Hydrophobic Flocculation of Coal Particles Controlled by Mechanical Stirring

The effects of mechanical energy input amount and input mode on the hydrophobic flocculation of coal particles in the stirring field were studied. Based on dimensional analysis, it was proved that the mechanical stirring speed can be used as the kinetic index of hydrophobic flocculation, and the mathematical expressions of floc formation and mechanical energy input were derived. Combined with the flotation tests, it was confirmed that the increase in stirring speed significantly promoted the hydrophobic flocculation of coal particles in a limited way. The full baffle stirred tank and three types of agitators, namely blade agitator, propeller agitator, and turbine agitator, were designed and manufactured. The turbulent kinetic energy and velocity distribution near the agitator were analyzed by fluid simulation, which showed that the axial flow field in the stirred tank was more conducive to the occurrence of flocculation.