Secondary Recovery from E-Waste
Also: urban mining, e-waste recycling, secondary metal recovery
Urban mining refers to the targeted recovery of precious metals and other valuable materials from electronic waste, end-of-life devices and industrial waste streams as a complement to primary mining.
Modern electronic devices are packed with precious metals: a smartphone contains gold, silver, palladium and copper in tiny but measurable quantities. Urban mining - literally "city mining" - taps exactly this "above-ground ore body" of discarded devices, industrial waste and end-of-life vehicles. Compared with primary production, the precious-metal content of electronic waste can be ten to a hundred times higher than that of a typical gold ore seam.
Why electronic waste is so valuable
The concentration of critical metals in e-waste far exceeds that of primary deposits:
| Source | Gold (g/t) | Silver (g/t) | Palladium (g/t) |
|---|---|---|---|
| Gold ore deposit (mining) | 1-5 | - | - |
| Circuit boards (mobile phones) | 300-400 | 1,000-3,000 | 30-100 |
| Catalytic converters | - | - | up to 7,000 |
| CPU processors (old) | 500-3,000 | various | various |
These concentration figures make urban mining economically attractive - especially when palladium prices and gold prices are high.
The recycling process step by step
- Collection and sorting - end-of-life devices are separated by category (smartphones, circuit boards, catalytic converters, cables).
- Mechanical processing - shredding, sieving and air separation divide out plastics, ferrous metals and non-ferrous metals.
- Pyrometallurgy - smelting in a furnace or converter; precious metals collect in the copper-lead alloy (the so-called black-copper route).
- Hydrometallurgy - wet-chemical leaching with acids or aqua regia, with selective precipitation of the individual metals.
- Affinage / refining - specialised refineries (e.g. Umicore, Heraeus) refine the metals to investment fineness and produce certified bars or granules.
Precious-metal yield approx. input mass x fineness x extraction rate
Example: 1 kg of circuit boards x 0.035% Au x 95% = approx. 0.33 g fine gold
You can determine the resulting melt value for scrap gold or industrial material directly online.
Significance for the global precious-metals market
Secondary metals from urban mining now cover a substantial share of global demand:
- Gold: recycling (jewellery + industry) accounts for around 25-28% of annual total supply, according to the World Gold Council.
- Silver: industrial recycling contributes around 15-20% of total supply.
- Palladium: catalytic-converter recycling supplies a steadily growing share - significant, since palladium is rarely mined as a standalone primary metal but is usually recovered as a by-product of platinum or nickel production.
Increasing electrification (e-mobility, solar installations, data centres) raises both consumption and the future potential of the recycling stream.
Legal framework in the UK and the EU
In the UK, the Waste Electrical and Electronic Equipment (WEEE) Regulations oblige producers to take back and properly dispose of equipment. The EU Battery Regulation (2023) tightens recycling requirements for lithium batteries. For consumers, returning devices to retailers and municipal collection points is free of charge.
Note: the tax treatment of proceeds from the sale of recycled materials depends on the individual case - this is not tax or investment advice.
In brief
Urban mining closes the metal loop: electronic waste contains precious metals at concentrations that exceed many primary deposits. Anyone wanting to check the current purchase price for recovered material will find suitable calculators on this site.