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| '''Centrifugation''' is a mechanical separation process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The more dense components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Chemists and biologists may increase the effective gravitational force of the test tube so that the precipitate (pellet) will travel quickly and fully to the bottom of the tube.
| | Sieving is a simple technique for separating particles of different sizes. Coarse particles are separated or broken up by grinding against one another and the screen openings. Depending upon the types of particles to be separated, sieves with different types of holes are used. Sieving plays an important role in food industries where sieves (often vibrating) are used to prevent the contamination of the product by foreign bodies. The design of the industrial sieve is of primary importance here. |
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| ==Input== | | ==Input== |
| The centrifugation method is used to separate two miscible substances. The most common application is the separation of solid from highly concentrated suspensions, which is used in the treatment of sewage sludges for dewatering where less consistent sediment is produced. In the food industries, special centrifuges can process a continuous stream of particle-laden liquid.
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| ==Process and technologies== | | ==Process and technologies== |
| There is a correlation between the size and density of a particle and the rate that the particle separates from a heterogeneous mixture, when the only force applied is that of gravity. The larger the size and the larger the density of the particles, the faster they separate from the mixture. By applying a larger effective gravitational force to the mixture, like a centrifuge does, the separation of the particles is accelerated. This is ideal in industrial and lab settings because particles that would naturally separate over a long period of time can be separated in much less time.
| | A '''sieve analysis''' (or '''gradation test''') is a practice to assess the particle size distribution (also called ''gradation'') of a granular material by allowing the material to pass through a series of sieves of progressively smaller mesh size and weighing the amount of material that is stopped by each sieve as a fraction of the whole mass. |
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| The rate of centrifugation is specified by the angular velocity usually expressed as revolutions per minute (RPM), or acceleration expressed as ''g''. The conversion factor between RPM and ''g'' depends on the radius of the centrifuge rotor. The particles' settling velocity in centrifugation is a function of their size and shape, centrifugal acceleration, the volume fraction of solids present, the density difference between the particle and the liquid, and the viscosity.
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| ==Output== | | ==Output== |
| The remaining liquid that lies above the precipitate is called a supernatant or supernate.
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| ==Technology providers== | | ==Technology providers== |
| ===ABC=== | | ===ABC=== |