Public defence, Processing of Materials, MSc Diana Arellano-Sanchez

Title of the thesis: Prospective life cycle assessment of hydrometallurgical battery recycling routes

Thesis defender: Diana Arellano-Sanchez
Opponent: Associate prof. Jouni Havukainen, LUT University
Custos: Prof. Mari Lundström, Aalto University School of Chemical Engineering

This thesis assessed novel battery recycling routes still in early development (low technology maturity). The study evaluated six hydrometallurgical routes, using process simulation to estimate inputs and outputs of the process and life cycle assessment (LCA) to quantify environmental performance.
The aim was to evaluate the environmental performance of these routes, when design choices can still be changed. This future-oriented approach identifies problematic areas in the process simulation and environmental hotspots in the LCA. This methodology identifies where further research is needed and where the greatest potential for improvement lies.

The overall results suggest that the six assessed hydrometallurgical routes bring environmental benefits compared with the mining of virgin materials. Nevertheless, it was identified that solvent extraction could become a hotspot in the process according to degradation in the system (0-5%). Future research should focus on routes that improve lithium recovery yields. Due to the nature of lithium recovery, which occurs in the final process steps of the battery recycling flowsheets, overall lithium recovery yields plateaued at 89% for the simulated flowsheets of this work. Moreover, further research is needed on Co and Ni recovery via solvent extraction, crystallization, and electrowinning, as the flowsheets meet the 2027 EU Battery Recycling Regulation targets (90%) but fall short of the 2031 (95%).  Although Mn, graphite, and TiO2 do not have specific targets in the EU Battery Regulation, their recovery would contribute to the mandated total recovered battery wt. target of 70% by 2030. Therefore, these materials should not be overlooked in battery recycling processes.

The results can guide researchers and technology developers in prioritising development efforts. The study also generated open data, which other researchers and LCA practitioners can reuse and build on. Hydrometallurgical battery recycling is a promising alternative to primary mining, but its performance depends strongly on key factors (e.g., reagent use, energy source, process configuration). Early-stage assessment is essential to improve development toward sustainable solutions.

Keywords: battery recycling, process simulation, LCA, environmental impacts, sustainability

Thesis available for public display 7 days prior to the defence at Aalto University's public display page.

Contact information: 
https://www.aalto.fi/en/department-of-chemical-and-metallurgical-engineering/hydrometallurgy-and-corrosion-hydromet?check_logged_in=1 
https://www.linkedin.com/in/diana-arellano-san/