How is copper extracted from its sulphide ore?

Copper is extracted from its sulphide ore through a process involving roasting, smelting, and electrolysis.

The first step in the extraction of copper from its sulphide ore is roasting. This is done by heating the ore in the presence of excess air. The copper sulphide ore, known as copper pyrites (CuFeS2), is heated in a blast furnace. The purpose of roasting is to convert the ore into its oxide form. This is achieved by the reaction of the sulphide ore with oxygen to produce copper(I) oxide (Cu2O) and sulphur dioxide (SO2).

The next step is smelting. The roasted ore is mixed with coke and sand and then heated in a furnace. The purpose of smelting is to reduce the copper(I) oxide to copper. This is achieved by the reaction of the copper(I) oxide with carbon (from the coke) to produce copper and carbon dioxide. The sand acts as a flux, which reacts with any impurities present to form a slag, which can be easily removed.

The final step is electrolysis. The impure copper obtained from the smelting process is purified using electrolysis. The impure copper is used as the anode, a strip of pure copper is used as the cathode, and an aqueous solution of copper(II) sulphate is used as the electrolyte. During electrolysis, copper ions from the anode dissolve into the electrolyte and are deposited on the cathode as pure copper. Any impurities in the copper fall to the bottom of the electrolysis cell as anode sludge.

In summary, the extraction of copper from its sulphide ore involves a three-step process of roasting, smelting, and electrolysis. Each step is crucial in obtaining pure copper from the sulphide ore.