Gravity Concentration Tech
AUTHOR：Admin DATE：13-05-23 VIEWS：
Historically the earliest method used,particles can be classified based on their specific gravity. Air is the main fluid medium used for the process. Gravity concentration processes include:
Heavy media or dense media separation (these include, baths, drums, larcodems, dyana whirlpool separators, and dense medium cyclones)
Shaking tables, such as the Wilfley table
spiral separators
Reflux Classifier
Batac jigs
Centrifugal bowl concentrators, such as the Knelson concentrator
Jig concentrators are continuous processing gravity concentration devices using a pulsating fluidized bed.(RMS-Ross Corp. Circular jig Plants)
Multi gravity separators (Falcon, Knelson, Mozley and the Kelsey Jig)
Inline pressure Jigs
Reichert Cones
These processes can be classified as either dense medium separation or gravity separation. The difference between the two that gravity separation does not use a dense medium to operate, only water or air. Dense medium separation can be performed with a variety of mediums. These include, organic liquids, aqueous solutions, suspensions in water and suspensions in air. Of these, most industrial processes use suspensions in water. The organic liquids are not used due to their toxicity and difficulties in handling. The aqueous solution as a dense medium is used in coal processing in the form of a belknap wash and the suspension in air is used in water-deficient areas, like china, where sand is used to separate coal from the gangue minerals. The dense medium separation is also classified as absolute gravity separation as the sinks and the floats travel in different directions. The gravity separation is also called relative gravity separation as they separate particles due to their differences in the magnitude of the particle response to a driving force.
These processes can also be classified into multi-G and single G processes. The difference is the magnitude of the driving force for the separation. Multi-G processes allow the separation of fine particles to occur and these particles can be in the range of 10 to 50 micron. The single G process are only capable of processing particles that are greater than 80 micron in diameter.
Of the gravity separation processes, the spiral concentrators and circular jigs are two of the most economical due to their simplicity and use of space. They operate by flowing film separation and can either use washwater or be washwater-less. The washwater spirals separate particles more easily but can have issues with entrainment of gangue with the concentrate produced..
