Technical feasibility assessment of copper recovery from sulphide flotation tailings through process optimisation and flotation

Reprocessing copper sulphide tailings offers a chance to recover residual metals and reduce environmental liabilities; however, conventional flotation cells often struggle to process such fine, mineralogically complex ores. This study evaluates the technical feasibility and performance limits of conventional flotation for extracting copper from rougher–scavenger tailings. Two sequential approaches were tested: (i) reagent-assisted rougher flotation of the as-received tailings and (ii) a desliming–regrinding–flotation process designed to improve liberation and flotation recovery. Response Surface Methodology (RSM) with a Box–Behnken design was employed to optimise collector dosage, frother concentration, and air-flow rate. The quadratic model fitted (R 2 = 94.75 %) predicted a maximum verified recovery of 53 % Cu under optimal reagent conditions. Beyond this point, recovery plateaued, indicating that further improvement was constrained by multiple factors, including incomplete mineral liberation, particle-size effects, and flotation conditions . Desliming, followed by stirred-mill regrinding to P 80 ≈ 38 µm, significantly enhanced recovery, confirming that liberation of middling particles was essential for further gains. Nonetheless, grinding finer than 20 µm increased gangue entrainment and lowered concentrate grades, consistent with Trahar’s size-dependent flotation model. The findings therefore define the experimentally observed performance boundaries of the investigated conventional flotation route and identify the additional surface characterisation, process optimisation and scale-up requirements needed before an industrial tailings-reprocessing flowsheet can be established.