Extraction of Yttrium from Waste: Analysis of Hydrometallurgical Processing by Organic Acids and Life Cycle Assessment

The increasing demand for rare earth elements has driven the search for efficient and sustainable recovery methods. Obsolete fluorescent lamps represent a significant secondary source of Y that can greatly contribute to the circular economy and the preservation of natural resources. With the gradual depletion of primary Y reserves and the rise in e-waste generation, the development of eco-friendly and economically feasible recovery techniques has become crucial. Additionally, strict legislation regarding the disposal of e-waste strengthens the need to improve recycling processes. This study aims to investigate the leaching of Y from obsolete fluorescent lamps by organic (C6H8O7, C2H4O2, and C2H5NO2) and inorganic acids (HNO3). We also seek to assess the environmental impact of this process through life cycle assessment (LCA). Leaching steps were performed with different acid concentrations, followed by selective precipitation with C2H2O4 for Y recovery. LCA was applied to evaluate the environmental impacts and identify critical points in the process. A high Y recovery rate (78.8% for C2H5NO2, 86.7% for C6H8O7, 100% for C2H4O2, and 95% for HNO3) was obtained with precipitation (C2H5NO2 and C6H8O7 liquor). Our environmental assessment revealed that leaching with organic acids presents a higher environmental impact due to production and disposal methods. The study demonstrated that it is possible to leach Y efficiently from fluorescent lamps using organic acids. The process may be a feasible alternative for large-scale Y recovery, improving organic acid production, and contributing to the sustainable recycling of e-waste and promoting the circular economy.