Samarium
Applications
- High-strength samarium cobalt magnets allowed the miniaturization of hundreds of applications in the 1970s including cassette tape players, computer disk drives, headphones, boom boxes, and speakers.
- Fender manufacturers single coil noiseless (no background hum) guitar pickups using samarium cobalt magnets.
- Samarium X-ray lasers have applications in radiography.
- Samarium-cobalt permanent magnets are used in many defense applications including servo-motors to adjust the flight control surfaces (fins) on missiles.
Interesting Facts
- Based on samarium cobalt magnets, Sony introduced the TPS-L2 Walkman, the first portable audio cassette player in 1979, beginning the era of personal music listening which evolved into DVD players and then MP3 players.
- The samarium isotope, Sm-153, is used to treat rheumatoid arthritis of the knee and other joints. The isotope's beta emissions penetrate the synovium (soft tissue) of the joints to about 2.5 millimeters and have a short half-life.
- Samarium was the first element to be named after a person.
- Samarium chloride taken internally in the proper quantity will combine with alcohol and keep you from becoming drunk.
Discovery
Samarium was discovered by French chemist Paul Émile Lecoq de Boisbaudran in 1879.
He noticed in his research that impure didymium (praseodymium and neodymium with other impurities), seemed to contain more than just didymium based on spectroscopic work on various rare-earth minerals.
When Lecoq de Boisbaudran added ammonium hydroxide to a concentrate prepared from the mineral samarskite he observed a precipitate that formed before the didymium (Weeks and Leicester, 1968, p. 685).
The new earth that precipitated had a unique spectrum and de Boisbaudran named it samaria, after the mineral from which it was derived (Lecoq de Boisbraudran, 1879).
The mineral samarskite is named for a Russian mining engineer and Chief of Staff - Corps of Mining Engineers, Colonel Vasili Evgrafovich Samarsky-Bykhovets.
The mineral was discovered and renamed by German mineralogist Heinrich Rose who determined it contained primarily niobium, and changed the name from uranotantalum to samarskite to avoid confusion (Rose, 1847).
He named the mineral in honor of V.E. Samarsky-Bykjovets for granting access to mineral samples.
The samarskite was from the Blyumovskaya Pit, Ilmen Mountains, Southern Urals, Russia.
Definition
Samarium is a silvery-yellow lustrous metal that tarnishes in air. Samarium will ignite in air at about 150 °C. The metal is relatively hard and brittle. It has a rhombohedra structure, a density of 7.536 gm/cm3, a melting point of 1072 °C, and a boiling point of 1900 °C. Samarium oxide, or samaria, occurs as a sesquioxide with the formula Sm2O3. The trivalent oxide is a light-yellowish powder with a specific gravity of 7.1 gm/cm3 and a formula weight of 348.70. The bivalent oxide is red-brown. Samarium has 16 isotopes. Natural occurring samarium contains 7 isotopes, with 3 being unstable with long half-lives.Preparation of Metal
Samarium metal is typically prepared by metallothermic reduction of the oxide, since it will not reduce from the trihalide because of its high vapor pressure. The oxide is is heated in air to 800 °C for 15 hours to drive off absorbed moisture, carbon dioxide, and other compounds. Samarium oxide is reduced with lanthanum metal turnings (15% in excess of theoretical amount) by volatilization within a tantalum crucible with an attached tantalum condenser. The reactants are heated in a vacuum reduction furnace by slowing raising the temperature to 1600 °C and held at temperature for several hours (Beaudry and Gschneidner, Jr., 1978). Samarium metal is formed starting at 800 °C when the oxide preferentially separates from the samarium oxide and combines with the lanthanum metal forming lanthanum oxide and forms a sublimated samarium metal within the tantalum condenser.Source
Large resources of samarium are contained in LREE-enriched minerals. Samarium occurs in the Earth's crust at an average concentration of 6 parts per million. The primary source of samarium is from carbonatites and the LREE-mineral bastnäsite. Bastnäsite deposits in China and the United States constitute the largest percentage of the world's rare-earth economic resources. Samarium is also a constituent in the LREE-mineral monazite which constitutes the second largest segment of rare-earth resources. Monazite deposits are located in Australia, Brazil, China, India, Malaysia, South Africa, Sri Lanka, Thailand, and the United States in paleoplacer and recent placer deposits, sedimentary deposits, veins, pegmatites, carbonatites, and alkaline complexes (Hedrick, 2010). Samarium sourced from the LREE-mineral loparite is recovered from a large alkali igneous intrusion in Russia (Hedrick, Sinha, and Kosynkin, 1997).Mining
Samarium, a light-group rare-earth element (LREE) is mined from a variety of ore minerals and deposits using various methods. Bastnäsite is mined in the United States as a primary product from a hard-rock carbonatite. The deposit is mined via bench-cut open pit methods. Ore is drilled and blasted, loaded into trucks by loaders, and hauled to the mill. At the mill the blasted ore is crushed, screened, and processed by flotation to produce a bastnäsite concentrate. In China, bastnäsite and lesser amounts of associated monazite are also mined from a carbonatite. The ore is recovered as a byproduct of iron ore mining by hard-rock open pit methods. After crushing the ore is separated from the iron ore by flotation to produce a bastnäsite concentrate and a bastnäsite-monazite concentrate (Hedrick, 1990).Monazite is recovered from heavy-mineral sands (specific gravity >2.9) deposits in various parts of the world as a byproduct of mining zircon and titanium-minerals or tin minerals. Heavy mineral sands are recovered by surface placer methods from unconsolidated sands. Many of these deposits are mined using floating dredges which separate the heavy-mineral sands from the lighter weight fraction with an on-board wet mill through a series of wet-gravity equipment that includes screens, hydrocyclones, spirals, and cone concentrators. Consolidated or partially consolidated sand deposits that are too difficult to mine by dredging are mined by dry methods. Ore is stripped by typical earth-moving equipment with bulldozers, scrapers, and loaders or by water jet methods. Ore recovered by these methods is crushed and screened and then processed by the wet mill described above. Wet mill heavy-mineral concentrate is sent to a dry mill for processing to separate the individual heavy-minerals using a combination of scrubbing, drying, screening, electrostatic, electromagnetic, magnetic, and gravity processes. Vein monazite has been mined by hard-rock methods in South Africa and the United States (Hedrick, 2010). Loparite is mined by underground methods using room and pillar methods. Ore is drilled and blasted and removed from the mine. The ore is then processed by the same hard-rock methods as applied to bastnäsite to make a loparite concentrate.
Selected samarium minerals
| Bastnäsite-(Ce) | (Ce,La,Nd,Pr)(CO3)F |
| Monazite-(Ce) | (Ce,La,Nd,Th)(PO4) |
| Loparite-(Ce) | (Ce,Na,Ca,Sr,Th)(Ti,Nb,Ta,Fe+3)O3 |
| Allanite-(Ce) | (Ca,Ce)(Al2,Fe+2)(Si2O7)(SiO4)O(OH) |
| Parisite-(Ce) | Ca(Ce,La)2(CO3)3F2 |
| Ancylite-(Ce) | SrCe(CO3)2(OH) · H2O |
| Britholite-(Ce) | Ca2(Ca,Ce)3(SiO4,PO4)3(OH,F) |
| Cerite-(Ce) | (Ca,Ce)9(Fe,Mg)(SiO4)3(HSiO4)(OH)3 |
| Samarakite-(Y) | (Y,Fe+3,Fe+3,U,Th,Ca)2(Nb,Ta)2O8 |
References
Beaudry and Bernard J. and Karl A. Gschneidner, Jr., 1978, Preparation and Basic Properties of the Rare Earth Metals: chapter 2 in Handbook of the Physics and Chemistry of Rare Earths-Volume 1:Metals, (Gschneidner, Jr. and Eyring, editors), North-Holland, New York, p. 173-232.Lecoq de Boisbaudran, Pierre E., 1879, Nouvelles raies spectrales observées dans des substances extradites de la samarskite [New spectral lines observed in substances extracted of samarskite]: Comptes Rendus, February 17, v. 88, p. 322-324.
Gschneidner, Karl A. Jr., 2011, The Rare Earth Crisis—The Supply/Demand Situation for 2010-2015: article in Material Matters, Aldrich Chemical Co., Milwaukee, Wisconsin, v. 6, no. 2, p. 34-35.
Hedrick, James B., Rare earth history: unpublished manuscript, 11 p.
Hedrick, James B., 2010, Rare earths: chapter in Mineral commodity summaries 2010, U.S. Geological Survey, p. 128-129.
Hedrick, James B., 1990, Rare earths—The lanthanides, yttrium, and scandium: chapter in Minerals Yearbook 1990, U.S. Geological Survey, v. 1, p. 903-922.
Hedrick, James B., 1991, Rare earths—The lanthanides, yttrium, and scandium: chapter in Minerals Yearbook 1991, U.S. Geological Survey, v. 1, p. 1211-1237.
Горный журнал [Mining Journal], 1847, part II, vol. 4, p. 118. "Я предлагаю изменить название уранотантал в самарскит, в честь полковника Самарского, по благосклонности которого я был в состоянии производить над этим минералом все изложенные наблюдения" [I propose to rename uranotantalum into samarskite, in honor of Colonel Samarsky, on benevolence of whom I was able to conduct my studies of this mineral].
Rose , Heinrich, 1847, Annalen Physik, v. 71, p. 157.
Weeks, Mary E., and Henry M. Leicester, 1968, Discovery of the Elements (7th ed.): Easton, Pennsylvania, Journal of Chemical Education, 896 p.
Protons, Electrons: