Process simulation-based LCA: Li-ion battery recycling case study

Purpose
Data availability remains a bottleneck for life cycle assessment (LCA) despite being an established method in evaluating potential environmental impacts. The use of digital process simulations (process simulation-based LCA) to generate data had been explored as a solution but mainly applied as an assessment tool. This study aims to identify the strengths and limitations of this approach by expounding on its potential to be an eco-design tool starting at the conception phase of a process.
Methods
To achieve this, a hydrometallurgical and a pyrometallurgical recycling process were designed from literature and assessed in separate case studies. Recycling processes, especially for Li-ion batteries, are actively researched around the world today because of the critical metals it contains, and the role batteries play in achieving sustainability targets. A literature review of current recycling approaches for LIBs recycling was first conducted in order to design the processes to be assessed. Next, the goal and scope of the LCA case study were defined prior to simulating the chosen processes using HSC Chemistry®. Data generated from the simulation was used for the inventory, and the impacts were assessed using the Environmental Footprint (EF) 3.0 method in Simapro v9.6.
Results and discussion
The results showed that sulfuric acid and process emissions contributed most to the potential environmental impacts of the simulated hydrometallurgical treatment, while coke for the pyrometallurgical recycling process. This aligns with known concerns for these processes, i.e., hydrometallurgy can be reagent intensive, and pyrometallurgy specially smelting use carbon-containing materials as reductant, which shows that digital simulations could be a good source of information for the LCA. Another strength of simulation is the possibility to conduct digital experiments that could be time-consuming in a laboratory. Thermodynamic feasibility of the process being designed could also be confirmed. However, reaction kinetics are not completely considered thus the need for data validation through actual experiments is a recommended next step for this approach.
Conclusion
From the results, it can be concluded that the use of digital process simulation-based LCA can be a good approach in eco-designing processes. There is, however, a clear need for collaboration between process engineers and LCA practitioners to make sure that a well-informed digital simulation is used for the assessment, i.e., it should include validation of the simulation results based on the scaled-up data from laboratory and/or pilot-scale.