Silicon-based electrodes recover gold and copper from mining waste streams

A combined filtration and electro-extraction approach could help recover metals from dilute and complex liquids.

MIT spinout SiTration, USA, is collaborating with BHP Invent and Copper South Australia to trial its technology on copper samples over a five-week programme.

The system is said to combine silicon-based electrodes with a simplified processing approach to recover high-purity metals from waste streams. The company reports recovering gold at 99.99% purity from gold-containing streams and copper at 99.9% purity from residual waste liquids.

By simplifying processing routes, the technology could reduce the use of chemicals, energy and water associated with conventional mineral recovery. SiTration says the approach could also be applied to other critical minerals, including cobalt, nickel and rare-earth elements.

The company is initially targeting copper and gold waste streams from BHP assets, with potential future applications in recovering low-grade copper resources currently considered waste.