Uraninite
Encyclopedia
Uraninite is a radioactive, uranium-rich mineral
and ore
with a chemical composition that is largely UO2
, but also contains UO3
and oxide
s of lead
, thorium
, and rare earth elements. It is most commonly known as pitchblende (from pitch, because of its black color, and blende, a term used by German
miners to denote minerals whose density suggested metal content, but whose exploitation was, at the time they were named, either impossible or not economically feasible). The mineral has been known at least since the 15th century from silver mines in the Erzgebirge Mountains, Germany. However, the type locality
is Jáchymov
in the Czech Republic
, from where F.E.Brückmann described the mineral in 1727. Pitchblende from the Johanngeorgenstadt
deposit in Germany was used by M. Klaproth
in 1789 to discover the element uranium
.
All uraninite minerals contain a small amount of radium
as a radioactive decay
product of uranium. Uraninite also always contains small amounts of the lead
isotope
s Pb-206 and Pb-207, the end products of the decay series of the uranium isotopes U-238 and U-235 respectively. Small amounts of helium
are also present in uraninite as a result of alpha decay
. Helium was first found on Earth in uraninite after having been discovered spectroscopically
in the Sun
's atmosphere. The extremely rare element technetium
can be found in uraninite in very small quantities (about 0.2 ng/kg), produced by the spontaneous fission
of uranium-238
.
Uraninite is a major ore
of uranium
. Some of the highest grade uranium ores in the world were found in the Shinkolobwe
mine in the Democratic Republic of the Congo
(the initial source for the Manhattan Project
) and in the Athabasca Basin
in northern Saskatchewan
, Canada
. Another important source of pitchblende is at Great Bear Lake
in the Northwest Territories
of Canada
, where it is found in large quantities associated with silver
. It also occurs in Australia
, Germany, England, and South Africa
. In the United States it can be found in the states of New Hampshire
, Connecticut
, North Carolina
, Wyoming
, Colorado
, Arizona
and New Mexico
.
Uranium ore is generally processed close to the mine into yellowcake
, which is an intermediate step in the processing of uranium.
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
and ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
with a chemical composition that is largely UO2
Uranium dioxide
Uranium dioxide or uranium oxide , also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used...
, but also contains UO3
Uranium trioxide
Uranium trioxide , also called uranyl oxide, uranium oxide, and uranic oxide, is the hexavalent oxide of uranium. The solid may be obtained by heating uranyl nitrate to 400 °C. Its most commonly encountered polymorph, γ-UO3, is a yellow-orange powder.-Production and use:There are three methods...
and oxide
Oxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....
s of lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, thorium
Thorium
Thorium is a natural radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 and named after Thor, the Norse god of thunder....
, and rare earth elements. It is most commonly known as pitchblende (from pitch, because of its black color, and blende, a term used by German
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....
miners to denote minerals whose density suggested metal content, but whose exploitation was, at the time they were named, either impossible or not economically feasible). The mineral has been known at least since the 15th century from silver mines in the Erzgebirge Mountains, Germany. However, the type locality
Type locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
is Jáchymov
Jáchymov
For other places called Joachimsthal, see Joachimsthal Jáchymov . compl: "Sant Joachim's Sthal" is a spa town in north-west Bohemia in the Czech Republic belonging to the Karlovy Vary Region. It is situated at an altitude of 733 m above sea level in the eponymous St...
in the Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
, from where F.E.Brückmann described the mineral in 1727. Pitchblende from the Johanngeorgenstadt
Johanngeorgenstadt
Johanngeorgenstadt is a mining town in Saxony’s Ore Mountains, 17 km south of Aue, and 27 km northwest of Karlovy Vary. It lies in the district of Erzgebirgskreis, and right on the border with the Czech Republic, is a state-recognized health resort , and calls itself Stadt des...
deposit in Germany was used by M. Klaproth
Martin Heinrich Klaproth
Martin Heinrich Klaproth was a German chemist.Klaproth was born in Wernigerode. During a large portion of his life he followed the profession of an apothecary...
in 1789 to discover the element uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
.
All uraninite minerals contain a small amount of radium
Radium
Radium is a chemical element with atomic number 88, represented by the symbol Ra. Radium is an almost pure-white alkaline earth metal, but it readily oxidizes on exposure to air, becoming black in color. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226,...
as a radioactive decay
Radioactive decay
Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...
product of uranium. Uraninite also always contains small amounts of the lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s Pb-206 and Pb-207, the end products of the decay series of the uranium isotopes U-238 and U-235 respectively. Small amounts of helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
are also present in uraninite as a result of alpha decay
Alpha decay
Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less...
. Helium was first found on Earth in uraninite after having been discovered spectroscopically
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
in the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
's atmosphere. The extremely rare element technetium
Technetium
Technetium is the chemical element with atomic number 43 and symbol Tc. It is the lowest atomic number element without any stable isotopes; every form of it is radioactive. Nearly all technetium is produced synthetically and only minute amounts are found in nature...
can be found in uraninite in very small quantities (about 0.2 ng/kg), produced by the spontaneous fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...
of uranium-238
Uranium-238
Uranium-238 is the most common isotope of uranium found in nature. It is not fissile, but is a fertile material: it can capture a slow neutron and after two beta decays become fissile plutonium-239...
.
Uraninite is a major ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
of uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
. Some of the highest grade uranium ores in the world were found in the Shinkolobwe
Shinkolobwe
Shinkolobwe is the name of a town and a mine in the Katanga province of the Democratic Republic of the Congo , located near the larger town of Likasi and about 120 miles northwest of Lubumbashi. The former mine was located in the centre of a 400 kilometre long belt of uranified minerals, stretching...
mine in the Democratic Republic of the Congo
Democratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...
(the initial source for the Manhattan Project
Manhattan Project
The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...
) and in the Athabasca Basin
Athabasca Basin
This article is about the uranium mining region near Lake Athabasca. Not to be confused with the drainage basin of the Athabasca River.The Athabasca Basin is a region of Northern Saskatchewan and Alberta Canada that is best known as the world's leading source of high grade uranium...
in northern Saskatchewan
Saskatchewan
Saskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. Another important source of pitchblende is at Great Bear Lake
Great Bear Lake
Great Bear Lake is the largest lake entirely within Canada , the third or fourth largest in North America, and the seventh or eighth largest in the world...
in the Northwest Territories
Northwest Territories
The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...
of Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, where it is found in large quantities associated with silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
. It also occurs in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, Germany, England, and South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. In the United States it can be found in the states of New Hampshire
New Hampshire
New Hampshire is a state in the New England region of the northeastern United States of America. The state was named after the southern English county of Hampshire. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Atlantic Ocean to the east, and the Canadian...
, Connecticut
Connecticut
Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...
, North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
, Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
and New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
.
Uranium ore is generally processed close to the mine into yellowcake
Yellowcake
Yellowcake is a kind of uranium concentrate powder obtained from leach solutions, in an intermediate step in the processing of uranium ores. Yellowcake concentrates are prepared by various extraction and refining methods, depending on the types of ores...
, which is an intermediate step in the processing of uranium.
See also
- ThorianiteThorianiteThorianite is a rare mineral, originally discovered by Ananda Coomaraswamy in 1904 as uraninite, but recognized as a new species by Wyndham R. Dunstan. It was so named on account of its high percentage of thorium ; it also contains the oxides of uranium, lanthanum, cerium and didymium...
- Uranium ore deposits
- List of minerals
- List of uranium mines