Review and new life cycle assessment for rare earth production from bastnäsite, ion adsorption clays and lateritic monazite

•The methodological challenges surrounding life cycle assessments for rare earths are identified by reviewing 24 publications•The main contributor to the global warming potential of the production of rare earth oxides for two of the three routes is solvent extraction.•Environmental impact assessment results from a monazite mining site in Mt. Weld, Australia are presented for the first time using primary data.•Two life cycle inventories are presented as the best representation of two of the three main mineralogical routes for rare earth elements. Rare Earth Elements (REEs) are one of the most important--albeit critical--commodities for our green technologies. However, there is a general perception that REEs are produced using mining and processing techniques that are unsustainable. Life Cycle Assessment (LCA) is the most widely accepted methodology to evaluate the environmental impacts of rare earth oxide (REO) production. This article aims to provide a synthesis of the currently existing LCA studies on REEs using two strategies. Firstly, an overview of published LCA results of REO production. Secondly, a detailed LCA using the best available life cycle inventories (LCIs) in order to: i). evaluate the state-of-the-art LCI for this sector ii). Understand better the impacts related to each of the three main production routes and iii). Contribute to the development of a preliminary benchmark for the sector. The analysis of the published LCA results reveal that the three main methodological issues with published LCAs are data gaps, allocation, and waste management. The dominating contributor to the global warming potential of the production of REOs in all two of the three routes is chemical extraction and separation.