Assessing the energy requirements and global warming potential of the production of rare earth elements

The rare earth elements (REE) play an indispensable role in modern technology, especially in wind turbines, or as phosphors, catalysts, specialty alloys and others. Despite the benefits of REE, there has been minimal research assessing the environmental impacts of REE mining. Here, we present a “cradle to gate” scale life cycle impact assessment for 26 operating and potential REE mining projects, focusing on the gross energy requirement and the global warming impacts of the primary REE production stage. The results suggest that the declining ore grades of REE significantly increase the environmental impact of REE production. On a unit basis (such as GJ/t-metal or kg CO_2e/t-metal), REE production causes higher environmental impacts than common metals (e.g. Cu, bauxite, and steel), with the refining stage being responsible for the greatest proportion of these impacts. Changing the REE production configuration could lead to diverse environmental footprints associated with each project.