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Topic: Thorium


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In the News (Sun 22 Nov 09)

  
  ATSDR - ToxFAQs™: Thorium
Thorium is used to make ceramics, gas lantern mantles, and metals used in the aerospace industry and in nuclear reactions.
Liver diseases and effects on the blood were found in people injected with thorotrast, a thorium compound injected into the body as a radiographic contrast medium between the years 1928 and 1955.
People who had large amounts of thorium injected into their blood for special x-ray tests had more than the usual number of liver tumors, cancers of the blood, such as leukemia, and tumors of the bone, kidney, spleen, and pancreas.
www.atsdr.cdc.gov /tfacts147.html   (937 words)

  
  Thorium - Wikipedia, the free encyclopedia
Thorium is a chemical element in the periodic table that has the symbol Th and atomic number 90.
Thorium is used to coat tungsten wire used in electronic equipment, improving the electron emission of heated cathodes.
Thorium is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium, and is about as common as lead.
en.wikipedia.org /wiki/Thorium   (1100 words)

  
 thorium. The Columbia Encyclopedia, Sixth Edition. 2001-05
Thorium is widely distributed in small amounts in the earth’s crust, being about half as abundant as lead and three times as abundant as uranium.
Thorium metal is isolated with difficulty; it is obtained from certain of its compounds by electrolysis or by chemical reduction.
Thorium was discovered in 1828 by Jöns Jakob Berzelius but had few uses until the invention of the Welsbach mantle in 1885.
www.bartleby.com /65/th/thorium.html   (558 words)

  
 Thorium dioxide - Wikipedia, the free encyclopedia
The compound is radioactive due to the radioactivity of thorium.
Thorium dioxide was the primary ingredient in the X-ray contrast medium Thorotrast.
Thorium dioxide is used as a stabilizer in tungsten electrodes in TIG welding and electron tubes.
en.wikipedia.org /wiki/Thorium_dioxide   (393 words)

  
 Thorium (Th)   (Site not responding. Last check: )
Thorium occurs in thorite, in orangite and in thorianite.
Thorium metal is used as a stabilizing component of electronic tubes and in magnesium alloys.
Thorium oxide is used in light filaments, electrodes and glasses that have a high refractive index and low dispersion.
www.bayerus.com /msms/fun/pages/periodic/thorium   (200 words)

  
 Principal Metals-Thorium
Several methods are available for producing thorium metal; it can be obtained by reducing thorium oxide with calcium, by electrolysis of anhydrous thorium chloride in a fused mixture of sodium and potassium chlorides, by calcium reduction of thorium tetrachloride mixed with anhydrous zinc chloride, and by reduction of thorium tetrachloride with an alkali metal.
The physical properties of thorium are greatly influenced by the degree of contamination with the oxide.
Thorium is an important alloying element in magnesium, imparting high strength and creep resistance at elevated temperatures.
www.principalmetals.com /utilities/90.htm   (678 words)

  
 thorium
Thorium occurs in thorite (ThSiO4) and in thorianite (ThO2 + UO2).
Thorium is dimorphic, changing at 1400 deg C from a cubic to a body-centered cubic structure.
Plant/soil concn ratios for uranium and thorium isotopes were estimated for (1) exposed, weather tailings, (2) the edge of a tailings impoundment, (3) an area downwind from exposed tailings, (4) a reclamation area and (5) several background, native range locations.
www.speclab.com /elements/thorium.htm   (2126 words)

  
 EPA - Thorium - Information Home (EPA's Radiation Protection Program: Information)   (Site not responding. Last check: )
Thorium occurs at very low levels in virtually all rock, soil, and water, and therefore is found in plants and animals as well.
Thorium improves the properties of ophthalmic lenses, and is an alloying agent in certain metals used in the aerospace industry.
EPA protects people and the environment from thorium by establishing standards for the clean-up of contaminated sites, and by setting limits on the amount of thorium (and other radionuclides) that may be released to the air from specific sources, or found in public drinking water.
www.epa.gov /radiation/radionuclides/thorium.htm   (1317 words)

  
 The Elements: Thorium
Several methods are available for producing thorium metal; it can be obtained by reducing thorium oxide with calcium; by electrolysis of anhydrous thorium chloride in a fused mixture of sodium and potassium chlorides; by calcium reduction of thorium tetrachloride mixed with anhydrous zinc chloride; and by reduction of thorium tetrachloride with alkali metal.
Thorium is dimorphic, changing at 1400 C from a cubic to a body-centered cubic structure.
Thorium oxide has a melting point of 3300 C, which is the highest of all oxides.
www.cmbi.kun.nl /~ott/elements/thorium.html   (719 words)

  
 Wikinfo | Thorium   (Site not responding. Last check: )
Thorium is used to coat tungsten wire used in electronic equipment.
Thorium oxide added to glass helps create glasses of a high refactive index and with low dispersion.
Thorium was discovered in 1828 by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of war.
www.wikinfo.org /wiki.php?title=Thorium   (908 words)

  
 C&EN: IT'S ELEMENTAL: THE PERIODIC TABLE - THORIUM
Thorium is the most efficient nuclear reactor fuel, so there have been many attempts to produce reactor fuel from thorium, including current unrelated efforts by Thorium Power and by institutes in India.
In addition, fuels that burn plutonium without thorium actually produce large quantities of new weapons-suitable plutonium in the spent fuel; this is not the case with thorium fuel.
Thorium is primarily obtained from the minerals thorite and thorianite.
pubs.acs.org /cen/80th/thorium.html   (796 words)

  
 Low-Energy Nuclear Transformation: Where Did The Thorium Go?
The thorium solution is chemically tested to determine the amount of thorium (4300 parts per million with 0.1 grams of thorium in a 25 ml solution).
From the weight of the precipitates, and the concentration of the thorium, it was calculated that 2.57% of the thorium originally introduced into the reactor was present in the precipitates.
It is hypothesized that the neutron-rich thorium will produce nuclear fragments that are neutron rich (isotopes lying to the higher neutron end of a line of elemental isotopes) and that such isotopes will decay to stable elements by beta-emission (the changing of a neutron to a proton by the emission of a high-energy electron).
www.padrak.com /ine/NEN_5_10_2.html   (1437 words)

  
 Thorium (John De Armond)   (Site not responding. Last check: )
Thorium is one of the heavy, mildly radioactive transuranic elements, located in actinic row of the periodic table along with uranium plutonium and several other interesting metals.
Thorium is a nuclear fuel and can be transmuted into U-233 by neutron bombardment.
Thorium oxide is an excellent refractory, having one of the highest melting points of all substances and having excellent thermal conductivity.
yarchive.net /nuke/thorium.html   (390 words)

   1" rowspan="1"> 90 1" rowspan="1"> Th 1" rowspan="1"> Thorium 1" rowspan="1"> 232.0381 1" rowspan="1"> 2 ·â€‰8 ·â€‰18 32 ·â€‰18 10 ·â€‰2
 thorium articles on Encyclopedia.com   (Site not responding. Last check: )
Periodic Table of the Elements: Thorium PERIODIC TABLE OF THE ELEMENTS: THORIUM [Periodic Table of the Elements: Thorium] Periodic Table of the Elements: Thorium
thorium THORIUM [thorium] [from Thor ], radioactive chemical element; symbol Th; at.
Welsbach mantle WELSBACH MANTLE [Welsbach mantle] or Welsbach burner [for C. von Welsbach ], cylindrical framework of gauze impregnated with oxides of thorium and cerium.
www.encyclopedia.com /articles/12832.html   (372 words)

  
 Supplier Data — Thorium (Th) (Goodfellow)
Thorium is a dark grey, radioactive metal of which the principal source is the ore, monazite, a complex phosphate of thorium, uranium, cerium and lanthanides.
Thorium is used as an alternative reactor fuel to uranium, thorium being converted readily into uranium in the reactor.
Thorium is extremely efficient as an energy source, the earthly reserves of thorium containing more energy than all other fossil fuel sources combined.
www.azom.com /details.asp?ArticleID=1832   (178 words)

  
 HTGCR-thorium-NH3   (Site not responding. Last check: )
Thorium 232 is not fissionable, but it can be converted to fissionable U233 with thermal (slow, moderated) neutrons, unlike U238 which is converted to plutonium with fast unmoderated neutrons in liquid sodium cooled reactors which endure much corrosion which can lead to danger like loss of coolant.
Thorium breeders using thermal neutrons combined with electronuclear breeders could be the way of the future.
Thorium ore is far richer than uranium ore and this could be a way to dispose of weapons plutonium stockpiles.
www.moonminer.com /HTGCR-thorium-NH3.html   (2652 words)

  
 World Nuclear Association | Information and Issue Briefs | Thorium
Thorium is a naturally-occurring, slightly radioactive metal discovered in 1828 by the Swedish chemist Jons Jakob Berzelius, who named it after Thor, the Norse god of war.
Also, all of the mined thorium is potentially useable in a reactor, compared with the 0.7% of natural uranium, so some 40 times the amount of energy per unit mass might be available.
Almost 25 tonnes of thorium was used in fuel for the reactor, and this achieved 170,000 MWd/t burn-up.
www.world-nuclear.org /info/inf62.htm   (2573 words)

  
 C&EN: IT'S ELEMENTAL: THE PERIODIC TABLE - THORIUM
Thorium oxide is used as a catalyst in the production of sulf uric acid and the conversion of ammonia to nitric acid.
Thorium oxide has the highest melting point of all oxides, which can provide a safety benefit as a nuclear reactor fuel.
Thorium is estimated to be three times as abundant as uranium, holding more untapped energy than all oil, coal, natural gas, and uranium combined, with vast reserves in the U.S., Australia, India, Canada, and many other countries.
pubs.acs.org /cen/80th/print/thoriumprint.html   (796 words)

  
 Scientist urges switch to thorium. 14/04/2006. ABC News Online
Thorium oxide, which is three times more abundant than uranium, is also a radioactive material.
Unlike uranium, thorium is not fissile, meaning it must be coaxed into a chain reaction.
At present, there are two methods of achieving this: a mixed fuel thorium reactor, which uses a small amount of uranium to kick-start the nuclear reaction; and then there is the project that Dr Hashemi-Nezhad is working on.
www.abc.net.au /news/newsitems/200604/s1616391.htm   (527 words)

  
 Resource Investor - Rare Earth Metals - Thorium: An Alternative to Uranium   (Site not responding. Last check: )
Thorium was, in fact, tested for this purpose at the very beginning of the design of nuclear power plants for generating electricity for powering submarines.
Thorium’s backers make a compelling case for a running ‘switch’ from uranium based fuel to thorium based fuel in existing Russian reactors and in the construction of new reactors with a mainly thorium based fuel in place of uranium.
Thorium can be blended with weapons-grade plutonium to make fuel for nuclear reactors that convert the plutonium to a grade not suitable for the manufacture of fission weapons.
www.resourceinvestor.com /pebble.asp?relid=16813   (1307 words)

  
 90 Thorium
Thorium also has a number of fairly common application which mean that, unlike uranium, you can actually buy some fairly easily, though not in pure form.
Anti-proliferation thorium breeders use uranium enriched to about 20% (i.e., not enough to use in a uranium bomb) mixed in with a majority of thorium.
For a while thorium was added to lens glass to increase its index of refraction (which allows the lens to be thinner and lighter).
www.theodoregray.com /PeriodicTable/Elements/090   (1833 words)

  
 Thorium (Th) - Chemical properties, Health and Environmental effects
Thorium oxide has a melting point of 3300°C, the highest of all oxides.
The amounts of thorium in the environment may be incidentally increased due to accidental releases of thorium processing plants.
Breathing in thorium in the workplace may increase the chances of development of lung diseases and lung and pancreas cancer many years after people have been exposed.
www.lenntech.com /Periodic-chart-elements/Th-en.htm   (666 words)

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