Which of the following is not a method for purification of metals:

The correct option is A

Calcination

The explanation for the correct option:

Purification of metal is a method of removing impurities in order to obtain metals of high purity.

(A) Calcination: Heating an ore in a limited supply of air or in the absence of air at a room temperature just below its melting point is known as “calcination.” Calcination is done for hydroxide and carbonate ores. It is used for extraction not for purification of metals.

The explanation for the incorrect option:

(B) Distillation: In this process, the impure metal is heated above its boiling point so that it can form vapors. The impurities do not vaporize, and hence they are separated.

(C) Liquation: It is a method of refining metals and is used when the impurities are not miscible with the metal and the melting temperature of the metal is lower than that of the impurities.

(D) Electrolytic refining: It is a technique for extracting and purifying impure or unrefined metals using the electrolysis process.
Thus, option (A) i.e., Calcination is the correct option as it is an extraction method.