Skip to main content

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

Periodic Reporting for period 1 - SEArcularMINE (Circular Processing of Seawater Brines from Saltworks for Recovery of Valuable Raw Materials)

Reporting period: 2020-06-01 to 2021-11-30

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.

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 and on-site solar and wind energy.
• 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.
• Pave the way for further development, ensuring wide adoption and acceptance.
More than 20 different saltworks have been engaged and bittern samples were collected from 18 different sites and thoroughly characterised.
A survey campaign collected information on the amount and variability of recoverable minerals within Saltwork bitterns across the Mediterranean and consulted on the viability and stakeholder interest of integrating desalination processes to the SEArcularMINE approach - highly desirable in many areas affected by water scarcity, where saltworks are often located.
Results show that when integrated with RO desalination saltworks productivity could be enhanced up to 50%.

Novel and valuable information on crystallisation kinetics has been gathered.
Preliminary laboratory tests with real bitterns from different areas of the Trapani saltworks, have shown that the SEArcularMINE approach can lead to 100% recovery of Mg with purity above 99%.
These recovery values are to be validated and optimised in the Magnesium Crystalliser prototype to be constructed and tested in the second phase of the project.

Novel Li-selective membranes have been designed and prepared, with significantly lower production costs, reaching already most of the target fluxes and selectivity rate specifications.
Laboratory tests have demonstrated that Li2CO3 at high purity can be recovered with high efficiency (up to 80%).

A first selection of most promising sorbents for B, Sr, Co, Ga and Ge has been accomplished and novel sorbents have been developed for the difficult separation of Cs and Rb.
Sorption attainment times were demonstrated to reach the target values of 15 and 20 minutes for most elements.
Testing has demonstrated that most separated trace elements can be recovered in mineral form at high purity by precipitation of crystals.

Adaptation to SEArcularMINE conditions has been accomplished for a number of auxiliary technologies for solutions concentration and for in-situ generation of chemicals and energy. Partners are engaged with a joint endeavour to optimise the layout of species-specific separation throughout the process, maximising the performance of the whole integrated cycle.

Advanced multi-scale modelling tools were developed in parallel, being thoroughly validated via comparison with experimental data, for each of the core and auxiliary technology.
A simulation platform will integrate all modelling tools to enable the simulation, analysis and optimisation for the SEArcularMINE integrated prototype system.
New knowledge, new modelling approaches and computer-based tools are being created to understand the complex crystallisation processes of Magnesium Hydroxide - potentially providing the base for further developments in crystallization industry for fine chemicals and bulk materials and paving the road for the development of an innovative Magnesium crystallization unit (Mg-CGCR).
Innovative Lithium membranes will be developed with optimised performance and significantly lower costs than the market leading ceramic membranes currently available. A novel Li-selective electro-membrane device (Li-MFCDI) will be constructed and tested to proof the competitiveness of novel membranes and flowing-carbon electrodes concept.
Highly selective sorbents and novel materials have been identified and produced. For the first time, bench-scale tests have been performed for continuous selective-extraction of TEs from seawater brines, to be proved in the second phase of the project at the pilot scale.
Progresses beyond the state-of-the art are being recorded for a number of auxiliary technologies for solutions concentration and separation (e.g. osmotic-MD and FO, RE-MVC) and for in-situ generation of chemicals (EDBM) and energy (RED). We aim to be the first to demonstrate, at pilot scale, the use of saltwork bitterns to produce all the chemicals needed (NaOH, HCl) within the circular system for our innovative mineral extraction processes.

Prototype novel Magnesium Crystalliser (licensing and/or commercialisation)
Novel lithium selective membranes (patent)
Novel lithium separation cell (patent)
Prototype novel Lithium separator device (patent/licensing)
Novel trace element selective sorbents (patent)
Prototype novel trace element recovery unit (licensing)
Novel process for in-situ generation of reactants (patent)
Viable integration of water desalination to saltworks (commercialisation)
SEArcularMINE innovative waste-stream valorisation process (licensing and/or commercialisation)

SEArcularMINE’s circular process concept will contribute to the following impacts:
• Secure sustainable access to Mg, Li and other trace elements within the EU.
• Support the transition to a clean, low carbon economy via advanced technological development reliant on CRM access.
• Create a technology base for radical innovations to unlock substantial reserves of new or currently unexploited resources within the EU.
• Present an alternative to the high environmental costs of current extraction of finite global reserves, through a circular process which uses only seawater as an input, eliminates any requirements for external chemicals and strives to bring the demand for energy and freshwater close to zero.
• Mitigate freshwater scarcity at low cost by trialling the integration of the technologies with seawater desalination