Question

Froth flotation method is used for the concentration of-

Answer 1

Hint: Froth flotation method is a method in which important minerals are separated by its impurities. It is a separation process in which froth is created on which minerals are separated out. It is selectively used for separating hydrophobic material from hydrophilic material.

Complete Step by step answer: Froth flotation is a technique that is used selectively for materials that are hydrophobic or hydrophilic. Hydrophobic means water repelling and hydrophilic means water loving that has affinity for water.
Froth flotation process starts with increasing the surface area of ore. Firstly, the ores are crushed into fine powder and mixed with water. This mixture is called a slurry. Now surfactant chemical is added to it to enhance the hydrophobic nature of minerals. The slurry has converted to pulp now. This pulp is added to the water filled container. And then air jets are forced into it to create bubbles. The minerals are repelled by water and get attached to bubbles. As these bubbles rise up the mineral also comes with them, as the mineral is sticking to those bubbles. Then this froth is separated and further processing of minerals carry out with them like refining and extraction.
The principle behind this process is that there is a difference between wetting ability of the ore and impurities. If the minerals are hydrophobic then only it gets stuck to the froth. On the other hand impurities should be then water loving so that impurities remain dissolved with water.

This method is used for metals of low reactivity like sulphur.

Note: Sulphide ores are hydrophobic in nature and easily wetted by oil which then will float on water. Now this is converted into fine powder and then added to water. After this pine oil is added to this slurry to form pulp. The air bubbles are then created by air jets and sulphide ores comes up with the froth.