Assessing the Sustainability of Electrodialysis for Rare Earth Element Recovery from Phosphogypsum
Open Access
- Author:
- Brajovic, Alexandra
- Area of Honors:
- Chemical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Rui L Shi, Thesis Supervisor
Esther Gomez, Thesis Honors Advisor - Keywords:
- electrodialysis
life cycle analysis
techonoeconomic analysis
Excel
ED
rare earth elements
REEs
phosphogypsum
electricity
current
impact
openLCA
LCA
TEA
oxalic acid - Abstract:
- Electrodialysis (ED) has been sought as a method of rare earth element (REE) separation from phosphogypsum as a means to promote sustainable waste recovery and implement a circular economy. In order to handle large amounts of waste generated from mining activities, ED must be scaled up to industrial levels and evaluated as a continuous process of REE recovery, rather than as a batch or pilot-scale process, and evaluated for its environmental and financial impacts. A Life Cycle Analysis (LCA) was performed on ED using openLCA software, and the results were compared to an LCA performed on precipitation from oxalic acid. For financial impacts, a model was developed in Microsoft Excel with adjustable parameters to determine the capital and annual operating costs of an ED system that meets set production goals. Compared to precipitation from oxalic acid, ED has slightly higher global warming potential and fossil fuel consumption impacts but also displays significantly lower impacts for human and terrestrial toxicity. Financially, an ED system is economically viable; although multiple units running in parallel are required to meet production needs, the overall cost is dominated by capital costs, which scale with membrane size, which is driven by current applied to the unit. The initial investment will be made back after three years, and thus the ED system will be profitable over time.