Density Separation

Density separation is based on the principle that different minerals and materials may have different densities. If multiple minerals with different densities are placed in a liquid with an intermediate density, it is possible to separate minerals based on their specific gravity. McLanahan produces two different types of equipment that perform density separation – Hydrosizers™™ and Flat-Bottom Classifiers™.

In each piece of equipment, feed enters from the top to eliminate turbulence and evenly distribute the feed. In a Hydrosizer™™, injection water enters through a set of pipes with nozzles at the base of the upper sorting chamber, while in the Flat-Bottom Classifier™, injection water enters via a false bottom to the tank through multiple, long-life, replaceable nozzles. As the solids settle in the upper sorting chamber, they are met by a rising current of water, causing a hydraulically fluidized (“teeter”) bed to form. Lighter, or smaller, particles discharge over a peripheral weir and collect in a launder. Coarser, or denser, particles report to the base of the teeter bed and discharge through underflow valves.

In both the Hydrosizer™™ and the Flat-Bottom Classifier™, the density of the teeter bed determines the cut point. A PLC control system measures the teeter bed density and maintains it at a set point by controlling the rate of underflow discharge. Click on the equipment below to learn more about McLanahan’s density separation solutions.