Rare earths from secondary sources: profitability study

The paper is focused on the economic analysis of two hydrometallurgical processes for recovery of yttrium and other rare earth elements (REEs) from fluorescent phosphors of spent lamps. The first process includes leaching with sulphuric acid and precipitation of a mixture of oxalates by oxalic acid, the second one includes leaching with sulphuric acid, solvent extraction with D2EHPA, stripping by acid and recovery of yttrium and traces of other rare earths (REs) by precipitation with oxalic acid. In both cases the REEs were recovered as oxides by calcination of the oxalate salts. The economic analysis was estimated considering the real capacity of the HydroWEEE mobile´s plant (420 kg batch-1). For the first flow-sheet the cost of recycling comes to 4.0 € kg-1, while the revenue from the end-product is around 5.40 € kg-1. The second process is not profitable, as well as the first one, taking into account the composition of the final oxides: the cost of recycling comes to 5.2 € kg-1, while the revenue from the end-product is around 3.56 €kg-1. The process becomes profitable if the final RE oxide mixture is sold for nearly 50 € kg-1, a value rather far from the current market prices but not so unlikely since could be achieved in the incoming years, considering the significant fluctuations of the Res´ market.