Learn derivation of centrifugation. Centrifugation is used to separate two immiscible liquids or solid from liquid by the centrifugal force.
What is centrifugation?
It is a unit operation process, used to separate two immiscible liquids or solid from liquid by the centrifugal force. When simple separation technique like filtration is difficult to separate small particles then centrifugation can be very useful. For highly viscous mixture, particles size below 5 micrometers can be separated.
Theories of centrifugation
Particles size with above 5 micrometers undergoes with simple sedimentation process due to gravitational force. Sedimentation is dependent upon the different densities of dispersed phase and dispersion phase.
Above 5 micrometers sized particles can be separated by simple filtration. Size below 5 micrometers follow Brownian motion rules and separated by centrifugation.
If the densities of phases are not much different to each other densities, then separation will be difficult for normal techniques of separation. But, by applying centrifugal force separation can be very easy, because centrifugal force increases the sedimentation.
Procedure of centrifugation
A mixture of solid and liquids or two immiscible liquids should place in the centrifuge container. Rotate the container into high speed.
For the centrifugal force, particles will throw outside or separate from mixture. Finally, the centrifuge equipment preserves the floatable layer of pure liquid at the bottom of the centrifuge container.
Derivation of centrifugation
Mass of phases denoted as ‘m’, which will rotate a circular path denotated as ‘r’ (radius) at a velocity (v). So, the force acting on radius,
What are centrifuges?
Equipment’s which are used for centrifugation is known as centrifuges. Based on the mechanism of separation centrifuge classified into two types, sedimentation centrifuge and filtration centrifuge.
What is sedimentation centrifuge?
It is defined as a centrifuge process, by which solid particles undergoes sedimentation on basis of different densities of two or more phases of mixture. Sedimentation centrifuges are, continuous horizontal centrifuge, super centrifuge and conical disc centrifuge.
1) What is a continuous horizontal centrifuge?
Without a porous medium separation is continued. Separation is based upon the different densities of solid and liquid phases.
In this centrifuge solids will sediment due to centrifugal action. Latterly, solid materials are carried out and discharged by the conveyor, while liquid phase will be drain continuously.
2) What is supercentrifuge?
This is a continuous centrifuge used for separating two immiscible liquid phases. Separation based upon the different densities between two immiscible liquid phases.
Heavy liquid is thrown to super-centrifuge wall, while lighter liquid constantly stays in inner layer of centrifuge.
3) Wat is conical disc centrifuge?
It is also known as ‘de loral centrifuge’. In this centrifuge complete separation can be done. Low concentrated immiscible liquids or solids can separate by this centrifuge.
During centrifugation, solids are thrown outwards of the centrifuge. But the lighter liquid can be easily collected from the top of centrifuge.
What are the uses of sedimentation centrifuge?
- For separation of blood plasma from blood.
- For removing bacteria from bacterial enzyme.
- Lanolin can be extracted from wool by the sedimentation centrifuge.
- For purification of oils.
What is filtration centrifuge?
A centrifuge, by which solid and liquid phases are separated by the porous medium. Separation depends upon the different densities.
In this type of centrifuge container contains a porous wall. Which helps to pass liquid phase and retained solid phases. This centrifuge classified as, perforated basket centrifuge, semi-continuous centrifuge and non-perforated basket centrifuge.
What is perforated basket centrifuge?
Perforated basket centrifuge is also known perforated bowl centrifuge. It is a filtration centrifuge which separate solid and liquid phases through a perforated wall.
It consists of basket, motor, filter cloth. Perforated basket centrifuge used for separation of crystalline drugs from mother liquor.
What is semi continuous centrifuge?
It is filtration centrifuge use to separate liquid and solid phase through a perforated wall. During centrifugation, liquid phase passes through perforated wall, while solid phase retains in the bowl.
It consists of a vertical perorated basket, knife for cutting the solid cakes. feed and wash pipe. Semi-centrifuge is used for faster centrifugation.
What is non-perforated centrifuge?
This centrifuge separates solid and liquids according to their densities without porous medium. This follows sedimentation mechanism, that’s why it is known as sedimentation centrifuge.
It consists of a basket(steel), motor, skimming tube and filter cloth. Non-perforated basket centrifuge is used to separate high resistance solids from liquid flow.
What are the uses of filtration centrifuge?
- For removing unwanted solids from a liquid.
- Forn purification of insulin.