The Cyclosizer

 

The Background

The Cyclosizer is a laboratory precision apparatus for the rapid and accurate determination of particle size distribution within the sub sieve range. Each machine is calibrated individually before it leaves the works and typically separates at around 40, 30, 20, 15 and 12 microns. The Cyclosizer was developed for the mining industry, and a feature of the Cyclosizer separation is that it returns the size fraction for assay or microscopic examination so that information on liberation sizes can be gathered. The operation of the Cyclosizer is robust so that although some operator skill is required, it is less sensitive than some other competing processes that do not produce size fractions for examination.

Particles are separated according to their Stokes equivalent diameter and in this sense differ from say mesh screen sizes, which rely on whether or not a grain will pass a square aperture. Thus when plotting the sizing results there is often a small inflection in the graph associated with the change in sizing principle. When a Cyclosizer sizing is plotted against sizings using other techniques, there is generally a small parallel shift for each technique that is a function of how the technique defines particle size.

Because the Cyclosizer uses the Stokes equivalent diameter, the fractions produced are specific gravity dependant. It is convention to express the sizings as quartz equivalents, but in reality, these sizings need to be corrected for variations in specific gravity. Corrections are calculated as part of the standard operating technique. Although a sizing may use an average specific gravity it is possible for discrete minerals to be classified separately. For instance in the first cyclone that separates at say 40 micron quartz equivalent this will also capture a 14 micron gold grain. Thus heavier minerals report to higher cyclones in the configuration.

Machine life depends on usage and the environment but it is not unusual for the working life to exceed 25 years.