Introduction:
The froth flotation process is a widely used method for the benefaction of ores. It is based on the principle of difference in the wetting properties of the ore and gangue particles with water and oil. In this process, the ore is finely ground and mixed with water and a suitable collector, such as pine oil or xanthates. Air is then passed through the mixture to produce a froth containing the ore particles, which can be collected and separated from the gangue.

Explanation:
The reason why the ore particles float in the froth flotation process is because their surface is not easily wetted by water. This is due to the hydrophobic nature of the ore particles, which means they have a tendency to repel or resist wetting by water. On the other hand, the gangue particles, which are usually made up of minerals that are hydrophilic or easily wetted by water, sink to the bottom.

Hydrophobic nature of ore particles:
The hydrophobic nature of the ore particles is attributed to their surface properties. These particles usually have a thin film of adsorbed collector molecules on their surface, which makes them hydrophobic. The collector molecules are attracted to the surface of the ore particles and form a monolayer, which reduces the surface energy and makes the particles repel water.

Formation of froth:
When air is passed through the mixture of ground ore and water, it creates bubbles that carry the ore particles to the surface. The collector molecules on the surface of the ore particles act as a bridge between the particles and the air bubbles. They attach to the air bubbles, causing them to become hydrophobic and carry the ore particles to the surface, forming a froth.

Separation of ore and gangue:
The froth containing the ore particles is collected and separated from the gangue particles. This can be done by skimming off the froth or by using mechanical devices to scrape off the froth. The separated froth is then further processed to obtain the desired ore concentrate.

Conclusion:
In conclusion, the reason why the ore particles float in the froth flotation process is because their surface is not easily wetted by water. This is due to the hydrophobic nature of the ore particles, which is attributed to the presence of collector molecules on their surface. The formation of froth and the subsequent separation of ore and gangue particles allow for the benefaction of ores in this process.