In chemical process, separation play a important part in order to get something pure from a jumble of components. One of the process for separation is decanting. Decanting is a process that separate a mixture by using gravitational force. The mixture can be solid-liquid mixture (e.g. mud) or even two immiscible liquid (e.g. water and oil). A static decanting process is similar with sedimentation process which is mostly used in waste water treatment . A example of static decanter process can be refer to figure below.
Based on figure, due to the gravitational force, the liquid and solid of a mixture is naturally being separated due to its difference in mass. However, for the component to be totally separated naturally, it would take a long time.Thus, a 'dynamic' decanter is introduced to minimize the separation time and at the same time maximizing the output capacity and efficiency. The 'dynamic' decanter use a centrifugal force to expedite the process.
In a simple definition, centrifugal force is a force that draw a body away from the center of rotation.The 'pull' force is the result of the body attempt to move in a straight line due inertia. However, due to the restricted space, the body is seem to be 'attached' to the wall of the rotating system. In retrospect, the centrifugal force is similar like an artificial gravity but instead pulling the body towards it center, it push the body away from the axis of rotation. The artificial gravity that occurred on the body is simply a reaction force of the body towards the centrifugal force in the rotating system in accordance to the Newton Third Law. If you remember riding a Ferris wheel, you will notice that your body will feel the 'extra' gravitational force induce by the wheel rotation. A feeling that like you would be 'thrown' away during the wheel rotation. However, in order to crate a real centrifugal force, the rotation is need to be equivalent to the size of the system.
In practice, centrifugal force is used to separate the heavy component from the light component as the heavy ones would be push to the wall of the rotating container and be swept away by a inner conveyor. By manipulating the speed of the container rotation, we can achieve a better separation effect depending on the mixture. A video of a working horizontal centrifuge which is used in the industrial is shown below.
In the nutshell: A decanting process can be improved by using centrifugal force, a continuous circular motion that can induce a artificial gravitational force. A Ferris wheel ride, which is one of the application of centrifugal force, is technically safe as it rotate at a low speed.
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