MagNa: Recovering valuable raw materials from seawater

Seawater desalination is an increasingly used method for obtaining water for industrial uses, but this process generates brines, effluents with a high concentration of salts, which have traditionally been considered waste. The MagNa project (Valorising Brine into a Sustainable Resource through Mg(OH)2 and NaCl recovery), will valorise brines by recovering high-purity magnesium hydroxide and sodium chloride –salt– thanks to an innovative technology.

Magnesium hydroxide and sodium chloride are valuable raw materials with applications in different industries such as chemicals and pharmaceuticals, and are currently imported in a large percentage from countries outside the European Union (EU). In this context, the MagNa project aims to reduce this dependence and, at the same time, minimise the environmental impact of desalination through a circular economy approach.

Within the framework of the project, an innovative industrial-scale brine treatment train is being developed at the facilities of Aitasa (Aigües Industrials de Tarragona Societat Anònima) to recover high-purity magnesium and sodium. This train, which will have two differentiated units, will treat an approximate flow of 6.5 cubic metres/hour of seawater.

The contribution of the UPC team, through the Resource Recovery and Environmental Management (R2EM) group of the Barcelona Research Center in Multiscale Science and Engineering (CCEM), focuses on recovering magnesium from desalination brines to produce Mg(OH)₂(s) through reactive crystallisation. The product obtained has the required quality for commercialisation in pharmaceutical applications, in fertiliser formulation and as a flame retardant.

The process is based on a circular approach, in which the reagents required for the production of Mg(OH)₂(s) are generated on-site from the resulting salt and through electrochemical membrane technologies.

MagNa will help address two major challenges for Europe: vulnerability to the lack of local production of key raw materials for economic development, and the management of the growing presence of brines, especially in Spain, which is one of the five countries in the world where water is most heavily desalinated due to its water stress context. In addition, the technology to be created can be replicated in other desalination plants, maximising its medium-term impact.

Consortium, Budget and Funding

The project is led by Cetaqua-Centre Tecnològic de l'Aigua and, in addition to the UPC, includes the participation of Aitasa-Aigües Industrials de Tarragona and Seureca Veolia. MagNa is co-funded by the EU EIT RawMaterials call (under the Horizon Europe 2021-2027 programme). It has a budget of €2,540,331 and a duration of 2 years and 6 months (September 2025 - March 2028).