Impure copper is purified through a process called electrolysis, utilizing electricity passed through a solution containing copper compounds.
The Electrolytic Purification Process
The method involves setting up an electrochemical cell with specific electrodes and an electrolyte. Based on the process of electrolysis:
- Electrolyte: Electricity is passed through solutions that contain copper compounds, such as copper(II) sulphate. This solution allows ions to move, enabling the flow of electric current.
- Electrodes: Two electrodes are used:
- The anode (positive electrode) is made from the impure copper that needs to be purified.
- The cathode (negative electrode) is a strip of pure copper.
During the electrolysis process, under the influence of the electric current, copper from the impure anode dissolves into the solution as copper ions. These copper ions then migrate through the electrolyte and are deposited as pure copper onto the pure copper cathode. Impurities in the impure copper anode either dissolve in the solution or settle down below the anode as "anode mud".
Here's a simple breakdown of the setup:
| Electrode Type | Material | Charge | Role |
|---|---|---|---|
| Anode | Impure Copper | Positive | Where copper dissolves |
| Cathode | Pure Copper | Negative | Where pure copper is deposited |
This electrolytic method is highly effective for producing copper of very high purity.
