Colloidal mills (rotor–stator type) are primarily employed for which level of grinding/dispersing service in liquids?

Introduction / Context:
Colloidal mills are high-shear rotor–stator devices used to reduce droplet/particle size in suspensions and emulsions. They complement homogenizers and high-shear mixers in the wet processing toolkit.

Concept / Approach:
The narrow gap and high tip speed create intense shear and turbulence that break droplets/agglomerates down to fine sizes (often a few microms). However, they are not designed to produce dry, sub-micron powders (that role belongs to jet mills or media mills). For liquid systems, “fine” is the correct level—smaller than intermediate dispersers, but not truly ultrafine dry comminution.

Step-by-Step Solution:
Identify mechanism: liquid-phase high shear.Relate achievable sizes: fine dispersions in the low-microm range.Select “Fine”.

Why Other Options Are Wrong:
Coarse/Intermediate: understate the shear capability.Ultrafine: refers to dry micronization; not the typical domain of colloid mills.

Final Answer:
Fine