How is copper purified using electrolysis?

Copper is purified using electrolysis by passing a current through a solution of copper salts, causing copper ions to deposit onto a cathode.

In the process of electrolysis for copper purification, an impure copper rod is used as the anode (the electrode where oxidation occurs) and a pure copper rod is used as the cathode (the electrode where reduction occurs). The electrolyte solution is a copper sulphate solution, which contains copper ions.

When the electric current is passed through the solution, copper ions from the impure copper anode are oxidised and dissolve into the solution. These copper ions are then attracted to the cathode, where they gain electrons and are reduced to form pure copper atoms. These pure copper atoms then deposit onto the cathode, gradually building up a layer of pure copper.

Impurities in the anode, including precious metals like gold and silver, do not dissolve into the solution. Instead, they fall to the bottom of the electrolysis cell as a sludge. This sludge can be collected and processed to extract these valuable metals.

The process continues until all the impure copper in the anode has been transferred to the cathode. The result is a pure copper cathode and a solution depleted of copper ions. This method is highly effective for purifying copper to a very high degree of purity.

In summary, electrolysis is a powerful method for purifying copper. It uses the principles of oxidation and reduction to selectively transfer copper ions from an impure anode to a pure cathode, leaving behind impurities and resulting in highly pure copper.