Question

What is the purpose of Electrorefining?

Answer 1

Electrorefining of metals:

• Electrorefining of metals can be defined as the extraction of metals from their ores by means of electrolysis.
• It takes place by taking the impure metal as anode and pure metal as cathode placed alternately in a bath containing $5\%{\mathrm{SnCl}}_2$ with $5-10\%\mathrm{HCl}$ solution.
• During electrolysis, the anode is oxidized which is then reduced at the cathode as pure. The impurities present in the anode are deposited below the anode in the form of anode mud.

Example:

• Copper is refined using an electrolytic method. Anodes are of impure copper and pure copper strips are taken as a cathode.
• The electrolyte is acidified solution of copper sulfate and the net result of electrolysis is the transfer of copper in pure form from the anode to the cathode.
• The reactions taking place at the anode and cathode are depicted below:

$$\begin{gathered} \mathrm{Anode}:\mathrm{Cu}\left(\mathrm{s}\right)\to {\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{–} \\ \mathrm{Cathode}:{\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{–}\to \mathrm{Cu}\left(\mathrm{s}\right) \end{gathered}$$

Purpose of Electrofining:

• It is mainly used for the purpose of purification of metals from their ores on a large scale.