Question

Cassiterite is concentrated by:
(A) Levigation
(B) Electromagnetic separation
(C) Floatation
(D) Liquefaction

Answer 1

Hint: To answer this question, you must recall the various processes of concentration of ores given in the question. Cassiterite is an ore of tin and is commonly known as tinstone. Tin is not magnetic in nature and thus the ore can be concentrated by removal of the magnetic impurities like iron and manganese.

Complete step by step solution
Electromagnetic separation: It is the process by which the magnetic substances are separated from the non- magnetic ones by subjecting them to magnetic force. It is used to separate non- magnetic unwanted impurities from metallic ore. It can also be used to separate the magnetic impurities from non- magnetic ore. Thus, this process can be used for the concentration of the ore Cassiterite.
The correct answer is B.

Note:
Levigation: It is the process of concentration of ore by removing the heavy ore particles from lighter gangue particles or impurities by washing the ore with water. The light impurity particles are washed away by the stream of water while the heavy ore particles settle down.
Floatation: It is the process used for the purification of sulphide ores. It is based on the principle of the difference in wetting properties of ore particles and the gangue particles. The ore particles are selectively wetted with pine oil and is separated as froth
Liquefaction: This process involves the conversion of a gas into a liquid. A gas when subjected to higher pressure and low temperature liquefies. It is not a process of concentration of ores.