First Insights into Scale-Up Procedures for Reactor–Separator Flotation Cells

Although several laboratory- to semi-pilot-scale reactor–separator flotation units have recently been developed and manufactured by leading companies, substantial gaps remain in the understanding of their scale-up procedures. To this end, the current study identifies the advantages and constraints of the classical retention time-based approach, standard dilution tests, and the McCabe–Thiele diagram. The results revealed that the traditionally used retention-time-based flotation kinetic and/or its modified version scale-up approaches cannot be adapted to reactor–separator flotation cells, mainly due to differences in dispersion regime, conditioning tank, slurry volume, feed flowrate and the role of circulating load. Therefore, the number of passes at laboratory scale is proposed as a more appropriate scale-up parameter than flotation time for pneumatic flotation cells. The analysis suggests that a scale-up factor of 1 may be acceptable only when the conditioning tank, aerator, and separator collectively exhibit a plug-flow dispersion regime. A few uncertainties were discussed in detail in terms of utilizing standard dilution cleaner tests. A new flow diagram was proposed with respect to the integration of pneumatic cells with a particular focus on Imhoflot™ cell technology into existing concentration plants and the path toward test programs for greenfield projects. The presented case study demonstrated an alignment between the laboratory mechanical flotation kinetic test and the onsite lab/semi-pilot V-03 Imhoflot™ cell performance, providing a high degree of confidence in the proposed flowsheet. The selected 4xH Imhoflot™ cell configuration was well-suited to meet the projected industrial mass balance and product specifications.