Question

A process employed for the concentration of a sulphide ore is:
A. Froth floatation
B. Gravity separation
C. Froth separation
D. Gravity floatation

Answer 1

Hint: First eliminate options that show processes that do not exist. Then think about which process is used for concentration of ores and which is used for separation.

Complete answer:
The processes ‘Froth separation’ and ‘Gravity Floatation’ simply do not exist and we can thus eliminate those options.
Of the remaining two processes, the gravity separation process that is used for separation of either dry granular mixtures or suspensions. In these cases, gravity is clearly sufficient to carry out the separation of the 2 components that are involved. Thus, this process cannot be used for the concentration of the sulphide ores.
The froth floatation process is a process that is used industrially for the concentration of sulphide ores of various minerals. This process separates the hydrophilic (water-loving) components of the given mixture from the hydrophobic (water-fearing) components. The mixture is aerated and a chemical is added to make the required, finely-divided material adhere to the bubbles and rise to the top as froth. The gangue settles at the bottom and is removed. The process that makes the re settle and the gangue float to the top is known as the ‘Reverse Floatation Technique’. This process is used mostly for the concentration of sulphide ores.
So, the correct answer is “Option A”.

Note: Please do not get confused as to why the froth floatation process is a process used for concentration. Although, initially it seems like a separation process, the overall volume of the ore mixture is reduced while retaining the required material. This implies that the ore undergoes concentration in this process.