• Different frothers of varying strength and composition have been compared in the RFC. • MIBC produced finer bubbles and superior flotation recovery in hypersaline water compared to other frothers. • Medium‑strength frother in hypersaline water showed no recovery gain but reduced entrainment versus tap water. • Changes in recovery and grade were outcomes of entrainment driven hydrodynamics intrinsic to the RFC’s design. Frother selection in conventional flotation is strongly influenced by bubble structure and froth transport; however, the Reflux Flotation Cell (RFC) operates without a distinct froth layer and separates minerals primarily through bubbly‑zone hydrodynamics. This study therefore examined the effects of frother strength and hypersaline water, two factors that modify bubble coalescence and liquid carryover, on pentlandite flotation in the RFC. Results showed that both frother strength and concentration significantly affected the recovery of pentlandite and associated gangue minerals (primarily pyrrhotite). Increasing frother strength improved pentlandite recovery but also elevated pyrrhotite entrainment due to higher water recovery, resulting in lower enrichment ratios. Although weaker frothers produced smaller bubbles, the particle size distributions of the concentrates were similar across all frothers tested, with 35% of the recovered particles finer than 20 µm. Under hypersaline conditions, Methyl Isobutyl Carbinol (MIBC) achieved 49% pentlandite recovery at an enrichment ratio of 1.30, outperforming stronger frothers whose higher recoveries were accompanied by greater gangue carryover/recovery. Overall, the findings demonstrate that frothers in the RFC act primarily through hydrodynamic modification of bubble size, gas holdup, and water transport, consistent with the froth‑less separation environment of the RFC.
Ayedzi et al. (Thu,) studied this question.