Aggregation of ultra-fine scheelite particles induced by hydrodynamic cavitation

Hydrodynamic cavitation enhanced ultra-fine particles flotation could be mainly due to the generation of nanobubbles in the process of cavitation, and their role in bridging particles to form aggregates. In this paper, the aggregation behavior of ultra-fine scheelite particles induced by hydrodynamic cavitation was investigated. Investigation was carried out through flotation tests, zeta potential measurements, turbidity determination and microscopic imaging. The results of flotation tests confirm that hydrodynamic cavitation can enhance the ultra-fine scheelite particles aggregation and their flotation. Nanobubbles generated by cavitation make the solid particles less negatively charged, thereby reducing the repulsive force between particles. With a low sodium oleate (NaOl) concentration, particle aggregates start to form in the slurry treated by hydrodynamic cavitation, while few aggregates are generated in the slurry without cavitation treatment. As NaOl concentration increases in the slurry pre-treated by cavitation, the formation of a network structure consisting of hydrophobized mineral particles, conventional bubbles and nanobubbles enhances the flotation recovery of ultra-fine scheelite particles.