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Rare Earth Element
The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. Compounds containing rare earths have diverse applications in electrical and electronic components, lasers, glass, magnetic materials, and industrial processes. The term "rare-earth" is a misnomer because they are not actually scarce, but historically it took a long time to isolate these elements. They are relatively plentiful in the entire Earth's crust ( cerium being the 25th-most-abundant element at 68 parts per million, more abundant than copper), but in practice they are spread thinly as trace impurities, so to obtain rare earths at usable purity requires processing enormous amounts of raw ore at great expense; thus the name "rare" earths. Scandium and yttrium a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rare-earth Mineral
A rare-earth mineral contains one or more rare-earth elements as major metal constituents. Rare-earth minerals are usually found in association with alkaline to peralkaline igneous magmas in pegmatites or with carbonatite Intrusive rock, intrusives. Perovskite (structure), Perovskite mineral phases are common hosts to rare-earth elements within the alkaline complexes. Minerals are solids composed of various inorganic elements, mixed through processes such as evaporation, pressure or other physical changes. Rare earth minerals are rare because rare earth elements have unique geochemical properties that prevent them from easily forming minerals, and are therefore not normally found in deposits large or concentrated enough for mining. This is the reason they are called "rare" earths. These elements have a wide range of uses from every day items to military technologies. The minerals that do exist are often associated with alkaline magmas or with carbonatite Intrusive rock, intrusive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Properties
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, magnetism is one of two aspects of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only a few substances are ferromagnetic; the most common ones are iron, cobalt, nickel, and their alloys. All substances exhibit some type of magnetism. Magnetic materials are classified according to their bulk susceptibility. Ferromagnetism is responsible for most of the effects of magnetism encountered in everyday life, but there are actually several types of magnetism. Paramagnetic substances, such as aluminium and oxygen, are weakly attracted to an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweden
Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic country by both area and population, and is the List of European countries by area, fifth-largest country in Europe. Its capital and largest city is Stockholm. Sweden has a population of 10.6 million, and a low population density of ; 88% of Swedes reside in urban areas. They are mostly in the central and southern half of the country. Sweden's urban areas together cover 1.5% of its land area. Sweden has a diverse Climate of Sweden, climate owing to the length of the country, which ranges from 55th parallel north, 55°N to 69th parallel north, 69°N. Sweden has been inhabited since Prehistoric Sweden, prehistoric times around 12,000 BC. The inhabitants emerged as the Geats () and Swedes (tribe), Swedes (), who formed part of the sea-faring peopl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ytterby
Ytterby () is a village on the Swedish island of Resarö, in Vaxholm Municipality in the Stockholm archipelago. Today the residential area is dominated by suburban homes. The name of the village translates to "outer village". Ytterby is the single richest source of elemental discoveries in the world; the chemical elements yttrium (Y), terbium (Tb), erbium (Er), and ytterbium (Yb) are all named after Ytterby, and the elements holmium (Ho), scandium (Sc), thulium (Tm), tantalum (Ta), and gadolinium (Gd) were also first discovered there. Local roads connect Ytterby to and hence the mainland. Except for the winter months, passenger ships of the '' Waxholmsbolaget'' call at a pier in Ytterby, providing a connection to Vaxholm town and Stockholm. Mine Quartz was mined in the area beginning in the 1600s for the ironworks in Uppland. Feldspar was mined for local porcelain manufacture, such as Gustavsberg, and the porcelain trade with Britain and Poland. The mine is likely the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gadolinite
Gadolinite, sometimes known as ytterbite, is a silicate mineral consisting principally of the silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron with the formula . It is called gadolinite-(Ce) or gadolinite-(Y), depending on the prominent composing element (Y if yttrium predominates, and Ce if cerium). It may contain 35.5% yttria sub-group rare earths, 2.2% ceria earths, as much as to 11.6% BeO, and traces of thorium. It is found in Sweden, Norway, and the US (Texas and Colorado). Characteristics Gadolinite is fairly rare and typically occurs as well-formed crystals. It is nearly black in color and has a vitreous luster. The hardness is between 6.5 and 7 on the Mohs scale, and the specific gravity is between 4.0 and 4.7. It fractures in a conchoidal pattern and streaks grayish-green. It was also thought to exhibit pyrognomic properties, as it can emit visible light when heated to relatively low temperatures, but the scientific consensus is that this is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precious Metals
Precious metals are rare, naturally occurring metallic chemical elements of high economic value. Precious metals, particularly the noble metals, are more corrosion resistant and less chemically reactive than most elements. They are usually ductile and have a high lustre. Historically, precious metals were important as currency but they are now regarded mainly as investment and industrial raw materials. Gold, silver, platinum, and palladium each have an ISO 4217 currency code. The best known precious metals are the precious coinage metals, which are gold and silver. Although both have industrial uses, they are better known for their uses in art, jewelry, and coinage. Other precious metals include the platinum group metals: ruthenium, rhodium, palladium, osmium, iridium, and platinum, of which platinum is the most widely traded. The demand for precious metals is driven not only by their practical use but also by their role as investments and a store of value. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rare-earth Mineral
A rare-earth mineral contains one or more rare-earth elements as major metal constituents. Rare-earth minerals are usually found in association with alkaline to peralkaline igneous magmas in pegmatites or with carbonatite Intrusive rock, intrusives. Perovskite (structure), Perovskite mineral phases are common hosts to rare-earth elements within the alkaline complexes. Minerals are solids composed of various inorganic elements, mixed through processes such as evaporation, pressure or other physical changes. Rare earth minerals are rare because rare earth elements have unique geochemical properties that prevent them from easily forming minerals, and are therefore not normally found in deposits large or concentrated enough for mining. This is the reason they are called "rare" earths. These elements have a wide range of uses from every day items to military technologies. The minerals that do exist are often associated with alkaline magmas or with carbonatite Intrusive rock, intrusive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geochemical
Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the entire Solar System, and has made important contributions to the understanding of a number of processes including mantle convection, the formation of planets and the origins of granite and basalt. It is an integrated field of chemistry and geology. History The term ''geochemistry'' was first used by the Swiss-German chemist Christian Friedrich Schönbein in 1838: "a comparative geochemistry ought to be launched, before geognosy can become geology, and before the mystery of the genesis of our planets and their inorganic matter may be revealed." However, for the rest of the century the more common term was "chemical geology", and there was little contact between geologists and chemists. Geochemistry emerged as a separate discipline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium
Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactive decay, radioactively decays, usually by emitting an alpha particle. The half-life of this decay varies between 159,200 and 4.5 billion years for different isotopes of uranium, isotopes, making them useful for dating the age of the Earth. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordial nuclide, primordially occurring elements. Its density is about 70% higher than that of lead and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few Parts-per notation#Parts-per expressions, parts per million in soil, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorium
Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided. All known thorium isotopes are unstable. The most stable isotope, 232Th, has a half-life of 14.05 billion years, or about the age of the universe; it decays very slowly via alpha decay, starting a decay chain named the thorium series that ends at stable 208 Pb. On Earth, thorium and uranium are the only elements with no stable or nearly-stable isotopes that still occur naturally in large quantities as primordial elements. Thorium is estimated to be over three times as abundant as uranium in the Earth's crust, and is chiefly refined from monazite sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Minerals'; p. 1. In the series ''Geology: Landforms, Minerals, and Rocks''. Rosen Publishing Group. The Geology, geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks. The concept of mineral is distinct from rock (geology), rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral or may be an aggregate (geology), aggregate of two or more different types of minerals, spaci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium-238
Uranium-238 ( or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it is fissionable by fast neutrons, and is ''fertile'', meaning it can be transmuted to fissile plutonium-239. 238U cannot support a chain reaction because inelastic scattering reduces neutron energy below the range where fast fission of one or more next-generation nuclei is probable. Doppler broadening of 238U's neutron absorption resonances, increasing absorption as fuel temperature increases, is also an essential negative feedback mechanism for reactor control. Around 99.284% of natural uranium's mass is uranium-238, which has a half-life of 1.41 seconds (4.468 years, or 4.468 billion years). Due to its natural abundance and half-life relative to other radioactive elements, 238U produces ~40% of the radioactive heat produced wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
