What is the Difference Between Froth Flotation and Gravity Separation

The key difference between froth flotation and gravity separation is that froth flotation method does not depend on the nature of the ore, whereas gravity separation depends on the physical and chemical properties of the ore.

Froth flotation and gravity separation are two important separation techniques useful in different industries. These two methods are different from each other in a few aspects.

1. Overview and Key Difference
2. What is Froth Flotation
3. What is Gravity Separation
4. Froth Flotation and Gravity Separation in Tabular Form
5. Summary – Froth Flotation vs Gravity Separation

What is Froth Flotation?

Froth flotation can be described as a process for selectively separating hydrophobic materials from hydrophilic materials. This process is important in mineral processing, paper recycling, and the waste water treatment industry. In ancient times, this process was used originally for the mining industry.

This method includes the grinding of the ore to be treated into particles. This step is known as comminution. Ideally, minerals are physically separated through a full liberation process. In this process, the particle size of the minerals generally ranges from 2 – 5000 microns (diameter). In the froth flotation method, we need to treat the aqueous slurry of the ground ore with the frothing agent.

For example, sodium ethyl xanthate is used as a collector in the flotation of galena to separate the material from sphalerite. Here, the xanthate anion combines with the ore particles, and the nonpolar hydrocarbon portion forms a hydrophobic layer. Air bubbles bring the particles to the water surface.

What is Gravity Separation?

Gravity separation is an analytical technique where we can separate two components either in a suspension or in a granular mixture using the force of gravity. However, this technique is useful only when it is sufficiently practical, for example, when the component mixture contains components with different specific gravity values. Typically, all gravity separation methods are common and similar because they use gravitational force as the dominant force.

Gravity separation is useful in many industries because it can be used to separate components from mixtures that are both wet (such as suspensions) and dry (such as granular forms). However, we can use other methods to speed up the separation process and make it more efficient. Examples of such other methods are flocculation, coagulation, and suction. Furthermore, gravity separation is useful in industries because it needs a low capital and operating cost. In addition, it may or may not use chemicals which has any environmental considerations.

For example, in agriculture, we can use gravity separation to remove impurities, admixture, insect damage, and immature kernels from crop products such as wheat, barley, peas, cocoa beans, linseed, etc. Moreover, we can use this method to separate and standardize coffee beans, cocoa beans, peanuts, corn, peas, rice, wheat, etc.

What is the Difference Between Froth Flotation and Gravity Separation?

Although both froth flotation and gravity separation techniques are useful in separating materials, they have some differences between them. The key difference between froth flotation and gravity separation is that the froth flotation method does not depend on the nature of the ore, whereas gravity separation depends on the physical and chemical properties of the ore.

The below infographic presents the differences between froth flotation and gravity separation in tabular form for side-by-side comparison.

Summary – Froth Flotation vs Gravity Separation

Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic materials, while gravity separation is an analytical technique that separates two components either in a suspension or in a granular mixture using the force of gravity. The key difference between froth flotation and gravity separation is that froth flotation method does not depend on the nature of the ore, whereas gravity separation depends on the physical and chemical properties of the ore.

Reference:

1. “Gravity Separation Method Is Based Upon.” Byjus – Learn Math, Coding, Music & Arts Online.

Image Courtesy:

1. “Flotation cell” By Dhatfield – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Gravity Filtration” By Suman6395 – Own work (CC BY-SA 4.0) via Commons Wikimedia