Project R-14077

Study on the recycling of CaF2 sludge (Research)

The ever-growing demand for raw materials makes Europe highly dependent on imports from China, especially in terms of critical raw materials such as rare earth elements (REEs) and fluorspar. In the framework of the circular economy, it is of great importance to research alternative sources of REE and fluorspar in industrial residues. Calcium fluoride sludge (CaF2) from the phosphate industry is a potential 'secondary source' of these critical raw materials. However, to be recycled in industrial applications as fluorspar, the removal of contaminants is required. In the case of REEs and (even) radionuclides (RNs), it can generate economic benefit to extract these materials from the sludges. This PhD will research the design of an integrated treatment solution to remove impurities from CaF2 and to extract REEs and RNs. This via a complete chemical and radiological characterization of the sludge samples. Based on these results, a pre-industrial flotation setup (at Amphos21) is modified and optimized for the integrated flotation/extraction study for the treatment of CaF2 sludge. A techno-economical study will provide constant feedback to the process design to obtain an economically feasible process. In addition, the REEs and RNs behavior during the conversion of phosphogypsum (PG) into CaF2 will also be studied to realize a treatment solution of PG and provide a solution for PG landfills worldwide. In this way significantly expand the economic potential of the designed approach.

01 October 2023 - 30 September 2027