Scientists unveil how dairy waste can extract 22-carat gold from motherboards

A team of scientists have penned a new study that details an interesting way to collect valuable minerals from electronic waste, and the method includes creating a sponge from dairy waste.

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The sponge has been detailed in a research article published in Advanced Materials, where the team explains this method is capable of retrieving $50 worth of gold for every dollar spent on the recycling process of e-waste.

So, how was this sponge created? The researchers looked at the process of making cheese and, in particular, amyloid nanofibrils. First, the team denatures the dairy proteins by heating the whey in an acid bath, which forms the amyloid nanofibrils that are then used to create the sponge. The electronic components are then melted down in the acid, which then creates a solution that is rich in gold and copper.

The sponge is then added to this gold and copper solution, and the dairy proteins then attract valuable metals. The team then heated the sponge again, turning the ionic solution into gold flakes that could be easily removed and then reheated into gold nuggets or even bars, depending on how much electronic waste was present. According to the study, the team was able to extract 450mg of 22-carat gold from 20 motherboards. The haul from 20 motherboards was approximately 91% gold and 9% copper.

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"The fact I love the most is that we're using a food industry byproduct to obtain gold from electronic waste ... You can't get much more sustainable than that," said Raffaele Mezzenga, ETH Zurich professor and co-author of the study.