Date of Award
Master of Science in Mechanical Engineering (MSME)
Committee Member 1
Wallace E. Tyner
Committee Member 2
The clean-energy industry has been expanding drastically over the past decade with economically scalable technology and favorable policies. Rare earth elements (REEs), with unique chemical and physical properties have played a key role in this boom by improving the efficacy of certain cleanenergy products. For example, rare earth based magnets have a higher maximum energy output, reducing the size and weight of magnets in wind turbines and electric vehicle motors. However, its benefits are undercut by the drastic environmental impacts on the areas surrounding the mining and processing sites. Existing literature provides some information on these impacts but often fails to give a detailed process and material flow that can be utilized by researchers or decision makers without preexisting knowledge of life cycle analysis (LCA) and access to dedicated LCA software. To overcome this hurdle, an easily understandable and open-source Excel based package is created to calculate and model the environmental impacts of rare earth compounds and products. The detailed life cycle analysis can help identify environmental hotspots and judge the efficacy of potential improvements in the production process. EcoSpold data exchange format is adopted, which allows users to import/export the Excel files to an LCA software. The cradle-to-gate model of rare earth compounds and its products is created using two source deposits in China – Bayan Obo mines and South China clays. Extensively using industry reports and academic papers, a detailed material inventory for each production process is built. These include some REE products that have never been studied before, for example, rare earth phosphors. Analysis of the inventory data shows that South China clays produce 15 unique rare earths while Bayan Obo deposits produce only 4 rare earths of significant quantity. The difference in the number of REEs from each deposit is due to the inherent REE composition of the minerals. The results indicate South China clays based rare earth oxide production have a lower environmental footprint in most impact categories except acidification and eutrophication. Overall, the energy consumption and emissions to water have the highest contributions to the global warming, acidification, and eutrophication potential of REEs. Acknowledging these results, the ideal scenario would be to implement waste water treatment and move towards low-carbon energy sources.
Arshi, Praneet Singh, "An open-source life cycle analysis tool for rare earth products critical to the clean-tech industry" (2017). Open Access Theses. 1248.