A cleaner way to mine old solar panels recovers 98% of their silver

When a solar panel wears out, most of its value sits in a dusting of silver — only 0.1% to 0.5% of the weight, but about 60% of what the scrap is worth. The usual way to get it out uses nitric acid, which leaves behind harmful fumes and dirty wastewater. Researchers at France's Alternative Energies and Atomic Energy Commission (CEA) have found a gentler route: a wash that dissolves the other metals in under 10 minutes while the silver stays solid, wrapped in a protective shell. In lab tests and a 20-litre pilot reactor, the process recovered more than 98% of the silver at 97.2% purity — and the wash liquid can be used again several times over.

SDG 12 · Responsible consumption and production — Mechanism: tech innovation