Silver solar panels: Scientists find new way to extract the precious metal

Scientists at the University of Leicester have developed a new way of getting silver out of old solar panels.

They say the method, which uses a type of salt water instead of acid, is more environmentally friendly.

The silver can then be reused, either in new solar panels or to make things like microchips and circuit boards which are used in computers.

It's hoped this new method can also be used to recycle silver from other sources like old smartphones and magnets.

Traditionally silver has been used to make jewellery, cutlery and decorative plates and bowls but it also has lots of uses in modern technology like electronics

What is silver used for?

You might think of silver as being a metal mainly used to make jewellery but it has lots of other uses.

One of the main ones is to make photovoltaic (PV) cells, also known as solar cells.

Solar panels are a way of using light from the sun to make electricity.

This is a type of renewable energy but the solar panels themselves only last for around 25-30 years.

With increased demand for green energy the demand for solar panels is expected to increase but that could mean a lot of waste once they have stopped working.

That's why scientists are investigating how to get the silver out of the panels so it can be used again.

Silver is also used in LED chips which are used in lighting

Why do people want to recycle silver?

Silver is a precious metal with lots of different and important industrial uses.

Mining for new silver, which needs to be dug out of the ground as ore (part of rock) and then processed to extract the silver, takes time and money.

There is a limited amount of silver left in the earth so people want to reuse the silver that is already being used.

Choline chloride is used in chicken feed but also in the 'unusual brine' researchers have been using to extract silver in solar cells

How does it work?

The old method of getting silver from solar panels uses mineral acid to dissolve it, but the process is expensive and causes damage the environment.

The new way uses chemicals from chicken feed (choline chloride) and de-icer (calcium chloride) to make a type of salty water called brine.

The scientists behind the study say this makes it a cheaper and more environmentally friendly way of reclaiming the precious metal.

Dr Guillaume Zante, from the Centre for Materials Research at the University of Leicester, said: "Brines are a credible alternative to the toxic mineral acids used for metal processing because of their low price.

"We are now trying to apply the same approach for different metals from different sources of waste, such as smartphones, thermoelectric materials and magnets."

The team say the new process gets more than 90% of the aluminium and silver from the solar cells in just 10 minutes and that the quality of the silver is high so it can be reused easily.