Indium

Indium is a very soft, silvery-white, highly ductile, relatively rare post-transition metal It is very soft (Mohs hardness 1.2). Indium has a low melting point: 156.60°C.

Indium is used in electronic applications as:

• ITO (Indium Tin Oxide) conductive layer for flat displays,
• Alloys with gallium, with antimony, with phosphor and with nitrogen for semi conductors,
• Combined compounds for CIS (Copper, Indium, Selenium) solar cells,

It is also used as solder or conductive adhesive.

Indium is produced as by-product from Zn, Cu, Sn and other polymetallic elements minerals. It is rarely found as rich deposit and therefore difficult and costly to extract.

Even if indium is more abundant than silver, concerns exist on its long term availability. It is the reason why recycling will become important. Indeed, it is considered that only 1% of the used indium is recycled.

ELSA developed a process to recuperate Indium and Tin from ITO coated glass panels.

The process comprises:

• A lixiviation step where In is solubilised,
• A cementation step on Zinc for In recovery.

The zinc in solution was then recycled by electrolysis. 

• Development program with a Japanese company.