ingredient information
Erbium
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Erbium (pronounced /'?rbi?m/) is a chemical element with the symbol Er and atomic number 68. A rare, silvery, white metallic lanthanide, erbium is solid in its normal state. It is a rare earth element associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden. Crushed minerals are attacked by hydrochloric or sulfuric acid that transforms insoluble rare-earth oxides into soluble chlorides or sulfates. The acidic filtrates are partially neutralized with caustic soda to pH 3-4. Thorium precipitates out of solution as hydroxide and is removed. After that the solution is treated with ammonium oxalate to convert rare earths in to their insoluble oxalates. The oxalates are converted to oxides by annealing. The oxides are dissolved in nitric acid that excludes one of the main components, cerium, whose oxide is insoluble in HNO3. The solution is treated with magnesium nitrate to produce a crystallized mixture of double salts of rare-earth metals. The salts are separated by ion exchange. In this process, rare-earth ions are sorbed onto suitable ion-exchange resin by exchange with hydrogen, ammonium or cupric ions present in the resin. The rare earth ions are then selectively washed out by suitable complexing agent.[7] Erbium metal is obtained from its oxide or salts by heating with calcium at 1450 °C under argon atmosphere