A critical review of end-of-life fluorescent lamps recycling for recovery of rare earth values

The review presents a critical analysis of different recycling processes, recent advancements, market value potential for recycling waste fluorescent lamps (FLs), and recovery of rare earth elements. The limited primary resources, strict environmental norms, and the growing demand for rare earth elements call for global phosphor recycling from waste FLs. Commercial-scale collection and recycling of fluorescent lamps are currently practiced to separate mercury for safe disposal; however, processing associated phosphor powder rich in rare earth compounds is still evolving. Phosphor consisting of multiple rare earth minerals (Y, Eu, Ce, Tb, La) can be considered a potential secondary source. The literature findings show that research efforts lean towards combined pyro-hydrometallurgical processes because of higher recoveries and apparent dissociation of inert phases. Advanced processing techniques such as microwave processing and mechanical activation can significantly increase the recovery rate; however, limited scale-up guidelines are available. Recycling rare earth phosphor is analogous to ore processing with the advantage of reduced energy consumption and waste emission. Approximately 300 g of rare-earth compounds can be recovered from 1 kg of phosphor waste, analogous to the processing of 11.9 to 22.5 kg site-specific primary ore. Recycling fluorescent lamps for rare earth recovery may become inevitable globally because of prevailing looms of the rare earth supply chain.