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.

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Rare earth elements (REEs) have found applications in the aerospace, automotive, consumer electronics and lighting industries, among others. A special class of REEs known as heavy rare earths (HREEs) is of particular importance to energy applications. With the growing clean energy technologies incorporating HREEs, it is valuable to examine their environmental emissions and energy requirements. Currently, extraction of HREEs is mainly carried out in China, where they are extracted mainly via open pit mining of bastnasite and/or monazite and leaching of ion-adsorption clays. Leach mining varies significantly from open pit mining technique in that the ores have much lower REE content but REEs stay as cations thus there is no need for physical and chemical beneficiation. To date limited life cycle assessment (LCA) studies have been done on REEs production and all of them are for the bastnasite/monazite route. This paper presents the first LCA of in-situ leach mining of REEs from ion adsorption clays in southern China. The function unit was defined as production of 1 kg of mixed rare earth oxides (REOs) of purity 92%. Ecoinvent 3.0 database was adopted for inventory analysis with material and energy flow information gathered from Chinese literature. To facilitate the use of results in U.S. and EU, TRACI and ILCD in SimaPro 8 were used for environmental impact assessment and cumulative energy demand was also considered as one additional category. The results showed that the environmental impacts for REOs derived from ion adsorption clays are similar in

A bioleaching process to extract rare-earth elements (REE) from fluidized catalytic cracking (FCC) catalysts was optimized using a heterotrophic bacterium Gluconobacter oxydans to produce organic acids from glucose. Parameters optimized included agitation intensity, oxygen levels, glucose concentrations, and nutrient additions. Biolixiviants from the optimized batch process demonstrated REE leaching efficiencies up to 56%. A continuous bioreactor system was subsequently developed to feed a leach process and demonstrated leaching efficiencies of 51%. A techno-economic analysis showed glucose to be the single largest expense for the bioleach process, constituting 44% of the total cost. The bioleaching plant described here was found profitable, although the margin was small. Lower cost carbon and energy sources for producing the biolixiviant, sourcing FCC catalysts with higher total REE content (>1.5% by mass), and improved leaching efficiencies would significantly increase the overall profit. A life cycle analysis showed that electricity and glucose required for the bioreactor had the largest potential for environmental impacts.

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