Whey mushrooms extract gold from old circuit boards

E-waste is a big problem. The recycling process is often expensive and complex, so gold, copper and unusual materials used in manufacturing are rarely reused. Promising news on this front comes from a group of researchers ETH ZurichLed by Professor Rafael Mezenga.

Researchers have developed a sponge-like material made from whey protein that has proven to be more effective than traditional methods of extracting gold from electronics scrap. Researchers first dissolve metal pieces of circuit boards in an acid bath. The protein fiber sponge is then placed in the solution and selectively absorbs the gold ions. By heating the sponge, small golden flakes are formed that can be easily collected.

In the study, published In the scientific journal Advanced Materials, researchers showed how they were able to extract 450 milligrams of gold from 20 old motherboards using this technology. The gold was also relatively pure with about 91 percent gold and the remainder copper and trace elements. This corresponds to 21-22 carats.

Rafael Mezenga and other researchers also examined the total energy consumption and found that the technique extracts 50 times more gold than the total cost including materials and energy. The next step is to develop the technology so that it can be used on a large scale.