Life cycle assessment of electrodialytic technologies to recover raw materials from mine tailings

Currently, the development of new sustainable technologies to recover raw materials from secondary resources has shown a lack of available data on the processes and supplies involved, as well as their environmental impacts. The present research has conducted a life cycle assessment of electrodialytic (ED) technologies to improve critical raw materials recovery in the Portuguese mining industry. To critically appraise the activities from the mining sector and gather data on technical and environmental issues, three waste management scenarios were considered: (1) ED treatment with a deep eutectic solvent as an adjuvant; (2) ED treatment with simultaneous H₂ recovery; and (3) ED treatment with sodium chloride as an enhancement. The data presented were based on global databases, technical reports from official sources, and peer-reviewed published experimental outcomes. The estimated results indicated that one of the constraints in applying ED technologies is energy consumption and thus the impacts are highly dependent on energy source choices. On the other hand, as a consequence of the H₂ inherently produced by ED technologies, there is a direct potential for energy recovery. Therefore, considering an upscale approach of the ED reactor based on bench scale experimental results, the H₂ could be reused in the ED facility or stored. Additionally, according to experimental data, 22% of the tungsten from the fine mine tailings could be recovered. Finally, the possibility to remove 63% of arsenic from mine tailings could decrease contamination risks while creating additional marketable co-products.