Why Seawater Desalination Brine Is a Hidden Source of Essential Raw Materials

By Owais AliReviewed by Laura ThomsonOct 21 2024

Sea4Value is an innovative project to recover valuable minerals and metals from seawater desalination brines, transforming this overlooked byproduct into a crucial raw material source for Europe.

Image Credit: Fahroni/Shutterstock.com

The project focuses on extracting critical elements, such as magnesium, lithium, and scandium, essential for renewable energy, electronics, and advanced manufacturing industries.

Supported by the EU's Horizon 2020 program and 16 partners across eight countries, this project helps secure Europe's local supply of critical materials and reduce reliance on imports. Its success will yield significant commercial and environmental benefits for the raw materials industry.¹

Brine Mining: A Sustainable Solution for Critical Minerals Recovery

The European Union recognizes critical metals like antimony, cobalt, and tantalum as essential due to their societal applications, dwindling resources, and geopolitical instability.²

Traditional strategies to address these challenges, such as exploiting low-quality ores and recovering materials from industrial waste, are often inefficient and costly, leading to suboptimal recovery rates and increased environmental impact.

However, seawater desalination brine has emerged as a valuable source for mineral extraction, as it contains source minerals at twice the concentration of regular seawater. With global desalination capacity projected at 90–150 million cubic meters per day, mining these brines can recover valuable elements and mitigate supply shortages.³

How Is Sea4Value Extracting Minerals from Brine?

Sea4Value is the first attempt to cost-effectively recover minerals and metals from brines produced in seawater desalination plants through a multi-mineral and modular brine mining process.

The process begins with a pre-treatment phase that removes calcium using a precipitating reagent. This is followed by nanofiltration, where high-pressure membranes separate minerals into distinct streams to sequentially extract targeted metals.

The project focuses on extracting, concentrating, and crystallizing ten minerals/metals: molybdenum, magnesium, scandium, vanadium, gallium, boron, indium, lithium, rubidium, and calcium.

In the first 30 months, the project will validate the technologies for separating, concentrating, and crystallizing ten metals and minerals in laboratories. Subsequently, in the final 18 months, a mobile laboratory will be designed and installed at two operational plants in different oceanic environments: the Mediterranean (Denia, Spain) and the Atlantic (Fonsalia, Canary Islands, Spain), to assess technical feasibility.⁴

Video Credit: ESCI - European Science Communication Institute/YouTube.com

Key Technologies in the Sea4Value Brine Mining Process

Sea4Value uses ten advanced technological solutions to achieve high-purity metal extraction while minimizing environmental impact.⁵

Table 1: Technologies Employed by Sea4Value for Separation, Concentration, and Crystallization of Minerals. Source: Sea4Value

Innovative Approach

Multi-mineral modular approach

Most projects that focus on metal and mineral recovery from brines typically target individual elements, often rendering processes economically unfeasible. In contrast, Sea4Value integrates multiple advanced separation technologies to develop a technically and economically viable multi-element recovery process within a moving laboratory in a desalination plant. This configuration enables efficient on-site extraction of materials, reducing overall reagent consumption.⁴

Selective calcium removal for efficient recovery of critical elements

A key limitation in recovering trace critical elements from reverse osmosis brine is the presence of major divalent elements, particularly calcium, which interferes with the separation process and causes scale formation.

Sea4Value addresses this by implementing a selective calcium removal process, exploiting the differences in hydration between calcium and magnesium ions to facilitate calcium carbonate precipitation while minimizing magnesium co-precipitation.

They use thermodynamic modeling to optimize calcium removal conditions and then employ nanofiltration to separate magnesium and targeted trace elements further. This innovative approach improves recovery rates and integrates sustainable technologies, including membrane distillation and solar heating, to achieve near-zero liquid discharge, transforming brine into a valuable resource for critical raw materials.⁵

Commercial and Environmental Impact on Sea4Value’s Project

Sea4Value aligns with global trends toward sustainability and circular economies. It enhances the efficiency and sustainability of desalination plants by generating an additional revenue stream through mineral extraction. This approach can help offset the high energy costs associated with desalination, making freshwater production more economically feasible in regions facing water scarcity.

The project addresses the rising global demand for critical minerals essential for clean energy technologies, such as lithium and magnesium for electric vehicle batteries and scandium and gallium for solar panels and LEDs. It also aims to enhance Europe's resource independence by establishing a local supply of these vital raw materials, diminishing reliance on imports.

It also facilitates the transition to cleaner energy solutions while reducing reliance on traditional mining practices, often resulting in substantial environmental degradation.

As a circular economy initiative, Sea4Value has significant potential for job creation, ranging from skilled production site workers to specialized technicians, entrepreneurs, and raw materials brokers. In addition, it maintains a low environmental footprint by utilizing minimal and eco-friendly reagents while recycling waste streams, such as solvents and chemicals, to minimize resource consumption and waste discharge.

This holistic approach promotes sustainability and establishes a new standard for resource recovery in the water treatment industry.⁴

Comparison with Similar Projects

The main advantage of Sea4Value's approach is its capacity to simultaneously extract multiple metals from seawater brines, significantly enhancing efficiency and reducing costs compared to single-element recovery methods.

Unlike other projects, Sea4Value targets high-ionic seawater brines, utilizing advanced solvent extraction and nanofiltration techniques to recover a wider range of critical materials. Its scalability and compatibility with desalination plants in diverse oceanic environments further distinguish it from other methods.^6,7,8

Table 2. Comparison of Sea4Value with Similar Projects

Conclusion

Sea4Value addresses the rising global demand for critical raw materials for renewable energy and electric vehicles by providing secure, local sources, reducing Europe's dependence on imports and stabilizing supply chains.

The successful implementation of its technologies could transform desalination plants worldwide into multi-mineral extraction facilities, providing clean water resources and a sustainable alternative to traditional mining methods.

This innovative approach positions Sea4Value as a global model for resource recovery, contributing to a circular economy and enhancing sustainability efforts.

References and Further Reading

1. Sea4Value. (2024). Mining Value from Brines. https://sea4value.eu/wp-content/uploads/2024/04/20240327_Sea4Value_Brochure_21x21cm_WEB.pdf
2. European Commission. (2020). Study on the EU's List of Critical Raw Materials (2020): Final Report. https://doi.org/10.2873/11619
3. P. Loganathan et al. (2017). Mining valuable minerals from seawater: A critical review, Environ. Sci. Water Res. Technol. 3, 37–53. https://doi.org/10.1039/c6ew00268d
4. Sea4Value. (2024). The Project. [Online] Available at: https://sea4value.eu/the-project/
5. Molinari, R., et al. (2022). Can Brine from Seawater Desalination Plants Be a Source of Critical Metals? [Online] Available at: https://www.chemistryviews.org/details/ezine/11347408/can_brine_from_seawater_desalination_plants_be_a_source_of_critical_metals/
6. TRU Group. (2024). TRU Group Lithium & Brine Industries. [Online] Available at: https://trugroup.com/lithium-battery
7. Olokun Minerals. (2024). Ensuring a sustainable future through brine mineral mining. [Online] Available at: http://olokunminerals.com/
8. Brine Miners. (2024). Brine Miners - Extracting Value, Reducing Waste. [Online] Available at: https://research.engr.oregonstate.edu/brineminers/home

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