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

In this proposal, we build on the ancient and still widely used process of saltworks, where seawater goes through natural evaporation and fractionated crystallization in shallow basins. This process produces sea salt and a brine (bittern) free of calcium as a by-product, which is 20 to 40 times more concentrated than seawater in some crucial elements. The SEArcularMINE project uses this bittern, targeting Magnesium, Lithium and other Trace-Elements belonging to the alkaline/alkaline earths metals (e.g. Rb, Cs, Sr) or transition/post-transition metals (e.g. Co, Ga, Ge) group. Three innovative technologies will be developed and integrated within a circular approach, based on three different processes: 1) reactive crystallisation; 2) selective membrane separation; 3) selective sorption/desorption. The concept is enhanced by: i) energy-efficient concentration steps, ii) on-site generation of reactants from the available brines and iii) production of the required energy from reverse electrodialysis fed with the process outlet brine on-site and solar or wind energy. A multi-disciplinary approach will be adopted for bringing the low TRL of the three main technologies and of the overall integrated concept up to TRL4-5. There will be fundamental advances in the knowledge of the processes, leading to break-through developments of the 3 most important technologies for the recovery of minerals from brines, but also from seawater or any other kind of metals-rich solution. Within our circular strategy, we will look also at the option of including desalination upstream from the saltworks, providing freshwater to the local communities and a concentrated stream to feed the saltworks, increasing salt productivity and bittern availability. The adopted approach will have positive effects on the environmental and financial performance, laying the foundations for a future industrial application.