A new method for recovering gold from discarded electronics is paying back $50 for every dollar spent, according to researchers - who found their gold-filtering substance in cheesemaking, of all places.
In a new study, researchers from ETH Zurich, Switzerland, have detailed a sustainable, cost-effective method of extracting gold from electronic waste or e-waste. “The fact I love the most is that we’re using a food industry byproduct to obtain gold from electronic waste,” said Raffaele Mezzenga. “You can’t get more sustainable than that!”
The byproduct Mezzanga is referring to is whey, the watery portion of milk that separates from the curds when making cheese. The researchers managed to turn this dairy waste into a matrix of protein amyloid fibrils and successfully used it to selectively remove gold from e-waste.
In their paper, the researchers demonstrated their method’s commercial viability. Including both source material procurement costs and the energy costs for the entire process, the total cost of recovering 1 g of gold from e-waste was 50 times lower than the value of the gold recovered.
E-waste represents 2 percent of America's trash in landfills, but it equals 70 percent of overall toxic waste. In 2019, the World Health Organisation estimated that 53.6 million tonnes of e-waste was produced globally, but only 17.4 percent was documented as formally collected and recycled. So, this new invention by ETH Zurich can only be good news.
The researchers plan to ready the technology for the market. While e-waste is a promising starting source to extract gold, they are eyeing others, including industrial waste from microchip manufacturing or gold-plating processes.