Question

Copper's is extracted from copper pyrites ore by heating in a blast furnace. The method is based on the principle that

(a) Copper has more affinity for oxygen than sulphur at high temperature

(b) Iron has less affinity for oxygen than sulphur at high temperature 

(c) Sulphur has less affinity for oxygen at high temperature 

(d) Copper has less affinity for oxygen than sulphur at high temperature

Answer 1

Correct option is (d) Copper has less affinity for oxygen than sulphur at high temperature

To extract copper from copper pyrites (CuFeS₂), the process involves several steps and is based on the principle that copper has a lower affinity for oxygen compared to sulfur at high temperatures. Here’s a step-by-step breakdown of the extraction process:

1. Understanding Copper Pyrites:

Copper pyrites, also known as chalcopyrite, has the formula CuFeS₂. It contains copper, iron, and sulfur.

2. Concentration of Ore:

The first step in the extraction involves the concentration of the ore through a process called froth flotation. This separates the copper-containing minerals from the gangue.

3. Roasting:

The concentrated ore is then roasted in the presence of oxygen. This process converts the sulfide minerals into oxides and releases sulfur dioxide (SO₂) gas.

The reaction can be represented as:

\(2Cu Fe S_2 + 5 O _2 \longrightarrow 2Cu_2 S + 2FeO + 4 SO _2\)

4. Bessemer Converter:

The next step involves the use of a Bessemer converter. The roasted product (Cu₂S) is introduced into the converter.

Here, air is blown through the molten mass, oxidizing the iron and sulfur.

5. Formation of Copper:

The reaction in the Bessemer converter can be summarized as follows:

\(2Cu_2 S + 3 O_2 \longrightarrow 2 Cu _2 O + 2 SO _2\)

Further oxidation leads to the formation of pure copper:

\(2 Cu_2 O + C \longrightarrow 4 Cu + Co\)

6. Principle of Extraction:

The method is based on the principle that copper has a lower affinity for oxygen than for sulfur at high temperatures. This allows for the selective reduction of copper from its sulfide form to the metal.

Thus, the extraction of copper from copper pyrites in a Bessemer converter is based on the principle that copper has less affinity for oxygen than sulfur at high temperatures, allowing for the effective separation and reduction of copper.