A reason for energy efficient lamps being important for resource efficiency and circular economy agendas has much to do with the rare and critical elements found in fluorescent and LED lamps. Rare earths are used on the phosphor coating of lamps to produce soft white light (a well as other colours of light). While rare earths for lighting only account for 7% of the global use by volume, they account for 32% of the market value. This is in large part to the high level of purity needed for high quality phosphors. Thus, sourcing rare earths to make this essential component is of great importance. The fact that China produces the overwhelming majority of rare earths also raises concerns about supply risks (and why these materials are on critical material lists in both the EU and U.S.)
These concerns were shown to be valid when China restricted the export of rare earths in from 50,145 tons in 2009 to only 31,130 tons in 2012. While rare earths are used only in small amounts in fluorescent lamps, and even smaller amounts in LEDs, this development was a big concern for the industry. It responded in a few ways. One was to look for substitutes, and there are currently developments to combine LEDs with different wavelengths to produce the white light spectrum, but work still needs to be done to make this as efficient as the current blue LED combined with phosphors.
Until this is more established however, another alternative was looking at how we can better recycle the rare earth materials already embodied in lighting products – through urban mining. This has been the subject of a few programmes on the Swedish national radio lately. Lamps are one of the best examples that this circular economy thinking can actually result in closing material loops. The case was demonstrated through a Life+ project in which Solvay-Rhodia set up a commercial-scale process for recycling the rare earth materials from collected waste lamps. However, Solvay-Rhodia have indicated that this project is not their best project economically and driven more by sustainability considerations. The question is why is this so – when you consider that secondary powders can contain 15 times the concentrations of hard rock REE bearing ores? This is a question we are currently looking at in our research.