Question

If the impurity in a metal has a greater affinity for oxygen and is more easily oxidised than the metal, then the purification of metal may be carried out by [MP PMT 1997]
A) Poling B) Zone refining C) Electrolytic refining D) Cupellation

Answer 1

Metals obtained by reduction processes still contain some objectionable impurities and hence have to be refined. Refining techniques vary widely from metal to metal and also depend on the use to which a metal has to be put. Sometimes during refining some substances may have to be added to impart some desirable characteristics to the metal. In some cases a metal is refined to recover valuable by-products present as impurities. Some of the refining processes used are defined below.

By Poling

Answer 2

Hey there,

● Answer -
Cupellation

● Cupellation -
- Cupellation is a refining process in metallurgy, where ores are treated under very high temperatures to separate pure ore from impurities.
- The method is suitable if impurities have more affinity to oxygen than desired metal.
- This method is applied for refining of lead, cooper, zinc, arsenic, antimony, bismuth.
- For example extracting silver from lead.


Hope this helps you...