Study on the pulp conditioning effect of flotation under the synergistic action of jet and stirring

To investigate the influence of jet – stirring synergy on slurry conditioning in flotation, a geometric model of the jet device and driving impeller was established, and flow field simulations were conducted under different air-intake pipe diameters and impeller sizes. The effects of jet velocity and impeller speed on coal surface properties and flotation mineralization were further examined, and the applicability of the device to coals with different ash contents was verified. Results show that when the air-intake pipe diameter is 8 mm and the impeller occupies 67% radially and 50% axially of the mixing chamber, a composite flow field favorable for flotation is formed, ensuring efficient jet – impeller coupling. Increasing jet velocity and impeller speed reduces the number of fine particles adhering to the coal surface, increases the contact angle, enhances collector adsorption, and improves flotation mineralization. The optimal jet velocity and impeller speed are 7.00 m/s and 4 r/s, respectively. Compared with a conventional single-cell flotation machine, the jet – stirring synergistic flotation device significantly improves flotation efficiency, particularly for medium- and high-ash coals.