Although light-emitting diode (LED) bulbs are more energy-efficient than fluorescent lights while in use, they can still pose a problem environmentally at the end of their service life. Mineral processing engineer Maria Holuszko and PhD student Amit Kumar from the University of British Columbia’s (UBC’s) urban mining program have developed a response to this issue, creating a recovery method for metals in LEDs.
LEDs contain numerous valuable metals, including:
- indium; and
- minimal amounts of gold and silver.
To avoid allowing these metals to be wasted in landfills, Holuszko and Kumar developed an urban mining workflow reliant on physical processes such as crushing and grinding. Inexpensive to implement and environmentally responsible, this method improves on the amounts of valuable metals that can be recovered from discarded LEDs.
The quantity of gold recoverable from LEDs is still insignificant with this approach, but recovery of other types of metals has improved substantially—for example, approximately 65 per cent of copper can be salvaged (compared to the 30 or 40 per cent retrievable with traditional methods). Holuszko and Kumar’s method permits six per cent of lead, 4.5 per cent of zinc, and 1640 ppm of silver to be reclaimed.
Tests evaluating the success of this method have already been conducted with the support of B.C. lamp recycler Contact Environmental. The team hopes to continue improving the process in 2017, ideally finding a means of improving gold recovery.