Erbium REE Collection rare earth metals elements

Erbium

It is likely that when Mosander discovered two new rare-earth elements in the same experiment he said “I just want to celebrate.” Pretty in pink was the terbium oxide precipitate while the other oxide, erbium, was a mellow yellow. Somehow the names of the two elements were switched and by the time it was officially named, erbium became the element “in the pink.” After discovering lanthanum four years earlier, Mosander’s colorful chemistry career climaxed with these two discoveries, giving him the rare earth “hat trick” or “trivalent triple play.”

Applications

  • Erbium:yttrium aluminum garnet (Er:YAG) lasers are used in dermatology for skin resurfacing to remove wrinkles.
  • In sunglasses, erbium oxide enhances color perception and improves both contrast and depth perception.
  • Added to cubic zirconia jewelry, decorative glass, and ceramic glazes, erbium oxide produces a delicate light pink colour.
  • Erbium oxide is a fiber optic amplifier that allows the light signal to travel great distances without externally boosting the signal. (fiber optic light photo)
  • In recycling, Erbium and zinc oxides are added to brown glass making it almost colorless.

Interesting Facts

  • The “pink ice” cubic zirconia is colored by erbium oxide.
  • Harry Potter’s Daniel Radcliffe sings Ton Lehrer’s the periodic table song including the line “There's holmium and helium and hafnium and erbium.”
  • Nuclear control rods in pressurized water reactors (PWR) use erbium alloys to control the fission process by absorbing thermal neutrons.

Discovery

In 1843, Swedish chemist and pharmacist Carl Gustav Mosander separated from an impure yttria the known rare-earth elements ceria, lanthana, and didymia, and was left with three oxides, one white, one yellow, and one pink (Mosander, 1843). The white oxide was the previously discovered element yttria, however, the yellow and pink oxides were two new rare earths, which he named, and sent forth to the foremost analytical chemists of the time for confirmation. For the new elements, Mosander named the yellow earth erbia and the pink element terbia. By the time they all came back, the names of the elements were somehow interchanged from their original descriptions and erbium, the name of the yellow colored oxide, became the pink colored oxide (Weeks and Leicester, 1968, p. 677). Erbium is named for the small village and mine location in Sweden where the original rare-earth yttrium-bearing mineral was discovered, Ytterby.

Definition

Erbium is a bright silvery metal that is fairly stable in air. The metal is soft and malleable. Erbium metal has a high electrical resistivity. It has a hexagonal close-packed structure, a density of 9.066 gm/cm3, a melting point of 1529 °C, and a boiling point of 2870 °C. Erbium oxide, or yttria, occurs as a sesquioxide with the formula Er2O3. The oxide is a pink powder with a melting point of 2400 °C, a specific gravity of 8.6 gm/cm3 and a formula weight of 382.56. Erbium has six naturally-occurring isotopes and nine radioactive isotopes.

Preparation of Metal

Erbium metal is typically prepared by calciothermic reduction of the trihalide, typically ErF3. Although its melting point is similar to Y, Gd, Tb, and Lu, its vapor pressure at the melting point is much higher. This makes purification of Er, and similar elements Sc, Ho, and Dy with high vapor pressures, comparatively easy. Common interstitial impurities which form stable compounds with nitrogen, carbon, and oxygen remain in the residue when the metal is sublimed at 1300 °C at a slow rate (Beaudry and Gschneidner, Jr., 1978). Erbium metal is formed when the fluoride preferentially separates from erbium fluoride at high-temperature and combines with calcium metal forming calcium fluoride and deposits a high-purity erbium metal.

Source

Large resources of erbium in xenotime and monazite are available worldwide in ancient and recent placer deposits, uranium ores, and weathered clay deposits (ion-adsorption ore). It occurs in the Earth’s crust at an average concentration of 3 parts per million. Xenotime is enriched in erbium oxide and contains 5.6% to 6.4% of the rare-earth oxide (REO) content. Monazite-(Ce), which is more abundant in the Earth’s’ crust than xenotime, has erbium oxide contents ranging from trace amounts to a more typical 0.1% to 0.2% of the REO content. The yttrium-enriched Longnan-type ion-adsorption ore has erbium oxide content of about 6.7% of the REO total, however, the Xunwu-type contains 0.88%. Erbium oxide only occurs in trace amounts in the bastnäsites at the Bayan Obo mine in China and at Mountain Pass, California, in the United States. Hard rock monazite-(Nd) in the Lemhi Pass district of Idaho-Montana has an average erbium oxide content of 0.43% of the REO distribution (Hedrick, unpublished manuscript). Subeconomic resources of erbium occur in apatite-magnetite-bearing rocks, eudialyte-bearing deposits, deposits of niobium-tantalum minerals, non-placer monazite-bearing deposits, sedimentary phosphate deposits, and uranium ores, especially those of the Blind River District near Elliot Lake, Ontario, Canada, which contain dysprosium in brannerite, monazite, and uraninite. Additional subeconomic resources in Canada are contained in allanite, apatite, and britholite at Eden Lake, Manitoba; allanite and apatite at Hoidas Lake, Saskatchewan; fergusonite and xenotime at Nechalacho (Thor Lake), Northwest Territories; and eudialyte-(Y), mosandrite, and britholite at Kipawa, Quebec. It occurs in various minerals in differing concentrations and occurs in a wide variety of geologic environments, including alkaline granites and intrusives, carbonatites, hydrothermal deposits, laterites, placers, and vein-type deposits (Hedrick, 2010).

Mining

Erbium is mined from a variety of ore minerals and deposits using various methods. Monazite and xenotime are 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 (Hedrick, 1991). Vein monazite has been mined by hard-rock methods in South Africa and the United States, and as a byproduct of tungsten mining in China (Hedrick, 2010).

In Russia, 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 with a 0.8% Er2O3 content. In Kyrgyzstan, synchysite-(Y) with a Er2O3 content of 3.8% was mined by hard-rock methods from the open-pit Kutessai-II deposit near Aktyuz (Hedrick, Sinha, and Kosynkin, 1997). Argillaceous marine sediments enriched in fossil fish remains at the Melovie deposit in Kazakhstan were previously recovered for their uranium and rare-earth content, including erbium. The main source of the world’s erbium is the ion-adsorption lateritic clays in the southern provinces of China, primarily Fujian, Guangdong, and Jiangxi, with a lesser number of deposits in Guangxi and Hunan. These deposits are mined by leaching methods (Hedrick, 2010).

Selected erbium-bearing minerals

Gadolinite-(Y) Y2Fe2+Be2(Si2O10)
Monazite (Ce,La,Nd,Th)(PO4)
Xenotime Y(PO4)
Synchysite-(Y) Ca(Y,Ce)(CO3)2F
Loparite-(Ce) (Ce,Na,Ca,Sr,Th)(Ti,Nb,Ta,Fe+3)O3
Euxenite-(Y) (Y,Ca,Ce,U,Th)(Nb,Ti,Ta)2O6
Eudialyte-(Y) Na4(Ca,Ce)2(Fe2+,Mn,Y)ZrSi8O22(OH,Cl)2
Cerite-(Ce) (Ca,Ce)9(Fe,Mg)(SiO4)3(HSiO4)(OH)3
Mosandrite Na2Ca4(REE)(Si2O7)2OF3
Britholite-(Y) Ca2(Y,Ca)3(SiO4,PO4)3(OH,F)
Iimoriite-(Y) Y2(SiO4)(CO3)
Allanite-(Y) (Ca,Ce)(Al2,Fe+2)(Si2O7)(SiO4)O(OH) Ion adsorption lateritic clays Y-enriched lateritic clays
Ion adsorption lateritic clays Y-enriched lateritic clays
Brannerite (U4+,REE,Th,Ca)(Ti,Fe3+,Nb)2(O,OH)6

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.

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., 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.

Hedrick, James B., 2010, Yttrium: chapter in Mineral commodity summaries 2010, U.S. Geological Survey, p. 182-183.

Hedrick, James B., Shyama P. Sinha, and Valery D. Kosynkin, 1997, Loparite—a rare-earth ore (Ce,Na,Sr,Ca)(Ti,Nb,Ta,Fe+3)O3: Journal of Alloys and Compounds, v. 250, p. 467-470.

Mosander, C. G., 1843, On the new metals, Lanthanium and didymium, which are associated with cerium; and on erbium and terbium, new metals associated with yttria: Philosophical Magazine, series 3, v. 23, no. 152, p. 241-254.

Weeks, Mary E., and Henry M. Leicester, 1968, Discovery of the Elements (7th ed.): Easton, Pennsylvania, Journal of Chemical Education, 896 p.

Electrons per shell:
2, 8, 18, 30, 8, 2
Atomic number,
Protons, Electrons:
68
Number of Neutrons:
99
Atomic Mass:
167.26 amu
Melting Point:
1529.0 °C
Boiling Point:
2870.0 °C
Density @ 293 K:
9.066 g/cm3
Crystal structure:
hexagonal
Color:
grayish