page_title: Zinc
section_title: Mining and processing
hierarchical_section_title: Zinc / Production / Mining and processing
caption_attribution_description: Deutsch: Zink Mine Rosh Pinah English: Zinc Mine Rosh Pinah
context_page_description: Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a blue-silvery appearance when oxidation is removed. It is the first element in group 12 of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state, and the Zn²⁺ and Mg²⁺ ions are of similar size. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite, a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity.
  Brass, an alloy of copper and zinc in various proportions, was used as early as the third millennium BC in the Aegean, Iraq, the United Arab Emirates, Kalmykia, Turkmenistan and Georgia, and the second millennium BC in West India, Uzbekistan, Iran, Syria, Iraq, and Israel/Palestine. Zinc metal was not produced on a large scale until the 12th century in India, though it was known to the ancient Romans and Greeks.
context_section_description: Zinc is the fourth most common metal in use, trailing only iron, aluminium, and copper with an annual production of about 13 million tonnes. The world's largest zinc producer is Nyrstar, a merger of the Australian OZ Minerals and the Belgian Umicore. About 70% of the world's zinc originates from mining, while the remaining 30% comes from recycling secondary zinc. Commercially pure zinc is known as Special High Grade, often abbreviated SHG, and is 99.995% pure.
  Worldwide, 95% of new zinc is mined from sulfidic ore deposits, in which sphalerite (ZnS) is nearly always mixed with the sulfides of copper, lead and iron. Zinc mines are scattered throughout the world, with the main areas being China, Australia, and Peru. China produced 38% of the global zinc output in 2014.
  Zinc metal is produced using extractive metallurgy. The ore is finely ground, then put through froth flotation to separate minerals from gangue (on the property of hydrophobicity), to get a zinc sulfide ore concentrate consisting of about 50% zinc, 32% sulfur, 13% iron, and 5% SiO
  ₂.
  Roasting converts the zinc sulfide concentrate to zinc oxide:
  2 ZnS + 3 O
  ₂ → 2 ZnO + 2 SO
  ₂
  The sulfur dioxide is used for the production of sulfuric acid, which is necessary for the leaching process. If deposits of zinc carbonate, zinc silicate, or zinc spinel (like the Skorpion Deposit in Namibia) are used for zinc production, the roasting can be omitted.
  For further processing two basic methods are used: pyrometallurgy or electrowinning. Pyrometallurgy reduces zinc oxide with carbon or carbon monoxide at 950 °C (1,740 °F) into the metal, which is distilled as zinc vapor to separate it from other metals, which are not volatile at those temperatures. The zinc vapor is collected in a condenser. The equations below describe this process:
  2 ZnO + C → 2 Zn + CO
  ₂
  ZnO + CO → Zn + CO
  ₂
  In electrowinning, zinc is leached from the ore concentrate by sulfuric acid:
  ZnO + H
  ₂SO
  ₄ → ZnSO
  ₄ + H
  ₂O
  Finally, the zinc is reduced by electrolysis.
  2 ZnSO
  ₄ + 2 H
  ₂O → 2 Zn + 2 H
  ₂SO
  ₄ + O
  ₂
  The sulfuric acid is regenerated and recycled to the leaching step.
  When galvanised feedstock is fed to an electric arc furnace, the zinc is recovered from the dust by a number of processes, predominantly the Waelz process (90% as of 2014).
caption: Zinc Mine Rosh Pinah, Namibia
  27°57′17″S 016°46′00″E﻿ / ﻿27.95472°S 16.76667°E﻿ / -27.95472; 16.76667﻿ (Rosh Pinah)
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