Hydrocyclones, or more simply Cyclones, and variations such as McLanahan Separators™ are used in a variety of applications including classification, desliming, fines recovery, densifying and dewatering.
They can be used in industries such as sand, aggregates, coal, industrial minerals, hard rock mining and more. Hydrocyclones have become widely used in mineral processing because they are relatively inexpensive, process high volumes, take up minimal floor space and have no moving parts.
Hydrocyclones are typically a cono-cylindrical shape with either a tangential or involute feed inlet configuration. Slurry enters the feed inlet at a designated pressure and volume. Independent of the shape or configuration of the inlet, slurry follows the fall of the upper cylinder, resulting in a swirling action. Centrifugal forces send coarser material to the outer wall to travel downward and be further accelerated in the conical sections. These coarser fractions then exit through the apex, or spigot, at the bottom of the Hydrocyclone. Finer fractions remain rotating around with the fluid. The finer fractions are removed with the upward swirling flow through the vortex finder.
McLanahan has collected field data from hundreds of applications, allowing process engineers to make the accurate selection of size and configuration for each application using computer simulations. Performance is based on the configuration of the inlet area, vortex finder diameter, underflow and overflow diameters, cylindrical sections, and cone angle.
Hydrocyclones and Separators™ are exceptionally simple in design and have no moving parts. This, combined with a design that includes rubber-lined, bolt-together sections, makes this equipment safe and simple to operate. Alternative linings, such as polyurethanes and ceramics, are also available.
The McLanahan Separator™ is the original siphon-assisted or vacuum-assisted Hydrocyclone developed and patented more than 40 years ago. This development answered many issues that plagued Hydrocyclones, especially when used for stockpiling sand. This equipment is still a standard today for stockpiling and inter-stage processing where underflow density control is critical.
The Separator™ differs from a conventional Hydrocyclone in that a rubber underflow regulator, sometimes called a fishtail, is fitted to the apex and an overflow pipe of specific size and length is fitted to the overflow flange. The overflow pipe returns below the apex and creates a siphon that closes the regulator. An air valve is fitted to the overflow pipe and air is bled in to regulate the amount of siphon generated. This configuration allows consistent underflow density regardless of feed density, which in aggregate operations is a common occurrence. This benefits any moisture sensitive downstream process such as stockpiling and attritioning.