Have you ever wondered what happens to your old computers or smart phones after you discard them? Although they may appear to be junk, they are, in fact, gold mines. With the increasing demand for gold and the staggering 62 million tonnes of e-waste disposed of globally in 2022, scientists are discovering innovative ways of recycling gold from waste electronics.
A revolutionary, eco-friendly technique for recycling 22-carat gold from old computers’ motherboards was announced by a team of scientists from ETH Zurich, headed by Raffaele Mezzenga. The innovators have resorted to the use of the dairy industry's waste product, which is known as whey, a liquid byproduct of cheese production, to create a ‘protein sponge.’
The method is just as interesting as it is eco-friendly. Raffaele and his colleagues denature whey proteins by exposing them to high temperatures and acidic environments. This produces amyloid fibrils, which are then freeze-dried into a sponge-like material. When this sponge material is dipped into a solution containing dissolved motherboards, it selectively binds to the gold particles.
In their experiment, the Swiss team was able to recover 450 milligrams of pure gold from just 20 old motherboards. The economic benefits are obvious; the cost of energy and materials used is 50 times less than the value of the extracted gold.
A greener future for mining
This is happening alongside other worldwide efforts to break away from these toxic processes of extraction. The conventional process of mining is done through cyanide and mercury, which are extremely destructive for nature. But these emerging methods of trichloroisocyanuric acid (TCCA) and polysulfide polymers are providing a chance for a safer form of mining, not just for ores but also for electronic scrap.
This is also a step towards a greener future, where this ‘gold mine’ inside your device is not thrown away but is instead recycled into the economy when you decide to upgrade your device again.
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