A team of researchers from the University of Melbourne and King Fahd University of Petroleum and Minerals (KFUPM) has found a new, greener way to extract and purify metals from waste alloys and raw materials.
This innovative method could transform metal refining into a more energy-efficient and environmentally friendly process.
Traditionally, metals are separated using chemical treatments or extreme heat. These methods not only consume a lot of energy but also produce harmful waste.
The new approach takes a completely different path—using surface energy to separate metals.
This idea, based on a principle called “electrocapillarity,” has never been used in metal refining before.
Here’s how it works. When certain metals are melted together, they form liquid alloys. In these molten mixtures, some metals naturally move toward the surface depending on their surface energy.
The scientists discovered that they could take advantage of this by dissolving metal waste into low-melting-point metals like gallium (Ga), creating liquid alloys that stay fluid at or near room temperature.
The real magic happens when this liquid alloy is placed in a special solution, forming a boundary between two liquids. By applying a gentle electric charge, the team can change the surface tension of the alloy.
This triggers a separation process where metals with lower surface energy—such as bismuth (Bi), tin (Sn), and lead (Pb)—rise to the surface and can be pulled out one by one in a controlled order. This allows for precise metal purification without needing high temperatures or dangerous chemicals.
Dr. Mohannad Mayyas, who led the study, said the new technology has the potential to run on renewable energy, offering a truly “net-zero” refining process. “This discovery opens the door to sustainable metallurgy,” he explained.
“We can now think about refining metals more efficiently, with far less energy and without chemical waste.”
The process is also fast and accurate. Xichao Zhang, the study’s first author and a PhD student at the University of Melbourne, noted that they could quickly separate metals and control the purity and particle size with precision.
The team believes their discovery could be used to process difficult waste materials, including solder scrap, crude gallium, and industrial metal byproducts. Their next step is to scale up the process for industrial testing at KFUPM.
This breakthrough not only marks a major advancement in materials science but also contributes to a more sustainable future. It supports the growing push for cleaner industrial methods and promotes the recycling of valuable metals that would otherwise go to waste.
