A dispersion process relates to the mixing of powders and liquids. A powder once added to any liquid will either dissolve or need to be maintained in a suspension within the liquid. Many solids form agglomerates or clusters once introduced to a liquid phase and the larger the agglomerates the more likely the solid phase will settle out. Mixing energy helps break apart these agglomerates and disperse them into a solution so they are scattered throughout the liquid phase more uniformly without settling.
A high-pressure homogenizer dramatically changes the velocity of the slurry over short distance and this serves to tear agglomerates apart very effectively. Homogenizers in general will not reduce primary particle sizes. For this, you would investigate Colloid Mills to grind or crush individual solid particulates.