The agitation mixing process refers to in-tank batch mixing by way of propeller or turbine mixers. Props or turbines are multiple blade impellers that turn at various speeds to pump and circulate fluid inside a mixing vessel. An electric motor is typically used to rotate the mixer shaft at speeds from 100 rpm to 1750 rpm. The propeller pumps the fluid in a recirculation pattern in the vessel, subjecting the fluid to turbulence and disruption as it passes through the rotating elements. The fluid will also cavitate along the edges of the high-speed rotating elements.
Propeller mixers are used for both emulsification and dispersing. In the hierarchy of mixing, propeller agitation is the least effective and most time consuming method of creating suspensions and particularly emulsions. But it tends to be the easiest to incorporate, requiring the least amount of training, knowledge and experience.