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Circular Processing of Seawater Brines from Saltworks for Recovery of Valuable Raw Materials

Periodic Reporting for period 2 - SEArcularMINE (Circular Processing of Seawater Brines from Saltworks for Recovery of Valuable Raw Materials)

Periodo di rendicontazione: 2021-12-01 al 2023-05-31

THE CHALLENGE
Europe currently depends on imports of raw materials that are critical for economic development. These EU classified Critical Raw Materials (CRM) are increasingly needed in a range of high growth industrial sectors, including advanced battery technology and polymer production, alongside pharmaceutical and nutraceutical applications. There is an urgent need for technological innovation, allowing for CRM production within Europe, which meets the highest expectations in terms of performance, cost and green credentials.

PROJECT OBJECTIVES
SEArcularMINE builds on the ancient and still widely used process of saltworks, where seawater goes through natural evaporation and crystallization in shallow basins. The resulting brine (bittern) contains high concentrations of valuable elements. The project will develop sustainable and cost-effective technologies that will contribute to securing European access to CRMs through a circular processing of the abundant bittern resources.

The consortium brings together leading experts from academia and industry to:
• Develop 3 innovative technologies to target the extraction of Magnesium (Mg), Lithium (Li) and other trace-elements (Rb, Sr, Cs, Ga, Ge, Co, B).
• Establish multiple auxiliary processes to provide full circularity during the production process.
• Produce the required energy from salinity gradient power.
• Generate modelling tools for simulation, sizing and evaluation of the processes to ensure optimal use of the resource for given framework conditions.
• Characterise and map bittern availability in Europe and the whole Mediterranean basin.
• Demonstrate the impact of coupling desalination with saltworks for cogeneration of freshwater and salt.
• Pave the way for further development, ensuring wide adoption and acceptance.
Mapping and Characterisation of Bittern Availability in the Mediterranean Basin: We've interacted with numerous saltworks and analysed bittern samples from 30 locations, giving us a sounds basis for wide application of our results in the future.

Our results show potential for more than 50% increase in saltwork productivity when integrating them with desalination and feeding the brine to them.

The Real Environmental Laboratory has been set upin Trapani (Italy), using a building already present inside the ancient saltworks, to house a laboratory that allows to conduct bittern characterization analysis directly on site.

Magnesium Recovery: We' have achieved 100% recovery of the Mg present in the bitterns with over 99% purity of the recovered mineral. The crystalliser design has been optimised and the pilot plant has been constructed and is being tested.

Lithium Recovery: Our newly developed Li-selective membranes meet most target specs at lower production costs. A pilot plant has been developed both for the Li separation and for the Li crystallisation and is now being tested.

Trace Elements Recovery: We've identified promising sorbents for various elements`(B, Sr, Co, Ga and Ge) and developed new ones for Cs and Rb separation. Test with sorption columns and cycling operation are being performed in order to evaluate also the scalability of the system and to better characterise the optimal desorption/regeneration conditions.

Auxiliary Equipment: We've explored the optimal conditions for acid/base production via ElectroDialysis with Bipolar Membranes and energy production from bittern via Reverse ElectroDialysis. Several pre and post-concentration technologies have been tested and chosen, with a pilot scale osmotic membrane distillation unit, a mechanical vapor compression pilot and a diffusion dialysis pilot unit now built.

Integration of Technologies: We're adapting auxiliary technologies for optimising species-specific separation layout. Final process scheming are defined with ongoing work on diagrams, control strategies, and equipment layout.

Development of Multi-Scale Modelling Tools: We've created and validated multi-scale modelling tools compared against experimental data. A simulation platform integrating these tools enables analysis and optimisation of the SEArcularMINE prototype system.

Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) studies have been performed identifying the hotspots and informing the development process.
Progress Beyond State of the Art

In our efforts to advance beyond the current state of the art, we're making strides in several key areas:

Magnesium Crystallisation: We're employing cutting-edge modelling techniques and tools to revolutionise the crystallisation process of Magnesium Hydroxide, which is leading us towards the creation of an innovative Magnesium crystallization unit (Mg-CGCR).

Lithium Separator: We're on track to develop high-performing, cost-effective Lithium membranes, a significant improvement over existing market offerings. We're also constructing a unique Lithium-selective electro-membrane device (Li-MFCDI) for testing these breakthroughs.

Trace Element Recovery from Seawater: With novel, highly selective sorbents, we've achieved continuous extraction of trace elements from seawater, a process now under bench-scale tests, with plans for pilot scale tests in the project's next phase.

Closed Loop Circular Process: We're pioneering auxiliary technologies for concentrating and separating solutions, and generating chemicals and energy in-situ, with the goal of realising a circular, self-sustaining system using saltwork bitterns.

Expected Results

Our project's anticipated outcomes include prototyping and patenting a range of innovative technologies, such as a Magnesium Crystalliser, lithium selective membranes and separation cell, and a trace element recovery unit. We also expect to commercialise integrated water desalination processes with saltworks and an innovative waste-stream valorisation process - the SEArcularMINE.

Expected Impacts

The SEArcularMINE circular process aims to bolster sustainable access to vital trace elements like Mg and Li within the EU, advance a clean, low carbon economy, and unlock significant reserves of underused resources. This environmentally conscious approach, leveraging only seawater and eliminating the need for external chemicals, will significantly reduce the demand for energy and freshwater. Furthermore, our technology aims to mitigate freshwater scarcity cost-effectively by incorporating seawater desalination.
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