City gold mines!
Posted on July, 22nd 2015.
Our cities are full of hidden treasures. Proponents of urban mining have dug deep to find tomorrow’s mines in today's cities.
More gold can be extracted from a ton of cell phone electronic circuits than from a ton of ore.
Waste is piling up in landfills in every corner of the world, raw materials are becoming scarce and extraction processes are increasingly complex, costly and inefficient.
Raw materials are mostly shipped to cities. Industrialized countries have accumulated a significant amount of minerals and metals while constructing buildings, airplanes, household appliances, mobile phones, and developing ever more sophisticated technologies (especially in the field of renewable energy). Natural deposits are becoming scarcer, but our cities are veritable urban mines! Aluminum, copper, platinum, rhodium, palladium... Because of their intrinsic properties, these metals can be recycled almost endlessly.
But this hidden urban wealth is untapped.
Using a circular economy approach, urban mining consists of extracting minerals and metals from condemned buildings, aircraft at the end of their lives, and unusable electrical and electronic appliances. It’s a particularly interesting concept because it transforms cities from consumers into production centers and means we can start thinking about waste not as a burden but as an opportunity.
Let’s look at electronic devices. The screens on our mobile devices and televisions hide dozens of precious metals and rare earths (a group of 18 chemical elements with exceptional properties), all of which are essential for manufacturing a wide range of components. A smartphone for example contains an average of 300 mg of silver and 30 mg of gold, along with neodymium, terbium and yttrium, tantalum, lithium, aluminum, etc. However, globally only 15 to 20% of electronic waste is recycled. But more gold can be extracted from a ton of cell phone electronic circuits (about 150g) than from a ton of ore (approximately 5g) !
Our streets too are covered with precious metals: catalytic converters, in particular, throw out tiny amounts of platinum, palladium or rhodium in the atmosphere. Extracting them from street sweepings (urban cleaning) enable to reuse them. Another great example of circular economy !
Although urban mining presents some major challenges, the potential is huge. Recovering the raw materials concentrated in cities could well become a major and less polluting source of metals, and would simultaneously achieve significant energy savings and reduce the volume of waste.
Find out more:
Fairphone organizes urban mining workshops to train users to dismantle their phones and identify the different components to recover precious metals.