Uranium

In ancient times uranium oxide was used to produce yellow colored ceramic glazes. Uranium was formally discovered in 1789 by Martin Heinrich Klaproth. Klaproth was studying the mineral pitchblende, which was then believed to be a zinc/iron ore. Klaproth dissolved pitchblende in nitric acid, then added potash to obtain a yellow precipitate. Adding excess potash dissolved the yellow precipitate. Such reactions were not characteristic of any known element and Klaproth concluded he had discovered a new element. ⁽¹⁾ He named it after the recently discovered planet Uranus. In 1841, Eugene-Melchior Peligot isolated uranium metal by heating uranium tetrachloride with potassium.

Uranium is harmful both through its chemical toxicity and its radioactivity. Exposure to uranium increases your risk of getting a variety of cancers due to its radioactivity.

Uranium is a dense, silvery-white, slightly paramagnetic, radioactive metal. It is also ductile and malleable. The metal tarnishes in air acquiring a dark layer of oxide. When finely powdered, uranium ignites spontaneously in air.

Uranium is a highly reactive metal and reacts with almost of all the nonmetallic elements and many of their compounds. It dissolves in acids, but it is insoluble in alkalis.

All isotopes of uranium are radioactive, some more so than others. Its radioactivity - in particular its capacity to undergo thermonuclear chain reactions - has led to uranium's use in energy generation, both for civilian and military purposes.

Uranium is used as fuel for nuclear power plants. One kilogram of uranium-235 has the capacity to produce as much energy as 1,500,000 kilograms (1,500 tonnes) of coal.

Naturally occurring uranium is over 99 % U-238 with only about 0.7 % of the fissile U-235. Huge gas diffusion plants are used to produce enriched uranium, which has higher concentrations of U-235.

Uranium for use in nuclear power plants is enriched to a U-235 concentration of 2-3 %.

In nuclear weapons, it is believed uranium is enriched to about 90% U-235, although lower concentrations would still yield a working bomb.

Depleted uranium is a byproduct of enriching uranium for nuclear purposes. It contains only about 0.2 % U-235 and is only a little over half as radioactive as naturally occurring uranium. Its lower radioactivity has allowed depleted uranium to be used in applications where uranium's very high density is useful. (A tennis ball sized sphere of uranium would weigh about 5.7 pounds (2.6 kilograms).) It is used by the military as shielding to protect army tanks, and also in parts of bullets and missiles.

Use of depleted uranium in missiles is controversial because, on impact, uranium vapor and dust form and these are highly toxic.

U-238 can be converted into fissionable plutonium in breeder reactors.

Uranium occurs naturally in several minerals such as uraninite (uranium oxide), carnotite and autunite. Canada is the world's largest supplier of uranium, producing 20 to 30 percent of supplies. ⁽²⁾ Commercially, uranium is produced through the reduction of uranium halides with alkali earth metals. Although most people think uranium is extraordinarily rare, it is in fact more abundant than famil

Uranium has 21 isotopes whose half-lives are known, with mass numbers 218 to 242. Natural uranium consists of three major isotopes: ²³⁴U, ²³⁵U, and ²³⁸U. All are radioactive. ²³⁸U is the most stable isotope, with a half-life of 4.51 x 10⁹ years (almost the age of the Earth).