Rick Dietrich, 12, of Lynn, Mass., for her question:
WHERE IS URANIUM FOUND?
Uranium is the main source of nuclear energy. The element has the highest atomic weight found in nature. The United States is the leading uranium producing country in the world with Wyoming, New Mexico, Ontario, Texas, Colorado, Utah and Saskatchewan, in order, the leading uranium producin(. states and provinces.
Uranium is not a rare mineral. It is more common in earth than such so called common elements as mercury, silver and iodine. But the concentration of uranium in most rocks is only a few parts in a million.
Pitchblende is the richest uranium ore. It is a dark blueish black mineral with a pitchlike luster. The richest deposits of almost pure pitchblende in Africa have largely been used up.
The most important ore found in the United States is carnolite, a compound of uranium with vanadium, potassium and oxygen.
Due to its importance as a source of nuclear energy, uranium has been vigorously sought since the end of World War II. Large amounts exist in shale and phosphate deposits, in granites and in the ocean, but much of it cannot be recovered at a reasonable cost.
Uranium ore goes from the mines to uranium concentrating plants. Here, impurities are removed after crushing and the uranium is converted into an oxide of uranium. Then, in other plants, the uranium oxide is refined to either a metal powder of pure uranium or the compound uranium hexafluroide.
The uranium metal may be used in nuclear reactors to produce plutonium.
Pure uranium is a silvery metal, softer than iron. It is a member of the actinide series of elements. This series has actinium as its lightest weight member.
Uranium is very reactive. It combines vigorously with oxygen and is pyrophoric. This means that small chips of the metal may burn spontaneously in air, as magnesium does.
Uranium forms several different oxides and it will decompose water.
A German scientist named Martin Klaproth was the first to discover an oxide of uranium in the mineral pitchblende. This happened in 1789. He named the element in honor of the discovery of the planet Uranus.
Even though it was first discovered in 1789, it wasn't until 1842 that the element was isolated.
After the United States, the leading uranium producing countries, in order, include Canada, South Africa, France, Niger, Gabon and Spain.
The compound uranium hexafluroide is sent to gaseous diffusion plants where U 235 is produced.
As found in nature, uranium consists of a mixture of three isotopes. Isotopes are atoms of an element that have the same atomic number but different atomic weight or mass numbers.