Hydrocyclone

A classification device that separates particles by size and density using centrifugal force generated by tangential feed of a slurry into a cylindrical-conical vessel — no moving parts, making it robust and maintenance-efficient. The feed slurry enters tangentially at high velocity, creating a vortex. Centrifugal force (300-2,000x gravity depending on diameter) drives coarse/heavy particles outward and downward through the underflow (apex/spigot) while fine/light particles are carried inward and upward through the overflow (vortex finder). Cut size (d50): the particle size at which 50% reports to each product — typically 5-150 μm, controlled by cyclone diameter, feed pressure, apex/vortex finder sizes, and slurry properties. Cyclone diameters: 25 mm (lab/fine classification) to 1,500 mm (primary grinding circuit). Wear components: rubber-lined body and vortex finder (NR 40-55 Shore A for impact zones), polyurethane apex and vortex finder (for fine abrasion zones), and ceramic inserts (for extreme wear). Brands: Metso Outotec (CAVEX — involute feed design), Weir Minerals (Krebs), FLSmidth, and Eral. Applications: grinding circuit classification, thickener feed, desliming, and dewatering. Per cyclone manufacturer performance models (typically empirical Plitt or Lynch-Rao models).