During the first phase of the project, the consortium achieved significant progress in scientific research, technological validation and stakeholder engagement.
Phosphogypsum samples were collected from the project’s case studies and analysed to determine their chemical composition, mineralogical structure and radiological properties. A total of 6 locations were characterised, generating a comprehensive dataset that supports the development of safe and efficient valorisation strategies.
Two chemical recovery routes were investigated to convert phosphogypsum into valuable industrial products. Laboratory-scale experiments demonstrated the technical feasibility of producing compounds such as sodium sulphate, ammonium sulphate and calcium-based materials. Industrial partners defined target product specifications to ensure compatibility with potential applications. For example, sodium sulphate is expected to reach purities above 99.5% for applications in detergents, paper production and construction materials, while ammonium sulphate requires purities above 99% with strict control of metallic impurities (e.g. iron and lead below about 5–10 ppm). Experimental work focuses on optimising the processes to approach these quality levels while maintaining suitable particle size and moisture content, with preliminary purities around 90% depending on the product.
The project is also investigating other materials such as precipitated calcium carbonate and katoite for potential use in cementitious materials, where purity requirements are less restrictive. Preliminary work is also exploring the recovery of phosphorus and rare earth elements from phosphogypsum residues through leaching experiments using different solvents, including hydrochloric acid, sulphuric acid, citric acid and ammonium-based solutions. Results showed that acidic conditions significantly enhance the dissolution of both calcium and phosphorus, although co-dissolution limits selective separation and further optimisation is required. Rare earth elements such as yttrium, lanthanum, neodymium and cerium were detected in leachate solutions and will be investigated further for potential recovery.
Engineering activities were initiated to prepare the construction and operation of a mobile pilot plant. During this period, the consortium completed the conceptual and preliminary engineering design of the sodium hydroxide-based process, including process flow diagrams, mass and energy balances and equipment specifications.
Recovered materials are currently being evaluated for industrial applications in sectors including detergents, construction materials, paper manufacturing, fertilisers and battery technologies. Initial testing by industrial partners indicates that some recovered products already meet relevant quality specifications.
Stakeholder engagement activities were also conducted to better understand societal perceptions regarding phosphogypsum management. The project mapped around 300 relevant stakeholders, including industrial operators, regional authorities, environmental organisations and local communities near phosphogypsum stacks. In addition, two citizen workshops (North Macedonia and Portugal) were organised to promote dialogue and transparency.
The main expected outcomes include pilot-scale demonstration of phosphogypsum valorisation processes, the production of market-ready secondary raw materials and the development of circular business models supporting large-scale deployment. These outcomes are expected to reduce industrial waste accumulation, improve resource efficiency and strengthen the supply of strategic raw materials in Europe.
