Germanium

Germanium is an essentially non‐toxic element, except for a few compounds. Germanium is a rare element in rocks. However, it is present in trace quantities in most rock types because of its siderophile, lithophile, chalcophile and organophile characters. Germanium is a trace metal in most types of oxidic and sulfidic metalliferous deposits, including banded iron formations, manganese nodules, shale‐hosted sedimentary copper deposits and porphyry copper deposits. Germanium is a by‐product in some sulfide ores and in some coals; therefore, surface and underground mining methods that are commonly used to extract base metals and coal are employed. After mining, the ores are processed to increase their base metal and germanium contents using conventional mechanical and flotation methods. Future germanium supplies will continue to depend upon the availability of germanium‐bearing residues from the processing of zinc ores, from germanium‐bearing coal ash and from recycling.