Development and evaluation of the CAVEX dense medium cyclone

The CAVEX dense medium cyclone (DMC) was developed in the later part of the 1990s as a result of the expertise developed by Weir engineers in slurry pumping. The inlet area of the cyclone is designed to minimize turbulence and to reduce wear at the feed entry point, which provides more energy for particle separation at a given feed pressure. A parametric study was performed on a 150mm diameter unit to quantify separation efficiency as a function of feed pressure, apex diameter, medium density, and cone angle. The added energy in the cyclone was confirmed by comparing the stability of the medium in the CAVEX unit with that provided by a common commercial unit having the same dimensions. A 500mm unit was installed in parallel with an identically sized industrial unit in an operating preparation plant treating 12 × 1 mm coal. The separation efficiency values achieved by the CAVEX DMC were found to be higher than those obtained by the standard industrial unit and the amount of improvement increased with a decrease in particle size. The data from the pilot-scale and in-plant tests are presented and discussed in this article.