A newly developed technology is now being used to recover pure silicon from end-of-life solar cells.
The amount of material wasted in this industry can be reduced significantly with the use of new techniques. The technique promises to create 99.9984% pure recycled silicon.
Scientists from India’s KPR Institute of Engineering and Technology have found a way to recycle the silicon from solar cells. Scientists used a new technique that uses chemicals that are much less toxic than hydrofluoric acid. This makes it much safer.
This is a new way to recycle silicon from PV devices. It does not use hydrofluoric acid, which is an extremely toxic chemical and is usually used for cleaning and etching.
The corrosive acid was replaced with three different chemicals. A 10 M solution of sodium hydroxide (NaOH) was used to remove the aluminium layer for five minutes at 63 degrees Celsius. A 6 M solution of nitric acid (HNO3) was used to remove the silver electrodes and lead, and a 90% phosphoric acid solution was also applied.
The team say the proposed technique can make silicon with a purity of up to 99.9984% and it costs $68.9 to recycle 1 kilogram of silicon – which means a $185.4 profit per 1 kilogram of silicon processed.
The silicon from these cells can be reused. It can be made into new solar cells, or it could even be used for something like a computer chip. This recycling technique also lets you get aluminum, silver, and lead from the process.
The research was published as “Recovery of Pure Silicon and Other Materials from Disposed Solar Cells,” in the International Journal of Photoenergy.