[network_language_chooser]
Occurrence
Indium is mainly a by-product of the processing of zinc and lead ore. Global supply therefore depends heavily on how much zinc or lead can be mined and how much indium can be refined. Global refinery production is around tons per year. China accounts for by far the largest share of this, with around 70% of global production. Other important producers include South Korea, Japan, Canada and some European countries.
Due to its limited availability and close link to zinc production, indium is considered a strategically relevant technology metal. It plays a central role in modern electronics and communication technology in particular.
Extraction
The extraction of indium is a multi-stage process. The metal usually only occurs in very low concentrations in nature and is mainly a by-product of the processing of zinc and lead. The starting point is therefore residues and intermediate products from zinc smelters, in particular sludges and dusts produced during the processing of zinc sulphide ores. These materials are first chemically treated, often by dissolving them in acids, which causes indium to dissolve together with other metals.
In the next step, the metal is separated from accompanying elements. Various metallurgical processes are used for this, such as solvent extraction, ion exchange or cementation. In this way, indium is separated from metals such as zinc, iron or copper. This is followed by further purification steps in which indium is often initially precipitated as hydroxide or as another compound. Subsequent reduction and further refining steps finally produce metallic indium with a high degree of purity.
The extracted metal is then melted down and processed into ingots or wire. Particularly high degrees of purity are required for applications in electronics or optical coatings, which is why the material often undergoes additional refining steps. Only then can it be used for alloys, semiconductor materials or transparent and conductive coatings, for example.
The global demand for germanium is increasing. In view of the high concentration of extraction and further processing, recycling is becoming increasingly important as a source of this raw material. This also applies to the processing of scrap from the production of germanium-containing products. In Europe, the Critical Raw Materials Act stipulates that 25 percent of the demand for strategic raw materials must be obtained through recycling by 2030. Germanium is one of these materials. Alongside others, the raw materials trader TRADIUM is already working at national and international level to exploit the potential of this raw material source.
