Analysis of key mixing parameters in industrial Wemco mechanical flotation cells

Flotation performance in mechanical cells is strongly influenced by hydrodynamics. Hydrodynamics is driven by the action of the impeller which is responsible for mixing in the cell. This paper evaluates key mixing parameters in three industrial Wemco mechanical flotation cells (#144, #164, #190; 14.2, 28.3, 42.5 m3). Residence time distributions, circulation times, impeller pumping capacities, impeller Flow numbers and power intensities are presented. RTD studies are based on LiCl tracer measurements. RTD studies showed that the #190, #164 & #144 behave as 2.1-2.4, 1.2 and 1.0 tanks in series respectively. Circulation times for the #164 and #144 were much shorter than the #190. The #190 and #164 had the highest pumping capacities. Dimensionless Flow numbers varied from 0.12 to 0.22. Iron losses by entrainment of fine particles (<45 µm) were higher in the #164, due to the higher intensity of mixing.