This type of application is usually handled with a high-speed disperser mixer.  The impeller is usually a saw-tooth disk impeller running at a high speed, 1,000 rpm (17 rps).  The recommended impeller diameter is 0.33 m driven by a 25 kW motor.  Most such mixers have a hydraulic raising and lowering system to access the vessel and move the impeller location vertically to ensure complete mixing.  Such mixers also have a variable speed drive to avoid splashing as the temperature increases and the viscosity decreases.