Differential flotation kinetics of copper sulfide and molybdenite using nitrogen nanobubbles

This study investigates the effect of nitrogen nanobubbles on the kinetics of copper sulfide minerals and molybdenite flotation. Experiments were conducted on a mixed copper sulfide–molybdenite ore, a copper sulfide concentrate, and a molybdenite concentrate using plain water and nitrogen nanobubble-containing water. Aeration was performed using either air or nitrogen to generate conventional bubbles. The obtained data were fitted on five first-order kinetic models. All three feed types exhibited a strong correlation with first-order kinetic models, particularly the classical first-order model, with correlation coefficients exceeding 0.98 in all experiments. For the mixed feed, the highest kinetic constant for molybdenite recovery (0.061 min−1) was obtained in the presence of nitrogen nanobubbles with nitrogen aeration, whereas the highest kinetic constant for copper sulfide recovery (0.019 min−1) occurred using plain water with air aeration. Regarding the molybdenite concentrate, the highest kinetic constants for molybdenite (0.073 min−1) and copper sulfide (0.12 min−1) were obtained when nanobubble-containing water was used with air aeration. In the copper sulfide concentrate flotation experiments, the highest kinetic constant for molybdenite recovery (0.155 min−1) was achieved using nanobubble-containing water and nitrogen aeration, whereas the highest kinetic constant for copper sulfide recovery (0.020 min−1) was obtained when nanobubble-containing water was used with air aeration. Overall, the results demonstrate that the presence of nitrogen nanobubbles in water, as well as the use of nitrogen gas instead of air for generating conventional bubbles, improves the flotation kinetics of molybdenite and promotes its selective separation from copper sulfide minerals.