Gravity separation is one of the ancient technologies for mineral processing and is still in widespread use. In recent years, many kinds of machinery for wet gravity separation have been developed and applied to process fine particles and solid waste.
The authors have reviewed newly developed machineries, in addition to the principle of wet gravity separation and conventional machineries. Most of them are conducted in gravitational fields or films of flowing water. The former harnesses the settling behavior of particles in water and the later the movement of particles in films of flowing water. The principles of these two methods and their state of application for commercial plants are detailed.
In gravitational field, Batac (TACUB) jig is a cost-efficient separator and provides better performance than Baum jig in coal preparation, where feed size is 0.5-200mm. Modified jigs are being developed to separate larger or smaller feed. The Wilfley table and Reichert cone are described as major machineries of film-flowing concentration.
Some centrifugal gravity concentrators have been developed because of the applicability of gravity separation to fine particles. A comparative review of typical centrifuge-type gravity concentrators is presented herein.
Two recycling plants using the TACUB jig are mentioned. One plant is processing waste concrete at 600,000 tons/year, and coarse aggregates are recovered and reused. The other plant was built to demonstrate that jig separator is efficient to separate and recover valuable plastics from scrapped office automation equipments.