Friday, August 21, 2009
a scientist at Imperial College London, is looking into novel ways to recover metals from circuit boards. In most recycling plants, electronic waste is shredded and then separated into different types: plastic, glass and circuit boards. Anna has developed a system where shredded circuit boards are put into a large bath of acidic salty water. This dissolves the metals from the plastic backing so that they can be disposed of safely. The metals are then removed from the tank by passing an electrical current through the liquid. The current causes the metals to collect on metal beads in the tank and by changing the voltage, Anna can choose the metal she wants to precipitate. "It lets recyclers remove poisonous metals as well as precious ones, at virtually no extra cost. So there's no excuse for sending nasty stuff to landfill", says Anna. Recovering useful metals is of no small significance either, if we threw away all upgraded phones every year, we'd be kissing goodbye to 3750kg of silver and 600kg of gold.