page_title: Tellurium
section_title: Production
hierarchical_section_title: Tellurium / Production
context_page_description: Tellurium is a chemical element with the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in native form as elemental crystals. Tellurium is far more common in the Universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth, and partly to tellurium's low affinity for oxygen, which causes it to bind preferentially to other chalcophiles in dense minerals that sink into the core.
  Tellurium-bearing compounds were first discovered in 1782 in a gold mine in Kleinschlatten, Transylvania by Austrian mineralogist Franz-Joseph Müller von Reichenstein, although it was Martin Heinrich Klaproth who named the new element in 1798 after the Latin word for "earth", tellus. Gold telluride minerals are the most notable natural gold compounds.
context_section_description: The principal source of tellurium is from anode sludges from the electrolytic refining of blister copper. It is a component of dusts from blast furnace refining of lead. Treatment of 1000 tons of copper ore typically yields one kilogram (2.2 pounds) of tellurium. 
  The anode sludges contain the selenides and tellurides of the noble metals in compounds with the formula M₂Se or M₂Te (M = Cu, Ag, Au). At temperatures of 500 °C the anode sludges are roasted with sodium carbonate under air. The metal ions are reduced to the metals, while the telluride is converted to sodium tellurite.
  M₂Te + O₂ + Na₂CO₃ → Na₂TeO₃ + 2 M + CO₂
  Tellurites can be leached from the mixture with water and are normally present as hydrotellurites HTeO₃⁻ in solution. Selenites are also formed during this process, but they can be separated by adding sulfuric acid. The hydrotellurites are converted into the insoluble tellurium dioxide while the selenites stay in solution.
  HTeO⁻
  ₃ + OH⁻ + H₂SO₄ → TeO₂ + SO²⁻
  ₄ + 2 H₂O
  The metal is produced from the oxide (reduced) either by electrolysis or by reacting the tellurium dioxide with sulfur dioxide in sulfuric acid.
  TeO₂ + 2 SO₂ + 2H₂O → Te + 2 SO²⁻
  ₄ + 4 H⁺
  Commercial-grade tellurium is usually marketed as 200-mesh powder but is also available as slabs, ingots, sticks, or lumps. The year-end price for tellurium in 2000 was US$14 per pound. In recent years, the tellurium price was driven up by increased demand and limited supply, reaching as high as US$100 per pound in 2006. Despite the expectation that improved production methods will double production, the United States Department of Energy (DoE) anticipates a supply shortfall of tellurium by 2025.
  Tellurium is produced mainly in the United States, Peru, Japan and Canada. The British Geological Survey gives the following production numbers for 2009: United States 50 t, Peru 7 t, Japan 40 t and Canada 16 t.
caption: Tellurium production 2006