what is sedimentation? sedimentation is a method of separating entities based on their particle size...

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Sedimentation

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Page 1: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

Sedimentation

Page 2: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

What is Sedimentation?

Page 3: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

Sedimentation is a method of separating entities based on their particle size

It’s the process where a solid material gets deposited from a state of suspension or solution, in a fluid.

Page 4: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

Methods

Page 5: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

Sedimentation method is used for particle sizes ranging from 1 micrometer to 200 micrometers.

There are 3 commonly used methods:1) Andreasen pipette 2) Balance3) HydrometerAll these methods depend on the idea that

the terminal velocity of a particle in fluid is directly proportional to its size.

Page 6: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited
Page 7: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

The Andreasen apparatus consists of a 200 mm graduated cylinder which can hold up to 500ml of suspension fluid.

A pipette is located at the center of the cylinder and its held in position by a ground glass stopper so that its tip coincides with the zero level.

A three way tap allows fluid to be drawn into a 10ml reservoir which can then be emptied into a beaker of centrifuge tube.

Page 8: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

Procedure

Page 9: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

1. Allow a homogenous suspension to settle in a cylinder, take samples from the settling suspension at a fixed horizontal level over intervals of time.

2. Each sample will contain a representative sample of the suspension, all of which have settled below the level of the sampling point.

3. The concentration of solid in a sample is taken at a time t.

4. This concentration is expressed as a percentage of the initial concentration, gives us the percentage of particles whose falling velocity are equal to or less than x/t. Substitution in the equation below gives us the corresponding stokes' diameter.

Page 10: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited
Page 11: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

Advantages & Disadvantages

Page 12: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

The equipment required are simple to use and inexpensive.

You can measure a wide range of sizes with accuracy and the results can be reproduced, increasing it’s reliabilty.

Page 13: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

Sedimentation analyses must be carried out at concentrations which are low enough for interactive effects between particles to be negligible. This is so that the terminal velocities can be assumed to be equal to those of the isolated particles.

Careful temperature control is necessary to suppress convection currents

Large particles create turbulence, causing them to slow down and get recorded as undersized.

Particles have to be completely insoluble in the suspending liquid.

Page 14: What is Sedimentation? Sedimentation is a method of separating entities based on their particle size It’s the process where a solid material gets deposited

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