97% of silver recovered from dead solar cells using acid-free molten salt bath

Researchers at Ningxia University in China developed an acid-free method that dips retired solar cells into a molten sodium and potassium hydroxide bath at 230 °C. The process recovers up to 97.11% of the silver while limiting silicon wafer loss to 2.62%. The study was published in the Journal of Cleaner Production on October 28.

• Molten NaOH-KOH bath at 230 °C recovers 94.34% of silver in 150 seconds
• Peak silver recovery reached 97.11%
• Silicon loss limited to 2.62% at 230 °C for 100 seconds
• Silver is under 0.03% of panel weight but nearly half its value