Cell phones to feed algae

Scientists at the Perm Polytechnic University have learned how to extract a rare metal from used phones

Perm scientists have learned to reuse spent phones. More precisely, we are talking about a rare metal indium, which is used to make computer monitors and touch screens.

Indium is a rare metal that does not have its own deposits. It is mined in the mining of other metals. Experts predict that its reserves may run out in the coming decades. Given this, scientists are thinking about what could replace this element. And specialists from Perm came from the other side – they offered to re-extract it from … telephones and LCD computer monitors.

To extract the metal, scientists crushed the screens of mobile phones, smartphones and monitors in a ball mill. After leaching with sulfuric acid, indium ions were extracted from the resulting solution. The dried biomass of microscopic algae of the genus Chlorella helped the researchers from the Polytechnic University in this. Their dehydrated cells, due to the porous structure of the cell membrane, are able to passively absorb elements. At the last stage, the algae are simply burned, after which only indium remains. This method turned out to be also environmentally friendly – it does not lead to the formation of toxic substances.

The resulting metal, by the way, can be used not only in phone screens.

In an alloy with silver, indium oxide is used to produce astronomical mirrors and car headlight mirrors.