Recycling of gold from electronics: Cost-effective use through 'design for recycling'

Abstract

With over 300 tonnes of gold used in electronics each year, end-of-life electronic equipment offers an important recycling potential for the secondary supply of gold. With gold concentrations reaching 300-350 g/t for mobile phone handsets and 200-250 g/t for computer circuit boards, this "urban mine" is significantly richer than what is available in primary ores. However, the "mineralogy" in scrap products is much different than in the conventional ores in a gold mine: Up to 60 different elements are closely interlinked in complex assemblies and sub-assemblies, and this requires specialised metallurgical processes with extensive offgas treatment to recover gold and a wide range of other metals cost effectively and in an environmentally sound way. Moreover, the logistics to "excavate" and "haul" the scrap products to the concentrator and further to the smelter are much more challenging than in the primary supply chain. Currently, only a small portion of old products is collected and directed into state-of-the art recycling chains. Significant improvements are needed here to fully utilise this secondary metal resource. The importance of the gold content of scrap electronics to the economics of recovery of gold and many other valuable metals is not always appreciated and this impacts on the 'design for recycling' approach in selecting materials for new products, particularly in the European Union where the WEEE Directive aims to provide a closed loop economy. With a lower carbon footprint than primary-mined gold, recycled gold represents an important 'green' source. The challenges faced in recycling electronic scrap to achieve a closed loop economy are discussed.