GlobeCore does offer calcium carbonate grinding and dispersion using its AVS / AVSp vortex layer technology, which is shown in their videos for fine and nano-scale processing. However, achieving a guaranteed D90 = 200-300 nm is not a standard specification and strongly depends on the process setup: wet operation, use of dispersants, multiple passes in recirculation mode, cooling, and PSD measurement method. For nano-range targets, GlobeCore typically recommends AVSp units for lab/pilot trials, followed by industrial AVS units once the recipe is proven.