What rotor speed and gap settings in a colloid mill determine final bitumen emulsion particle size?

Particle size is controlled by the tip speed of the rotor and the rotor-stator gap, plus flow rate and viscosity. Higher rotor speed and smaller gap increase shear and generally reduce droplet size, but too aggressive settings can overheat the emulsion and reduce stability. Throughput also matters, because higher flow shortens residence time and can raise particle size. Plants tune speed and gap for each grade, then lock settings with QA checks so the same PSD is reproduced batch to batch under consistent temperatures.