"Hydrocyclone separation of polymetallic nodules from surrounding water and sediment in deep-sea mining operations"

Growing populations, high-technology applications and the energy transition raise the demand for rare earth elements. As a secure supply in the future is all but certain, opportunities arise for deep-sea mining. Polymetallic nodulesthat are located on the vast, sediment-covered ocean floors, are one of the more promising deep-sea mineral occurrences. Large amounts of unwanted surrounding water and sediment are collected along with the nodules in theharvesting process. Separating the sediment and excessive water from the nodules before transportation toward the surface could mitigate sediment plumes and be beneficial for energy consumption. In this research, the feasibility of a hydrocyclone inspired machine is investigated for this process. With model experimentation, the key performance parameters are studied using varying particle fractions, adjusting split ratio and conical angle. Timescale ratios areused for particle scaling, and to describe their behaviour. The cyclones’ separation shows great potential. However, large particles can be problematic, and the energy consumption is too high for deep-sea operation. Therefore, topside utilisation is recommended.Keywords: Polymetallic nodules, separation, hydrocylone, performance parameters, topside.Offshore and Dredging Engineerin