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The gold present in old cell phones, routers, modems, motherboards, and televisions appears in tiny layers used for conductivity and corrosion resistance. Researchers from ETH Zurich have created a protein sponge with whey capable of capturing metal ions and transforming electronic waste into sustainable and safe urban mining.
The gold may be hidden in household items that many people treat as junk, such as old cell phones, routers, modems, motherboards, televisions, and even unused appliances. The metal appears in small but valuable quantities in the internal circuits of these devices.
The novelty lies in a technique developed by Swiss scientists, which uses whey to recover the precious metal from electronic waste. The discovery reinforces the potential of urban mining but also raises an alert: extracting gold at home is dangerous, toxic, and should not be done domestically.
Gold appears in forgotten electronics inside the house
Old cell phones, dusty routers, stored modems, dismantled computers, and unused televisions may carry small amounts of gold in their internal components. The metal is usually found in connectors, chips, and metallic tracks.
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The amount in each device is very small, but the value becomes apparent when electronic waste is processed on a large scale. Therefore, household junk that seems useless can become raw material for industrial recovery processes.
Gold is used in these devices because it conducts electricity very well and resists corrosion. In delicate components, this resistance helps keep connections working for longer.
Even after the device stops working, the precious metal remains there. The problem has always been recovering this material efficiently, cheaply, and with less pollution.
Why the industry uses 22-carat gold in circuits
The electronics industry uses very thin layers of gold at strategic points in devices. The goal is not luxury, but technical performance, as the metal helps maintain good electrical conduction and stability in connections.
Unlike other metals, gold does not oxidize easily. This characteristic is decisive in communication equipment, computers, and devices that depend on reliable contacts.
In many cases, gold appears in layers so thin that it goes unnoticed. To the consumer, the device seems just like an old electronic; to specialized recycling, it may contain a small fraction of precious metal.
This presence helps explain why electronic waste has become a target for research. The sum of millions of discarded devices can represent an urban stock of valuable metals.
One ton of boards can concentrate valuable metal
The most striking data is in the circuit boards. One ton of boards can contain up to 150 grams of gold, a high content when compared to many traditional mineral sources.
This does not mean that anyone can get rich by dismantling electronics at home. Recovery requires scale, technology, and chemical control, because the metal is mixed with various other materials.
Electronic waste combines metals, plastics, solders, chemical compounds, and sensitive components. Separating everything without contaminating the environment is precisely the big challenge.
That is why the Swiss discovery draws attention. It offers a way to recover gold without relying on the more aggressive methods normally associated with traditional extraction.
Swiss scientists use whey to capture gold
Researchers from ETH Zurich have developed a sponge made of protein nanofibrils derived from whey. This structure can capture gold ions present in solutions obtained from electronic scrap.
The proposal is to transform a common byproduct of the food industry into a tool for urban mining. Whey, which is often treated as a byproduct, now has a technological function in the recovery of precious metals.
The process works through selective absorption. The sponge attracts gold ions and leaves other metals in the background, increasing recovery efficiency.
Then, the captured material undergoes controlled heating, forming metal flakes. These flakes can be melted into a small nugget.
Experiment recovered 22-carat gold nugget
In the laboratory, scientists processed 20 old motherboards and managed to recover a 22-carat gold nugget weighing 450 milligrams. The result showed that the method can be efficient even from discarded equipment.
The estimated cost of the process was 1 dollar, while the value of the recovered gold reached 50 dollars. This difference helps explain why the technique has sparked economic and environmental interest.
Scale is still an important point. The experiment shows potential, but turning the technology into a broad operation depends on infrastructure, collection, sorting, and proper processing.
Even so, the advancement indicates a promising path to recover metals from discarded devices without increasing pressure on traditional mines.
Home extraction is dangerous and should be avoided
Despite the appeal of the discovery, trying to extract gold at home is a dangerous practice. Improvised methods may involve toxic products, harmful gases, and direct health risks.
Some traditional extraction methods use substances like mercury and cyanide, in addition to processes that can release harmful vapors. Burning boards and electronic components can also contaminate the air and cause severe damage.
The safe path is proper disposal at electronic waste collection points. This way, materials can proceed to appropriate industrial processes, with environmental control and worker protection.
In Brazil, there are thousands of collection points spread across places like supermarkets, shopping malls, and subway stations. This type of disposal helps remove valuable metals from drawers and landfills.
Urban mining can reduce pressure on new mines
Urban mining starts from a simple idea: recover valuable materials already extracted from nature and present in discarded products. In the case of electronics, this includes gold, copper, silver, palladium, and other metals.
This logic can reduce the need to open new mining areas, as well as decrease waste sent to landfills and recover economic value from obsolete equipment.
The environmental impact of conventional mining can be high, especially when it involves large soil movement, energy consumption, and chemical use. Technological recycling attempts to reuse what already circulates in cities.
The technique with whey stands out because it combines the reuse of electronic waste and the use of an organic byproduct, creating a solution more aligned with the circular economy.
Item treated as scrap becomes a strategic resource
The old stored modem, unused router, and drawer cell phone represent a change in perception. What was once just waste is now seen as a stock of critical materials.
This change matters because the world produces more and more electronics and discards equipment at an accelerated pace. Without efficient recycling, valuable metals are lost in landfills while new mines continue to be explored.
The recovery of 22-carat gold in the laboratory shows that value is hidden in almost invisible layers. The difference lies in the technology capable of safely separating this metal.
With cleaner methods, urban mining can cease to be a distant promise and become a real part of the electronic reuse chain.
Hidden gold in electronics changes the idea of waste
The gold present in old household devices shows that electronic scrap can be worth much more than it seems. Cell phones, routers, modems, motherboards, and televisions hold small amounts of precious metal that, on a large scale, can become an economic resource.
The Swiss technique with whey opens a more sustainable path to recover this material, without encouraging dangerous homemade practices. The future of urban mining depends precisely on transforming proper disposal into safe, clean, and viable recovery.
The biggest challenge now is to expand collection, technology, and awareness. After all, part of the gold that could return to the industry is still sitting in drawers, storages, and forgotten devices.
And you, do you have any old electronics stored at home that could go to recycling, or do you still find it difficult to see value in this type of scrap? Share your opinion.
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