Question

What is the difference between electrowinning and electrorefining?

Answer 1

Hint: Electrowinning is also known as electroextraction. Both electrowinning and electrorefining are almost similar processes that help to remove impurities from the metal. Both of these processes use the electroplating method on a very large scale.

Complete Step by Step Solution:
Electrowinning is also commonly known as electroextraction. It is a process of electrodeposition of metals from their ores which have been put in an aqueous solution. The process of putting ore in the solution is commonly known as leaching. Electrorefining is also similar to electrowinning, as both of these methods are used to remove the impurities from the metal. Both of these methods use electroplating and are used for the purification of non-ferrous metals.

In electrowinning, the current is passed from an anode that is inert in nature, that is placed in a leaching solution that contains dissolved metal ions. The metal is recovered by the process of electroplating and is deposited on the cathode.

In the process of electrorefining, the anode comprises the metal that is impure and needs to be purified. The impure metal that is needed to be purified undergoes oxidation and dissolves into the solution. The ions of the metals migrate through the acidic solution of electrolyte and deposit on the cathode through the process of electroplating. The impurities get settled into the solution. The metals purified through these processes are known as electrowon.

Note: These processes also have a wide variety of applications such as:
1) It helps in the purification of non-ferrous metals.
2) These are the only processes that are employed for the purification and production of aluminium.
3) Many electrorefining systems are available that help to remove the toxic metals from the industrial wastes.