Questo post è disponibile anche in: Italian
The University of Edinburgh discovered a way to retrieve the precious metal from electronic devices without using toxic substances.
To all gold miners of the world: the mine of the future won’t be in the Wild West nor in Klondike, but rather in your pockets. The precious metal contained in the electronic circuits of devices of all sizes – and above all in smartphones – makes up for about 7% of all the gold on Planet Earth.
The problem is that the current method to extract the shiny metal from old smartphones is not efficient enough and is also rather dangerous, as it requires the usage of toxic chemicals.
Now, though, a team of Edinburgh scientists has developed a simple extraction method that does not use toxic chemicals and recovers gold more effectively than current methods. According to the researchers’ estimates, the finding could help salvage some of the estimated 300 tons of gold used in electronics each year. The operation is simple. The printed circuit boards are first placed in an acid that dissolves all of their metal parts. An oily toluene solvent containing the team’s primary amide is then added: this allows to extract gold selectively from the mixture of other metals.
“After separation of the oily phase from the acid phase, washing the oily phase with water transfers the gold into the water phase for electrowinning – says Jason Love, from Edinburgh University’s School of Chemistry – We have to do this a couple of times to ensure complete phase transfer, but each wash step is very quick.”
So far, researchers managed to extract 85% of gold contained in old circuit boards. The project could also aid the development of methods for industrial scale recovery of gold and other precious metals from waste electronics. “We want to look into developing a whole process to satisfy a possible circular economy theme” concluded Prof Love.
Source: The Engineer