Introduction
Gravity separation, also known as sediment-preferential flotation, is a physical method used to separate fine particles of different compositions by applying a force, usually gravity, to light particles. By utilizing the differences in specific gravity of the particles, the heavier particles sink, while the lighter particles remain on the surface of the slurry. This separation technique is simultaneously used with other methods to separate components of mixtures.
The primary application of gravity separation method is for concentration of mineral ore deposits. Gravity separation is most effective when the differences in the specific gravity of the particles to be separated is most prominent. Commonly used techniques include hand panning, sluices and jigs. As gravity separation depends upon the size and density of the particle, its efficiency becomes greater when the size of the particles becomes closer and the density becomes further apart.
Gravity separation is usually employed in situations where the target material has a low density and different specific gravity value in comparison to the medium used for the process. Different mediums available include air, water, fuel (e.g. diesel) and other mediums. Usually, areas with higher gravities are preferred for its utilization. In a typical gravity separation process, material is suspended in a liquid medium and is then subjected to a precise Force that acts in a rectilinear direction. Vortex generators, spirals and cones are used to reduce sedimentation time, whereas raking machines and slush pumps are used in the main beneficiation process.
Gravity separation is primarily associated with the recovery of precious metals for the purpose of depaparization. This is done by intensifying the centrifugal force cells that keep the precious metals in suspension. As the particles which are heavy relative to the liquid medium are subject to a more intense centrifugal force, their settling speed is higher and eventually their deposition rate becomes faster than that of the light particles.
Gravity separation is also important for effective removing of suspended particles and sediments form water. Sedimentation tanks and settling basins are known to be the most common methods employed to retain such fine-grained suspended materials. These are most beneficial factors that keeps beneficial suspended particles such as fossil nutrients’ plankton, bacteria and other associated organisms.
Gravity separation is also used in other industries, such as aerospace and mining. In mining, the ore is separated by using dense mediums, centrifugal force and sometimes other eqipment and procedure. In aerospace, gravity separation is applied primarily for the recovery of fuel fuel.
Conclusion
Gravity separation is an important procedure in the recovery of precious metals and concentration of mineral deposits. As a result, it is an economic and effective method for the recovery of fine particles of different compositions. Gravity separation is also helpful in the removal of suspended particles from wastewater and, in aerospace, it is used for fuel recovery. With an array of methods, however, gravity separation has a large range of industry applications and is used extensively for their efficient resource recovery.
