Life cycle analysis for solvent extraction of rare earth elements from aqueous solutions

Abstract

Recently Rare Earth Elements (REEs) have received increased attention due to their importance in many high-tech and clean energy applications. Although production of REEs is known to be heavy polluting, very limited environmental Life Cycle Assessment (LCA) studies have been conducted. This is particularly true for the solvent extraction of REEs from aqueous solutions, a key step in the REE production pathway. In this study, an LCA is carried out on a typical REE solvent extraction process using P204/kerosene. The material and energy flow data were based on production information collected from several solvent extraction facilities in Inner Mongolia, China. The life cycle inventory was developed using Simapro 7.1 and Ecoinvent 3, in combination with mass/energy balance and stoichiometry. Eco-indicator 99H was used for impact assessment and LCA results were used to evaluate and identify environmental hotspots of solvent extraction process. Moreover, challenges and opportunities for improved environmental performance of solvent extraction process were discussed.