Challenges in Mixing of High Viscosity Materials

Challenges in Mixing of High Viscosity Materials

Materials  such  as  rubber,  polymer  and  putties  have  viscosity  exceeding  10 Pa-s.  These  materials   are  classified  as  high  viscosity  materials,  and  exhibit  characteristic  such  as  resistance  to  flow,  elasticity  and  non-Newtonian  behaviour.  Unlike  in  the  case  of  liquid  mixing,  flow  currents  do  not  get  formed  during  mixing  of  viscous  materials.  Mixing  is  therefore  achieved  by  mechanical  action,  shear  force  or  elongation  of  matrix  facilitated by  the  mixing  equipment. Mixing of viscous material necessitates dispersive mixing, distributive mixing and convective mixing mechanisms to occur in a system. Design and selection of mixing equipment for high viscosity applications, poses several challenges such as low flowability of material, poor heat transfer, scale up difficulties, high power and torque requirements. Mixers for high viscosity applications are built to overcome these challenges and therefore have some common characteristics. There are several different types of high viscosity mixers that are available for batch and / or continuous operations. The challenges associated with m