One of the most promising yet underutilized sources of mineral recovery is brine: the concentrated waste stream generated by desalination plants, sea salt production, mineral processing etc. Conventional desalination processes produce two primary output streams: freshwater and brine concentrate. While freshwater is the intended product, brine concentrate is often discarded as waste, despite being rich in dissolved salts and valuable minerals. Sea bittern, a specific type of concentrated brine obtained from solar evaporation during sea salt production, contains high concentrations of sodium, magnesium, and potassium salts [3], [4], making it a potential resource for recovery. Several studies have explored methods to extract these salts; however, existing approaches treat each recovery process as a separate problem, leading to a lack of a unified and systematic framework for mineral extraction from brine.
This study addresses this gap by developing a comprehensive and optimized framework for the separation and recovery of valuable marine chemicals from bittern. The proposed framework employs a combination of process optimization and superstructure optimization techniques to systematically evaluate and determine the most efficient separation pathways. A mixed-integer nonlinear programming (MINLP) model is implemented to explore a broad set of separation technologies, allowing for an in-depth evaluation of various process configurations. The use of superstructure optimization facilitates the identification of the most cost-effective and environmentally sustainable pathways for mineral recovery. To assess the viability of the proposed separation processes, a techno-economic analysis (TEA) is conducted, considering key economic factors such as capital investment, operational costs, and revenue potential. Additionally, a life cycle assessment (LCA) is integrated into the framework to evaluate the environmental performance of different feasible pathways, examining metrics such as global warming potential, human health impacts, ecosystem quality, and resource utilization.
The findings of this study highlight the significant potential of employing integrated process optimization techniques to develop efficient, cost-effective, and environmentally sustainable strategies for the recovery of valuable compounds from the bittern. By incorporating TEA and LCA into the framework, this research provides a holistic understanding of both the economic and environmental implications of different recovery pathways. The proposed approach serves as a decision-making tool to guide the selection of optimal separation technologies, ultimately contributing to the sustainable utilization of saline resources and reducing waste in related operations.
References
[1] O. Ogunbiyi et al., “Sustainable brine management from the perspectives of water, energy and mineral recovery: A comprehensive review,” Desalination, vol. 513, p. 115055, Oct. 2021, doi: 10.1016/j.desal.2021.115055.
[2] A. Panagopoulos, “Water-energy nexus: desalination technologies and renewable energy sources,” Environ. Sci. Pollut. Res., vol. 28, no. 17, pp. 21009–21022, May 2021, doi: 10.1007/s11356-021-13332-8.
[3] P. Sahu, B. Gao, S. Bhatti, G. Capellades, and K. M. Yenkie, “Process Design Framework for Inorganic Salt Recovery Using Antisolvent Crystallization (ASC),” ACS Sustain. Chem. Eng., Dec. 2023, doi: 10.1021/acssuschemeng.3c05243.
[4] P. Sahu, “A comprehensive review of saline effluent disposal and treatment: conventional practices, emerging technologies, and future potential,” Water Reuse, vol. 11, no. 1, pp. 33–65, Oct. 2020, doi: 10.2166/wrd.2020.065.