Project duration: 1 January 2021 – 31 December 2023


RFC-Upscaling proposes the Reflux Flotation Cell (RFC) technology for mineral processing companies, with ROI in 3 – 4 years. Within the project, it is planned to commercialise the technology as a new product of FLSmidth for copper and iron ore. The RFC requires 30 % less capex and 20 % less opex compared to the existing flotation technologies. The new design allows higher throughputs, a broader particle size distribution and recovery of finer particles.

The solution (technology)

Mineral-bearing ores are mined and processed on a large scale. During the processing, the rocks are milled and crushed into much smaller particles that contain the mineral fractions in a certain concentration. Milling yields particles with valuable mineral components as well as a waste fraction with gangue particles. These need to be separated from each other for further processing of the valuable, mineral-bearing fraction – where the gangue fraction that is currently of no economic value is discarded in tailings. The key technology for the valuable-gangue particle separation in the process chain is flotation. In large tanks that are mostly operated in series, air bubbles rise from the bottom to the top. If the chemical milieu is appropriate, hydrophobic particles (e.g. copper sulfide) attach to these rising air bubbles and form a froth layer at the top, which is constantly removed. Hydrophillic particles (e.g. silica) sink and leave the tank with the liquid at the bottom. The performance in terms of throughput of current technologies is limited in two ways: on the one hand through gas bubbles that leave the tank at the bottom, and on the other hand through too much liquid that leaves the tank together with the froth at the top. The novel Reflux Flotation Cell (RFC) technology avoids both problems with an entirely new internal design which results in much higher throughputs whilst simultaneously separating smaller particles in a more efficient method that improves gas bubble control. Consequently, flotation cells can be much smaller for given separation tasks and/or a much lower number of tanks are needed to operate in series (one or two tanks only). The RFC has been successfully demonstrated at TRL 5 at FLSmidth A/S, (DK) together with KGHM (PL) for copper ore particles, where ore samples have been shipped to the lab facilities of FLSmidth for testing. The preliminary results from the pilot-scale studies indicate that the RFC technology can help mines to save up to 30 % capital investments and use 20 % less water and energy. Within the project, the RFC technology will be scaled up to TRL 7 – 8 (depending on the application) and demonstrated in the field at a copper ore mine (KGHM) and at an iron ore mine at LKAB. It is our goal to commercialise the RFC technology during the three-year project through sales of full-scale plants at TRL 9, for example, with our partners KGHM, PL and LKAB, SE. This will take place if the demonstrations prove that a return on investment is possible in 3 – 5 years and that environmental impacts are lowered.


  • Helmholtz-Zentrum Dresden-Rossendorf e.V. (HZDR), Germany
  • IVL Swedish Environmental Research lnstitute, Sweden
  • KGHM Polska Miedz Spólka Akcyjna, Poland
  • Luossavaara-Kiirunavaara AB (LKAB), Sweden
  • Norwegian University of Science and Technology (NTNU), Norway
  • FLSmidth & Co. A/S (Lead Partner), Denmark