University of Newcastle researchers have taken a major step towards solving Australia’s growing solar panel waste problem by scaling up an acid-free process that recovers nearly 100 per cent of silver from retired solar panels.
Demonstrated during the world’s first continuous pilot-scale flotation trial for solar recycling, the technology adapts a standard mining process, froth flotation, to separate precious metals using water, air, and small amounts of targeted reagents instead of harsh chemicals.
During the trial, the team processed 22 kilograms of solar-cell material recovered from roughly 460 kilograms of end-of-life solar panels.
The process concentrated almost all the silver into a high-value product representing just 1.25 per cent of the original material, boosting the silver concentration by more than 80 times.
Associate Professor Mahshid Firouzi, Deputy Director of the university’s Centre for Critical Minerals and Urban Mining (CRITIUM), said demonstrating continuous operation at scale brings the technology much closer to commercial reality.
“At the moment, recycling often costs more than landfill. But if recyclers can efficiently recover and sell the silver contained within solar panels, that changes the economics completely,” Firouzi said.
“This latest work demonstrates that the process can operate continuously at a much larger scale with nearly 100 per cent silver recovery, bringing us closer to commercial implementation.”
Recycling a solar panel currently costs between AU$10 and AU$15, compared to just a few dollars for landfill disposal. Preliminary economic assessments indicate this flotation-based method is three to five times cheaper than conventional acid-leaching methods, which require large volumes of expensive chemicals and produce hazardous waste streams.
With Australia expected to generate more than one million tonnes of waste solar panels containing up to 500 tonnes of silver by 2050, the innovation offers a financial incentive to build a circular domestic renewables economy.
“If we’re serious about building a circular economy, we need to think not only about how we generate clean energy, but also how we recover the materials that make those technologies possible,” Firouzi said.
The research team, based at the Newcastle Institute for Energy and Resources, is now investigating applying the physical separation technology to other critical e-waste streams, including decommissioned data centre circuit boards.