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How germanium is recovered

Zone refining can purify germanium to one impurity atom in ten billion.

stations
5
things upstream
10
raw sources
6
steps from the ground
4

The short version

Germanium is a by-product of zinc smelting, recovered from sphalerite where it concentrates at up to 0.3 percent, and from coal fly ash in some countries. Zinc concentrate is roasted and leached with acid, germanium precipitates out, and it is converted to a volatile chloride for purification. Zone refining then gives semiconductor grade.

  1. Roast the ore concentrate

    Sulfide concentrates are heated in air to turn them into oxides. Some germanium stays in the dust and some becomes germanates.

    Goes in
    Zinc ore

  2. Leach with sulfuric acid

    Acid dissolves zinc and germanates from the cinder. After neutralization the zinc stays dissolved while germanium and other metals drop out.

    Goes in
    Sulfuric acid

  3. Concentrate the oxide

    The precipitate goes through the Waelz process to remove part of the zinc, and a second leach brings out germanium dioxide.

  4. Convert to a liquid chloride

    The dioxide reacts with hydrochloric acid or chlorine to make germanium tetrachloride, a fuming liquid that boils at 83.1 °C and can be distilled clean.

    Goes in
    Hydrochloric acid

  5. Zone refine the metal

    The purified chloride is turned back into oxide and reduced to metal with hydrogen. Zone refining then sweeps a narrow molten band along a bar, and impurities end up at one end.

    Goes in
    Hydrogen
End of the lineGermanium Next it goes into optical fiber.

Worth repeating

  • Clemens Winkler found germanium in a silver mineral in 1886, filling a gap Mendeleev had predicted.
  • The first decade of semiconductor electronics was based entirely on germanium.

Back to the ground

Follow every input upstream and germanium starts as these 6 raw sources.

Zinc oreSulfurAirWaterNatural gasRock salt

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Where it comes from

  1. China80 tonnes
  2. Russia5 tonnes
  3. United States3 tonnes

2011 world output of about 118 tonnes (Wikipedia).

Where it goes next

Germanium feeds 1 line directly.

Optical fiber

Keep walking

Ethylene glycol 6 stations · 8 raw sources Naphtha 5 stations · 3 raw sources Natural gas 4 stations Acetone 5 stations · 5 raw sources Baking soda 6 stations · 9 raw sources Asphalt 5 stations · 2 raw sources

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Sources

Cite this page: "How germanium is recovered." Assembly Line, 2026-11-03. https://assemblyline.org/make/germanium

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