What is the Difference Between Sedimentation and Flotation?

Sedimentation and flotation are two different processes used in various industries, such as mining and wastewater treatment, to separate solids from liquids. The key difference between the two lies in the mechanisms they use to achieve separation:

Sedimentation:

• Involves the settlement of solid particles due to gravity, allowing them to sink to the bottom of the container.
• Typically used in water or wastewater treatment to reduce particle concentrations, either before or after coagulation and flocculation.
• The velocity of the water is lowered below the suspension velocity, causing the suspended particles to settle out of the liquid.
• Examples include the formation of sediment at the bottom of a lake or the settling of particles in a lamella separator.

Flotation:

• Uses the buoyancy of air bubbles to separate solids from liquids, allowing light particles to float to the top.
• Employs gas bubbles as a transport medium, with hydrophobic particulate matter attaching to the bubbles and rising to the surface.
• Can be used in mineral processing to separate valuable minerals from surrounding rock or in wastewater treatment to remove insoluble contaminants, fats, and oils.
• Examples include dry leaves floating on the surface of a river or the flotation of valuable minerals in mineral processing.

In summary, sedimentation relies on gravity to separate solids from liquids, while flotation uses the buoyancy of air bubbles to achieve the separation.

Comparative Table: Sedimentation vs Flotation

Here is a table comparing the differences between sedimentation and flotation:

In summary, sedimentation relies on gravity to separate solids from liquids, while flotation uses the buoyancy of air bubbles to achieve the same purpose. Sedimentation is the process of settling out of the fluid due to the force acting on particles, such as gravity, centrifugal acceleration, or electromagnetism. On the other hand, flotation involves attaching air bubbles to solid particles, making them more buoyant and causing them to rise to the surface.