Editor | Quantity Surveyor
A version of this analysis appeared on ScienceBlog.com.
Discarded solar panels carry silver at a concentration that would interest any mining company, yet most of that metal in Australia is currently heading straight to landfill.
Inside end-of-life panels, silver sits at roughly 300 to 500 parts per million, a grade comparable in some cases to the ore that dedicated silver mines are built around. By 2050, Australia is projected to be holding more than one million tonnes of retired panels, containing an estimated 300 to 500 tonnes of silver.
Individually, that amount looks small. A single panel holds around 20 grams of silver, worth roughly AUD 3.66 a gram, hardly enough on its own to justify a dedicated recycling line. Spread across a million tonnes of panels, though, the pile starts to resemble an ore body that has already been mined, shipped, and sorted into rectangles.
Only about 15 percent of used solar panels in Australia are currently recycled at all, and even then, processors typically reclaim just the glass and aluminium frame. The silver sits inside the solar cell itself, and extracting it has usually required acid-based chemistry that mainstream recyclers have not adopted.
Associate Professor Mahshid Firouzi, deputy director of the University of Newcastle’s Centre for Critical Minerals and Urban Mining, said the country is effectively burying silver in landfill when it has the ability to recover it. Her team has been testing an alternative approach borrowed directly from the mining industry.
The method involves crushing panels and running the ground material through froth flotation, a standard mineral-processing technique in which valuable particles cling to air bubbles in water and float to the surface. In an 18-month study published in December 2025, the researchers reported recovering more than 97 percent of the silver within minutes, without using acid.
The team followed that result with a continuous pilot trial in August 2026, processing about 22 kilograms of cell material drawn from roughly 460 kilograms of panels, equivalent to 23 typical rooftop modules. Researchers described the pilot as moving the process closer to commercial viability, though the near-complete recovery figure comes from a single trial rather than an operating plant.
A working extraction method does not by itself close the recycling gap. Panels still need to be collected, transported, and delivered to a facility equipped to process more than glass and frames, steps that remain largely unaddressed. What flotation changes is the economics once panels do arrive, concentrating silver into a product representing just 1.25 percent of the original cell material.
Whether the technique shifts Australia’s recycling rate beyond its current 15 percent likely depends less on the chemistry, which appears close to solved, and more on policy questions around collection and transport costs that have yet to be settled.
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