Behind the Scenes of Clean Energy: The Environmental Footprint of Rare Earth Products

Abstract

Critical to the functionality of energy efficient lighting, off-shore wind turbines, and electric vehicles are rare earth (RE)-containing phosphors and magnets. With an increase in the market penetration of these clean energy technologies, demand for RE-containing components is expected to grow. However, the production of rare earth elements (REEs) has an adverse impact on the environment.Existing literature provides some information on the environmental impacts but often fails to give a detailed production pathway that can be modeled without preexisting knowledge of life cycle analysis (LCA) or a dedicated LCA software. In this study, life cycle inventories were compiled based on representative production pathways in China using facilitylevel energy/material data. Phosphors and magnets using REEs from monazite/bastnasite deposits in Bayan Obo as well as ion-adsorption clays from China's southern provinces are covered. Analysis of inventory data shows that electricity requirements and emissions to water have the highest contributions to the impact categories of global warming, acidification, and eutrophication. An interconnected Excel database system is also developed to help researchers and decision makers identify environmental hotspots and develop improvements in the production pathways.

Comparative Life Cycle Assessment of Neodymium Oxide Electrolysis in Molten Salt

“…This study focused on MSE of Nd 2 O 3 . As no primary data were available for MSE, previous LCA studies by Sprecher et al, [10] Zhao et al, [15] Lee and Wen, [16] Vahidi et al, [24] and Schreiber et al [14] had modeled the Chinese electrolysis process using different assumptions, e.g., regarding the state of the art. In this article, the proposed electrolysis processes were compared.…”

“…In this article, the proposed electrolysis processes were compared. Based on the studies by Sprecher et al, [10] Zhao et al, [15] Lee and Wen [16] (three electrolysis scenarios: best, middle, worst), and Schreiber et al [14] (four electrolysis scenarios: best, middle, worst, average), nine electrolysis processes were modeled and compared using GaBi software version 9.2.0.58 by Thinkstep [36] ( Table 1). In addition to these nine electrolysis processes, a future electrolysis process was established for the year 2030 to show improvement potentials.…”

“…Unit Zhao [15] Sprecher [10] Lee [16] best Lee [16] middle Lee [16] worst Schreiber [14] worst Schreiber [14] middle Schreiber [14] best Schreiber [14] average Lee and Wen [16] specified three NdF 3 production scenarios called Lee, worst (Lee/w), Lee, middle (Lee/m), and Lee, best (Lee/b) ( Table 1), which differed significantly in HF input and HF emissions. A description of these process variants was not given.…”

Chemical Thermodynamic Insights on Rare-Earth Magnet Sludge Recycling

“…31) Including the cost of water treatment and the energy needed for solvent handling and consumption, LCA analyses for hydrometallurgical treatment have estimated a contribution of 58 GJ/tonne RE to the footprint of rareearth processing. 33) We can calculate the energy required for molten salt electrolysis of one mole of RE metal using the Nernst equation:…”

Recent Advances in the Separation of Rare Earth Elements Using Mesoporous Hybrid Materials

“…Furthermore, a large number of extractants used in LLE suffer from poor selectivity among adjacent elements, thus consuming large volumes of high‐purity solvents upon repetitive extraction cycles, and generating a large amount of undesired and radioactive wastes. A life‐cycle assessment of the production of REEs shows that mining, leaching and solvent extraction have the largest contribution to the overall environmental footprint . This adverse impact caused by LLE contradicts the green chemistry and clean energy principles and could overshadow the potential of technologies relying on REEs.…”