l'Actualité du Solaire

Scientists in Singapore have discovered a unique reagent (phosphoric acid-H3PO4) for recovering silicon from end-of-life photovoltaic panels. The recovery rate has reached the level of

98.9% (with a purity rate of 99.2%), much higher than the current dual-reagent method (based on nitric acid and potassium hydroxide) for separating metals from silicon cells.

According to the researchers, this reagent eliminates the need for any post-treatment. What's more, this reagent is also always used in the etching paste used to remove ARC. By directly targeting the ARC layer, it is able to separate silver (Ag) and aluminium (Al) from the wafer surface.

In comparison, the two-reagent method requires both acid and alkali to be treated separately and requires post-treatment to remove the anti-reflective coating (ARC) from the recovered silicon. "In addition, the KOH step in the dual reagent approach has a detrimental effect on the recovery yield and purity of the recovered silicon."

Recovered silicon is of similar quality to new silicon purchased commercially

https://www.pv-magazine.com/2023/09/14/single-reagent-tech-to-reuse-silicon-from-end-of-life-pv-panels-achieves-recovery-rate-of-98-9/

PV Magazine 14 September 2023