Where large samples (both in top size and weight) have to be examined it is not practical to use heavy liquids (being both expensive and time consuming). A laboratory heavy media separator may be used which simulates the action of a heavy liquid bath. Here is a schematically shows an Ericsson cone separator. Sized fractions of particles in the range of 6-50 mm.
The media passes up through cone A and overflows into cone B. Baskets are filled into the cylindrical sections of the cones and the feed put into cone A. The floats are carried up and over into the basket in cone B while the sinks remain in the basket in cone A.
A similar analysis to the laboratory heavy liquid analysis is performed, at several media S.G.’s and particle size ranges.