft, ductile, and malleable metal which is solid at room
temperature, though it becomes hard and brittle at lower purities.[4][5] In powder form, zirconium is highly
flammable, but the solid form is far less prone to ignition. Zirconium is
highly resistant to corrosion by alkalis, acids, salt water, and other agents.[6] However, it will dissolve in hydrochloric and sulfuric acid, especially when fluorine is present.[7] Alloys with zinc become magnetic
below 35 K.[6]
Zirconium's
melting point is at 1855°C, and its boiling point 4409°C.[6] Zirconium has an electronegativity of 1.33 on the Pauling scale. Of the
elements within d-block, zirconium has the fourth lowest
electronegativity after yttrium, lutetium, and hafnium.[8]
Applications
Because of
zirconium's excellent resistance to corrosion, it is often used as an alloying
agent in materials that are exposed to corrosive agents, such as surgical
appliances, explosive primers, vacuum tube getters and filaments. Zirconium dioxide (ZrO2)
is used in laboratory crucibles, metallurgical furnaces, as a refractory
material,[6] and it can be sintered into a ceramic knife. Zircon (ZrSiO4) is cut into gemstones for
use in jewelry. Zirconium carbonate (3ZrO2·CO2·H2O)
was used in lotions to treat poison ivy, but this was discontinued because it
occasionally caused bad skin reactions.[4]
Ninety percent of
all zirconium produced is used in nuclear reactors (in the form of zircaloys) because of its low neutron-capture cross-section and resistance to corrosion.[5][6] Zirconium alloys are used in space
vehicle parts for their resistance to heat, an important quality given the
extreme heat associated with atmospheric
reentry.[9] Zirconium is also a component in some
abrasives, such as grinding wheels and sandpaper.[10] Zirconium is used in weapons such as
the BLU-97/B Combined Effects Bomb for incendiary effect.
High temperature
parts such as combustors, blades and vanes in modern jet engines and stationary
gas turbines are to an ever increasing extent being protected by thin ceramic
layers which reduce the metal temperatures below and keep them from undergoing
(too) extensive deformation which could possibly result in early failure. They
are absolutely necessary for the most modern gas turbines which are driven to
ever higher firing temperatures to produce more electricity at less CO2.
These ceramic layers are usually composed by a mixture of zirconium and yttrium
oxide.[11]
Refining
Upon being
collected from coastal waters, the solid mineral zircon is purified by spiral concentrators to remove
excess sand and gravel and by magnetic separators to remove ilmenite and rutile. The byproducts can then be dumped back into
the water safely, as they are all natural components of beach sand. The refined
zircon is then purified into pure zirconium by chlorine or other agents, then sintered until sufficiently ductile for metalworking.[5] Zirconium and hafnium are both contained in zircon and they
are quite difficult to separate due to their extremely similar chemical
properties. Usually, an ion exchange process is used to separate them.
PRICE
$45/KG
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
Comments
Post a Comment