This application in an IBC container will be difficult for both the container and the mixer.  Dissolving 17% of 70 Pa s fluid and 26% of 250 Pa s in a water-like (0.001 Pa s) fluid will be difficult.  Dissolving or dispersing any 250 Pa s material in even a good solvent having only a 0.001 Pa s viscosity will take considerable time, potentially on the order of hours.  The final viscosity is unspecified, so a final viscosity of 1 Pa s has been assumed in sizing the mixer.
Assuming 50 hz power, a typical direct drive (motor speed) mixer will run at about 1,500 rpm.  (60 Hz power will change both the speed and impeller diameter.)  A 20 cm diameter propeller or hydrofoil impeller (pumping downward, obviously) is recommended for 1,500 rpm and will require a 2.25 kW motor.  A gear reduced mixer typically will run at 255 rpm using a 32 cm diameter propeller or hydrofoil impeller and a 1.12 kW motor.  The gear reduced mixer is recommended.
Modifications to the IBC container would include a top opening large enough to insert the impeller.  That opening should not be used for adding ingredients, because contact with the rotating shaft will be a dangerous safety problem.  The IBC tote should be firmly attached to the floor, so it does not move or turn.  The mounting for the mixer needs to be strong and rigid.  The IBC container must be made of stainless steel.  A polymer liner in a cage container will be unsafe with any mixing intensity.  The liner could be drawn into the mixer damaging both the container and the mixer.  A variable speed drive would be a good option to control splashing as ingredients are added or as the container is emptied.

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