Crack open your dumb old phone, and you’ll find lots of circuits and no lack of precious metals. In 100,000 mobile phones, it’s estimated that there is 2.4kg of gold, more than 900kg of copper, 25kg of silver and more, according to Motherboard. Could a safer and and cheaper method of recovering that metal come by way of fungi?
Recovering gold from old electronics is profitable but not pretty. In Europe and the US, it requires the use of toxic chemicals like sulphuric acid and cyanide to dissolve out the precious metals. In developing countries where much of our e-waste is now sent, open-air burning releases toxic fumes.
Fungi, in comparison, are a gentler scavenger of gold. Finnish scientists at the VTT Technical Research Centre have figured out a way to filter out gold with biomats made of mycelium, the part of a fungi that lives underground. The first step is crushing the old phones into a fine powder. That powder is sieved and passed through the mycelium, which was chemically engineered to attract gold. The researchers say this process recovers 80 per cent of the gold, compared to just 10 or 20 per cent in the common but toxic chemical processes.
Tweaking the process for making the mycelium mats could allow them to recover other precious metals in e-waste. In fact, this is all a new twist old idea: mycoremediation. As natural decomposers, fungi are fantastic at breaking things down, like the goopy stuff from oil spills. And they can absorb toxic heavy metals, like lead, as they grow. Fungi seem poised to take over the world. Oh wait, they already have. [EE Times via Motherboard]